FAQ

The power system is a complex and extensive engineering network that involves various stages from power generation to end-user consumption. Its primary function is to convert energy from natural sources into electricity and deliver it through a series of devices and networks to various end users. The structure of a power system can be divided into five main components: generation, transmission, transformation, distribution, and consumption. These components are interconnected and operate in a coordinated manner, forming an interdependent and cohesive system.

1. Generation

Generation is the starting point of the power system. Power plants convert various energy sources, such as coal, natural gas, oil, hydropower, nuclear energy, wind energy, and solar energy, into electricity. There are various types of power plants, with thermal power plants being the most common. These plants burn fossil fuels (like coal and natural gas) to heat water, producing steam that drives turbines, which in turn rotate generators to produce electricity. Hydropower plants utilize the potential energy of water, converting the kinetic energy of flowing water into mechanical energy through turbines, which is then converted into electricity. Nuclear power plants generate electricity through nuclear fission reactions that release immense energy. In recent years, renewable energy sources such as wind and solar power have become increasingly prominent. These renewable power plants directly generate electricity from wind and solar radiation, offering environmentally friendly and sustainable energy solutions.

2. Transmission

Transmission refers to the process of transporting electricity generated at power plants through high-voltage transmission lines to load centers or substations located far from the generation site. To minimize energy losses during transmission, electricity is typically transmitted at high or ultra-high voltages. The transmission network consists of a series of transmission lines, switching equipment, and other related facilities. These components not only ensure the efficient delivery of electricity but also rapidly isolate problems in case of system failures to prevent broader outages. As transmission distances increase, high-voltage transmission becomes particularly important because higher voltages result in lower currents and, consequently, reduced transmission losses.

3. Transformation

Transformation is an essential part of the power system, primarily functioning through substations to step up or step down the voltage of electricity. Electricity generated by power plants typically has a lower voltage, which needs to be stepped up before leaving the power plant for long-distance transmission. Before the electricity reaches load centers or end users, the voltage usually needs to be stepped down again to meet the requirements of the distribution network and the end users. Substations are the core equipment in this process. They use transformers to convert the voltage from one level to another and rely on a series of switches, circuit breakers, and control devices to ensure the safe transmission and distribution of electricity.

4. Distribution

The distribution network is the bridge between substations and end users in the power system. The primary task of the distribution network is to further distribute the electricity, stepped down by substations, to various consumers. The distribution network typically consists of a medium-voltage distribution network and a low-voltage distribution network. The medium-voltage distribution network is responsible for transmitting electricity to various distribution transformers, while the low-voltage distribution network distributes electricity from the distribution transformers to residential, commercial, and industrial users. The design and operation of the distribution network require a high degree of reliability and flexibility to adapt to the load demands of different users and quickly restore power in the event of a fault.

5. Consumption

Consumption is the final stage of the power system and represents the end-use of electricity. Various users convert electricity into other forms of energy, such as mechanical energy, thermal energy, and light energy, through electrical devices. Industrial users typically require large amounts of electricity to power heavy machinery, production lines, and other industrial facilities. Commercial users use electricity for lighting, heating, air conditioning, and other office and commercial activities. Residential users mainly use electricity for lighting, household appliances, and heating. Changes in electricity demand directly affect the stability of the power system, so utility companies need to adjust the system in real time based on demand changes to ensure a balance between supply and demand.

As one of the fundamental infrastructures of modern society, the power system must ensure a stable and reliable supply of electricity. To achieve this goal, the design and operation of power systems must consider various factors, including the efficiency of electricity production, transmission, and distribution, the safety and stability of the system, environmental protection, and economic efficiency. Through scientific planning and technological advancements, power systems are continuously optimized and upgraded, providing robust energy support for the development of human society.

Voltage level is a key parameter in the power system, which indicates the voltage value used in the transmission and distribution of electric energy at different stages. According to the functional requirements and safety requirements of the power system, the voltage level is divided into several different grades to meet the different requirements of each link of power generation, transmission, distribution and consumption. This division not only helps optimize the efficiency of power transmission, but also ensures the reliability and safety of the system.

1. Basic classification of voltage levels

In the power system, voltage levels are usually classified according to the voltage value, mainly including the following categories:

1. Low voltage (LV):

Low voltage generally refers to the voltage level below 1kV. Low voltage systems are widely used in residential areas, commercial areas and some small industrial facilities for power supply. Common low voltage values include 220V and 380V. The former is usually used for power supply of household and small commercial appliances, while the latter is often used for small industrial equipment and some high-power household appliances. Low voltage voltage level has relatively high safety due to its low voltage, but due to the limited transmission distance, it is suitable for short-distance power supply.

2. Medium Voltage (MV):

Medium voltage levels are generally between 1kV and 35kV, and are mainly used in distribution networks. Medium voltage power systems are common in urban distribution networks and internal power supply of medium and large industrial facilities. Typical medium voltage levels are 10kV, 20kV and 35kV. These voltage levels are usually stepped down by distribution transformers before being provided to end users. Medium voltage systems can effectively transmit power over long distances while maintaining a certain transmission efficiency and safety.

3. High Voltage (HV):

High voltage levels usually refer to voltages between 35kV and 220kV, which are mainly used for long-distance transmission and power transmission between substations. Common high voltage levels are 110kV and 220kV, which are widely used in inter-regional transmission networks. In high voltage transmission systems, due to the high voltage and relatively low current, this can effectively reduce the loss of power during transmission, while reducing the cross-sectional area of the transmission line, thereby reducing costs.

4. Extra High Voltage (EHV):

Extra high voltage refers to voltage levels between 220kV and 1000kV, mainly used for UHV transmission lines. The UHV power system is designed to transmit large amounts of electrical energy over longer distances, and is usually used to transmit electricity from distant power plants to load centers. Typical UHV levels include 330kV, 500kV, and 750kV. Within this voltage range, the power transmission efficiency is very high, but the requirements for power equipment are also more stringent, including higher insulation requirements and more complex system protection mechanisms.

5. Ultra High Voltage (UHV):

Ultra high voltage refers to voltage levels of 1000kV and above. The UHV power system is an important direction for the development of modern power system technology, mainly used for large-scale power transmission over ultra-long distances. The application of UHV can greatly reduce energy loss in long-distance transmission and improve the economy and stability of the system. China is one of the few countries in the world that has mastered UHV technology and applied it on a large scale. Typical UHV levels include 1000kV AC transmission and ±800kV DC transmission.

2. The significance of voltage level division

The division of voltage levels is of great significance in the power system:

1. Optimizing power transmission: Different voltage levels are suitable for different transmission distances and load requirements. Through reasonable voltage level selection, the power system can minimize power loss and improve economic benefits while meeting power supply needs.

2. Safety and reliability: The division of voltage levels can also improve the safety and reliability of the power system. By operating at different voltage levels, the power system can effectively isolate problems when faults occur and reduce the impact on the entire system.

3. Economy: Different voltage levels correspond to different equipment and material requirements. High-voltage equipment is usually more expensive, but its efficient transmission capacity can make up for this. Low-voltage equipment is less expensive and suitable for short-distance power supply. Therefore, the reasonable division of voltage levels helps to control the construction and operation costs of the power system.

The division of voltage levels is a basic and important principle in the design and operation of power systems. Through reasonable voltage level division, the power system can ensure the safety and reliability of the system while ensuring efficient transmission of electric energy, providing strong support for the society's power supply.

A high-voltage load switch is a switch device used to connect and disconnect high-voltage power lines. Its main function is to perform disconnection and connection operations when the circuit is loaded, while providing certain protection. It can carry and disconnect normal operating currents, but cannot be used to cut off short-circuit currents. Therefore, it is usually used in conjunction with fuses or other protective devices to protect the power system.

Function

The main functions of high-voltage load switches include:

1. Disconnecting and connecting load currents: It can connect and disconnect circuits in power systems under normal operating conditions. It is suitable for operations with loads, so it can be used for load control and segmentation of power lines.

2. Provide certain fault protection: Although high-voltage load switches cannot cut off short-circuit currents, they can provide basic fault protection in overload conditions by linking fuses or other protective devices.

3. Maintenance and overhaul: Isolating lines or equipment through disconnecting switches facilitates daily maintenance and overhaul of power equipment.

4. Controlling power systems: In power distribution, it can be used to control the operating status of power lines and realize the dispatching and load management of power grids.

Classification

According to different classification standards, high-voltage load switches can be divided into the following categories:

1. Classification by arc extinguishing medium

- Air-insulated load switch: uses air as the arc extinguishing medium, suitable for high-voltage systems with lower voltage.

- SF6 gas load switch: uses sulfur hexafluoride (SF6) gas as the arc extinguishing and insulating medium. This type of load switch has strong arc extinguishing ability and is used in high-voltage systems. It has good insulation performance and arc extinguishing characteristics.

- Vacuum load switch: uses vacuum as the arc extinguishing medium. The arc is extinguished quickly when it is opened. It has a high arc extinguishing speed and is widely used in medium-voltage power systems such as 10kV and 35kV.

2. Classification by operation method

- Manual load switch: The switch is disconnected and connected through manual operation. It is suitable for occasions where operation is not frequent. It is simple to operate and has low cost.

- Electric load switch: The switch is remotely controlled by the electric operating mechanism. It is suitable for occasions that require remote or automatic control and is easy to operate.

- Spring-operated load switch: Relying on the mechanical energy of the energy storage spring to disconnect or connect the circuit, often used in conjunction with automatic control devices.

3. Classification by use environment

- Indoor load switch: Installed in indoor electrical cabinets or switch cabinets, with better environmental protection, often used in factories, distribution rooms and other places.

- Outdoor load switch: Installed in outdoor power lines or substations, designed to withstand various severe weather conditions, such as wind, rain, snow, humidity, etc., suitable for outdoor power facilities.

4. Classification by whether it is equipped with a fuse

- Load switch with fuse: Used in combination with a high-voltage fuse, the fuse is responsible for short-circuit protection, and the load switch is responsible for disconnecting the load current. This combination device provides more comprehensive protection and is often used in transformer protection.

- Load switch without fuse: It only has the function of a load switch and cannot perform short-circuit protection independently. It is usually used in combination with other protection devices.

Main features

1. Suitable for load operation: High-voltage load switches are designed to disconnect and connect normal load currents in circuits, so they can be operated under load without causing damage to the electrical system.

2. Unable to cut off short-circuit current: High-voltage load switches have limited breaking capacity and cannot cut off short-circuit currents that greatly exceed the rated current. Therefore, they are usually used in conjunction with short-circuit protection devices such as high-voltage fuses to provide all-round protection.

3. High reliability and long life: High-voltage load switches are usually made of durable materials and designed for long service life, suitable for frequent operation or working in harsh environments.

4. Low maintenance requirements: In particular, load switches using vacuum or SF6 gas arc extinguishing media have low maintenance frequency and good working stability.

Application scenarios

High-voltage load switches are widely used in power systems such as substations, distribution networks, industrial and mining enterprises, and power transmission lines, especially in power lines with high voltage levels and frequent operations. They are often used for:

1. Transformer protection: High-voltage load switches are used in combination with fuses to provide load protection and short-circuit protection for transformers.

2. Power distribution lines: used to control the segmentation and connection of distribution lines, facilitating line maintenance and operation scheduling.

3. Power grid automation system: In the power automation system, high-voltage load switches are often used as part of the automatic control equipment to achieve flexible control of power grid operation through remote operation.

In summary, high-voltage load switches are commonly used load control equipment in power systems. They can realize load separation and combination operations, have high safety and reliability, and are particularly suitable for use in medium-voltage and high-voltage distribution systems.

A high-voltage fuse is an overcurrent protection device used to protect high-voltage power equipment. Its main function is to quickly cut off the fault current by melting the fuse when an overload or short circuit occurs in the circuit, thereby protecting the power equipment from damage. High-voltage fuses are widely used in transformers, transmission lines and distribution systems.

Basic structure

The basic structure of a high-voltage fuse is relatively simple and mainly consists of the following parts:

1. Fuse: This is the core component of the fuse, usually made of silver, copper or other metal wires with good conductivity. When the current exceeds the design value, the fuse quickly melts, thereby cutting off the circuit. The design of the fuse is adjusted according to the current level.

2. Fuse tube: The fuse is installed in the fuse tube, which is generally made of high-temperature resistant and highly insulating materials (such as ceramics, glass or epoxy resin). The function of the fuse tube is to protect the fuse and prevent the arc when the fuse melts from causing damage to the external environment.

3. Terminals and leads: The terminals are used to connect the fuse to the circuit. The lead wires are connected to both ends of the fuse, and the circuit is cut off by the action of the fuse.

4. Arc extinguishing device: High-voltage fuses are usually equipped with arc extinguishing devices, which are mainly used to control the generation of arcs when the fuse melts. The arc extinguishing device can quickly extinguish the arc to prevent further damage to the circuit.

Function

The main functions of high-voltage fuses include:

1. Overload protection: When the current in the circuit exceeds the rated value of the fuse (for example, when the transformer load exceeds the rated capacity), the fuse will melt and cut off the circuit to prevent electrical equipment from being damaged due to overload.

2. Short-circuit protection: In the case of a short circuit, the current increases sharply, and the fuse of the high-voltage fuse melts quickly, cutting off the circuit, thereby protecting the equipment from serious damage caused by the short circuit.

3. Interrupting fault current: The fuse not only provides protection in normal operation, but also interrupts the fault current when a fault occurs in the power grid to prevent the accident from further expanding.

Classification

According to different standards, high-voltage fuses can be divided into the following categories:

1. Classification by purpose

- Protective fuses: Mainly used to protect transformers, motors, mutual inductors and other equipment, and can cut off the circuit in overload and short circuit conditions.

- Current-limiting fuses: When a short circuit occurs, the current-limiting fuse can limit the short-circuit current passing through the fault point to prevent a wider range of damage to the power system.

2. Classification by installation location

- Indoor fuses: Designed for indoor installation, commonly used for the protection of indoor switchgear and power equipment.

- Outdoor fuses: Designed for outdoor substations and lines, and can withstand environmental factors such as wind, rain, and temperature changes.

3. Classification by structural form

- Enclosed fuses: The fuse is encapsulated in a closed container and usually has good arc extinguishing and insulation properties.

- Open fuses: The fuse is exposed to the outside air and is usually used under low voltage conditions, with poor arc extinguishing performance.

4. Classification by current limiting type

- Non-current limiting fuse: Mainly used under low fault current conditions, the rise of short-circuit current cannot be limited after the fuse is blown.

- Current limiting fuse: It can limit the rise of current when short-circuit current occurs, reducing the impact on the equipment.

Application scenarios of high-voltage fuses

High-voltage fuses are mainly used to protect key equipment and lines in power systems. Common applications include:

1. Transformer protection: High-voltage fuses can be used for overload and short-circuit protection of small and medium-sized transformers.

2. Motor protection: In industrial equipment, fuses are used for overload and short-circuit protection of motors to prevent motors from burning.

3. Distribution line protection: High-voltage fuses are widely used in power distribution networks to protect transmission lines and power transformers from fault currents.

Advantages

- Simple structure: High-voltage fuses are compact, easy to install, and relatively simple to maintain.

- Quick response: They can respond quickly and cut off the current when a fault occurs, protecting the equipment from serious damage.

- Economical and practical: Compared with other protective devices (such as high-voltage circuit breakers), high-voltage fuses are low-cost and suitable for use in a wide range of power systems.

Notes

Although high-voltage fuses have good protection functions, they are usually not suitable for frequent operation. The action of the fuse is one-time, that is, once the fuse is blown, it needs to be replaced before it can be put back into use.

A transformer is a measuring and protection device used in power systems. Its main function is to convert high voltage or large current into standard small voltage or small current for use in power equipment or instruments. Transformers are usually used to monitor voltage and current, and cooperate with relay protection devices to protect equipment in power systems.

Transformers are divided into two categories: current transformers (CT) and voltage transformers (PT). They can convert high voltage and large current into lower, safe standard signals for easy use of measurement and control equipment.

Basic structure

The structure of the transformer varies depending on the type, but it usually consists of the following basic parts:

1. Core: The core of the transformer is usually made of high magnetic permeability silicon steel sheets, which can effectively guide magnetic flux and reduce energy loss. The core of the current transformer is mainly used to sense the current on the primary side to the secondary side, while the core of the voltage transformer is used to sense voltage changes.

2. Primary winding: The primary winding is directly connected to the power system. The primary winding of the current transformer is usually composed of thick and short wires, while the primary winding of the voltage transformer is wound with thinner wires and carries high voltage.

3. Secondary winding: The secondary winding is connected to the measuring instrument or relay protection device. The secondary winding of the current transformer generally has more turns to reduce the high current to the standard current; the secondary winding of the voltage transformer is used to convert the high voltage into a low voltage signal.

4. Insulation and casing: The winding and core of the transformer are usually installed in an insulating casing to ensure the insulation performance of the equipment and prevent leakage and other electrical accidents.

Working principle

1. Working principle of current transformer (CT)

The current transformer uses the principle of electromagnetic induction to convert the large current on the primary side into the small current on the secondary side.

- The coil on the primary side is connected in series in the main circuit and directly passes the primary current.

- The coil on the secondary side is connected to the measuring instrument or relay protection device, and the induced current generates a secondary current proportional to the primary current.

2. Working principle of voltage transformer (PT)

The voltage transformer is also based on the principle of electromagnetic induction, converting high voltage into low voltage.

- The primary winding is connected in parallel to the power line and bears the system voltage.

- The secondary winding is connected to the measuring device and provides the induced secondary voltage to the measuring instrument.

Working characteristics

1. Linear working range: The transformer shows good linearity within its rated working range, that is, the primary current/voltage and the secondary current/voltage are proportional. When the load changes, the transformer can ensure that the secondary output maintains an accurate proportional relationship with the primary side.

2. Good insulation performance: Since the primary winding is directly connected to high voltage or high current, the transformer usually has good insulation performance to ensure the safety of the system and personnel.

3. Secondary side safe voltage and current: The current transformer converts the primary high current into the secondary low current (usually 5A or 1A), and the voltage transformer converts the high voltage into the secondary standard low voltage (usually 100V or 110V). This enables the measurement and protection equipment to operate under safe working conditions.

4. High measurement accuracy: The transformer must have good accuracy, especially when measuring electric energy or protecting equipment. The error of the transformer will directly affect the measurement accuracy of the system and the reliability of equipment operation.

5. Protection function: Another important function of the transformer is protection. The current transformer can quickly feed back the fault current to the relay protection device, thereby quickly cutting off the faulty part and protecting the equipment from damage.

6. Magnetic saturation characteristics: The core design of the transformer will cause it to produce magnetic saturation when it exceeds a certain current or voltage, resulting in increased measurement errors. Therefore, the design of the transformer must ensure that saturation does not occur within the normal operating range.

Application scenarios of transformers

- Power system measurement: Transformers are used in substations, power lines and power stations to measure high voltage, high current and voltage.

- Power metering: In commercial and industrial situations, transformers are connected to electric energy meters for power metering.

- Relay protection system: In the power system, when a short circuit or overload occurs, the transformer transmits the current or voltage signal to the protection device to quickly cut off the faulty line.

A high-voltage combination switch (also called a high-voltage combination electrical appliance, such as a switch cabinet) is a device in a power system that integrates multiple functions and is used for the control, protection and measurement of high-voltage power lines. It is usually composed of components such as circuit breakers, disconnectors, grounding switches, current transformers, voltage transformers, and lightning arresters, which are compactly installed in a cabinet to improve the system's operating reliability, save space, and simplify installation.

Function

The main functions of high-voltage combination switches include:

1. Circuit breaker protection: The circuit breaker in the high-voltage combination switch can automatically cut off the fault circuit when the power system is overloaded or short-circuited, protecting electrical equipment from damage.

2. Control circuit: Through the circuit breaker or disconnector, the combination switch can realize manual or automatic control of the power line to meet the operation and dispatching needs of the power grid.

3. Measurement and metering: The current transformer and voltage transformer inside the combination switch can be used to monitor parameters such as current and voltage to help operation and maintenance personnel understand the line operation status.

4. Isolation function: The integrated isolating switch can isolate the equipment from the power system under no-load conditions, which is convenient for inspection and maintenance.

5. Grounding protection: The grounding switch can provide grounding operation to prevent personal injury caused by accidental energization of the power system during inspection.

Classification

The classification of high-voltage combination switches is usually based on structure, installation method, application and voltage level.

1. Classification by structure

- Metal-enclosed combined switch (GIS): All main equipment such as circuit breakers, isolating switches, transformers, etc. are installed in a metal-enclosed gas-insulated chamber, using sulfur hexafluoride (SF6) gas as the insulating medium. This design is suitable for occasions with limited space or poor environmental conditions, such as urban substations.

- Air-insulated combination switch (AIS): Using air as the insulating medium, the equipment is usually more dispersed and suitable for occasions with more space.

2. Classification by voltage level

- High-voltage combination switch: Usually suitable for voltage levels of 72.5kV and above. Widely used in the protection and control of high-voltage transmission lines.

- Medium voltage combination switch: usually used for voltage levels between 1kV and 72.5kV, used in medium voltage power distribution systems.

3. Classification by installation method

- Outdoor combination switch: designed for outdoor installation, can adapt to various weather conditions, widely used in substations and switch stations.

- Indoor combination switch: used for indoor installation, usually small in size, suitable for factories and distribution rooms.

4. Classification by functional module

- Fixed combination switch: all equipment is fixedly installed, suitable for occasions where load changes are not frequent.

- Drawer combination switch: each device is installed in a removable unit, which is easy to maintain and replace, and suitable for occasions with large load changes.

Advantages

- Space saving: The combination switch equipment has a compact structure and occupies a small area, especially GIS type equipment.

- Improve safety: Since key equipment (such as circuit breakers and disconnectors) are integrated in a closed system, external interference is reduced and the safety of operation is improved.

- Reduce maintenance costs: The closed design of the combination switch can effectively isolate external environmental factors (such as dust and moisture), reducing the maintenance workload.

Application scenarios

High-voltage combination switches are widely used in substations, distribution stations, industrial enterprises and other places, especially in urban centers, high-voltage transmission lines and new energy power generation systems such as wind power and solar power.

    Compensation equipment in power systems is mainly used to improve power quality, improve voltage stability and increase power factor, thereby optimizing system efficiency and reducing losses. The role, working principle and types of compensation equipment are as follows:

1. Role

    1. Improve power factor: In power systems, loads usually contain inductive components (such as motors, transformers, etc.), which causes the current to lag behind the voltage and reduce the power factor of the system. Low power factor means more reactive power, requiring more current to transmit the same active power, increasing line losses and equipment load. Compensation equipment reduces the system's reactive demand on the power grid by providing reactive power and improving the power factor.

    2. Voltage regulation: Compensation equipment can stabilize the voltage in the system and prevent voltage fluctuations, especially when high-power equipment is started and stopped, compensation equipment can play a role in voltage support.

    3. Reduce losses: By reducing reactive power transmission, compensation equipment reduces the current of the transmission line, thereby reducing power losses and improving the transmission efficiency of the system.

    4. Reduce the risk of equipment overload: Compensation equipment reduces reactive power transmission in the system, reduces the load of equipment such as generators and transformers, and extends the service life of the equipment.

2. Working Principle

    The working principle of the compensation equipment is mainly to adjust the voltage and power factor in the system by providing or absorbing reactive power. Reactive power is the electrical energy generated by inductive or capacitive loads. It cannot be directly used to do work, but the balance of reactive power in the power system is crucial to the stable operation of the power grid. The compensation equipment balances the impact of inductive or capacitive loads on the system by exchanging reactive power with the power grid.

3. Types

Compensation equipment can be divided into the following categories according to different functions and working principles:

1. Static VAR compensator (SVC):

- Working principle: SVC dynamically adjusts the reactive power in the system by adjusting the operating status of reactors and capacitors. The injection or absorption of reactive power is adjusted by thyristor rectifiers and filters to quickly respond to changes in system voltage.

- Function: SVC is mainly used to quickly respond to voltage fluctuations and is widely used in high-voltage transmission systems.

2. Shunt capacitor:

- Working principle: The shunt capacitor group offsets the reactive power generated by the inductive load by providing capacitive reactive power and improves the power factor.

- Function: Mainly used to improve the power factor in the distribution system, suitable for inductive loads that run for a long time.

3. Series capacitor:

- Working principle: The series capacitor is directly connected to the transmission line to compensate for the inductive reactance of the line and reduce the reactive power consumption of the line.

- Function: Improve the transmission capacity of the transmission line, reduce line losses, and is suitable for long-distance transmission systems.

4. Static synchronous compensator (STATCOM):

- Working principle: STATCOM is based on power electronics technology and controls the injection or absorption of reactive power by adjusting the output voltage of the inverter. Compared with SVC, STATCOM has a faster response speed and can maintain reactive power compensation function at low voltage.

- Function: Mainly used for dynamic voltage regulation and reactive power control, especially for distributed power sources such as wind farms and photovoltaic power stations.

5. Synchronous phase condenser:

- Working principle: Synchronous phase condenser is a rotating mechanical equipment that can provide reactive power according to demand, and controls the output of reactive power by adjusting the excitation current of the rotor.

- Function: It can continuously provide stable reactive power and is widely used in high-voltage transmission systems and power plants.

    The compensation equipment in the power system improves the power factor, stabilizes the voltage, and reduces power loss by providing or absorbing reactive power. Common compensation equipment includes shunt capacitors, series capacitors, SVC, STATCOM, and synchronous phase condensers.

RTV and PRTV are both anti pollution flashover coatings, which are now common anti pollution flashover coatings. PRTV, also known as RTV-2, is an upgrade of RTV and is the most commonly used coating in State Grid, power plants, and power generation groups. So, let's briefly introduce which performance of the upgraded anti pollution flashover coatings is better:

• High hydrophobicity

The hydrophobicity angle of PRTV coatings is generally greater than 90 degrees, while the hydrophobicity angle of PRTV coatings is greater than 100 degrees.

• Excellent corrosion resistance

PRTV coatings have excellent resistance to chemical and electrochemical corrosion, as well as resistance to acids, alkalis, salts, and most organic compounds. Capable of adapting to various harsh climatic environments and corrosive media environments.

• Unique surface performance

Has excellent electrical insulation performance.

• Unique non fouling performance

Anti dust adhesion, general dust can be automatically washed away by rainwater, and local stubborn stains can be adhered. Simply wipe with a cloth to restore the clean surface.

• Excellent physical and mechanical properties

The coating has excellent physical and mechanical properties: high adhesion, high hardness, high flexibility, high wear resistance, and impact resistance. Good adhesion and convenient construction. The perfect combination of flexibility and hardness on the surface can withstand wear, collision, and impact.

• Heat and cold resistance

It can withstand the test of severe cold and heat, and can be used normally within the temperature range of -40 ℃ -140 ℃, without peeling, wrinkling, peeling, or cracking.

1. Common anti pollution flashover measures

At present, there are five main methods for preventing pollution flashover of transmission line insulators.

(1) Regularly clean the insulators. Generally, it is cleaned once a year before the rainy season.

(2) Replace defective and zero value insulators. Regularly conduct insulation testing on insulator strings, and promptly replace defective and zero value insulators if found.

(3) Increase the unit leakage distance of the insulator string. The greater the leakage current on the surface of the insulator, the more severe the pollution flashover, and the magnitude of the leakage current is inversely proportional to the unit leakage distance of the insulator string. Therefore, it is possible to increase the number of insulator pieces or change them to pollution resistant insulators to increase the unit leakage distance of the insulator string.

(4) Using anti fouling paint. For insulators in heavily polluted areas, hydrophobic anti fouling coatings can be applied to their surface to enhance their anti fouling ability.

(5) Composite insulators shall be used. Composite insulators are composed of silicone rubber as the basic insulator. The use of composite insulators has been widely used in new transmission lines in recent years and is an effective measure to prevent pollution flashover.

2. Advantages and disadvantages of various anti pollution flashover methods

(1) Regular cleaning. This method is the most widely used and simplest method for preventing pollution flashover, and has been widely used by various power supply departments. The disadvantage is that cleaning is done periodically, which wastes a lot of valuable power outage time. Moreover, it is necessary to adopt low resistivity water sources, which are difficult to obtain in some areas.

(2) Regularly conduct insulation testing on insulator strings. In the case of a large number of insulators, the amount of labor is also significant. Especially in certain heavily polluted areas, the testing cycle should be shortened.

(3) Increase the number of insulator pieces appropriately. There are many methods to increase the current leakage value, but due to the influence of strength and wire height, the number of insulator pieces cannot be infinitely increased.

(4) Use hydrophobic coatings. The superiority is obvious and the cost is low. Mainly including silicone oil, silicone grease, floor wax, and room temperature vulcanized silicone rubber.

(5) Composite insulators. Light weight, high mechanical strength, good anti pollution flashover performance, hydrophobicity, high pollution flashover voltage, long cleaning cycle, and self-cleaning properties. The disadvantage is that synthetic insulators are expensive, bear low radial and perpendicular stress to the centerline, and silicone rubber has a relatively soft texture, which is easy to damage and damage the sealing performance, resulting in a decrease in insulation performance.

Autumn inspection, also known as autumn maintenance. It is a seasonal routine and important work of the State Grid of China and other power systems, which will thoroughly address the safety hazards exposed during the peak summer season, in order to actively prepare for the power grid's peak winter season and conduct a comprehensive and planned "physical examination" of equipment. Transmission lines and power equipment have been exposed to the outside for a long time, and after experiencing long-term high temperature and heavy load operation, there are inevitably safety hazards for power equipment. The dirt attached to the insulation surface of electrical equipment gradually dissolves in water under humid conditions, forming a conductive film on the insulation surface, greatly reducing the insulation level of the insulator and causing strong discharge under the action of the power field. In order to avoid this phenomenon, our anti pollution flashover engineering protection is necessary, which is also a very important power protection measure for the annual spring and autumn inspection of the power system.

What is anti pollution flash coating? Anti pollution flashover coating is a special insulation coating for power systems, which is widely used in power systems due to its excellent anti pollution flashover performance. The hydrophobicity and migration of anti pollution flashover coating are the key to significantly improving the pollution flashover voltage level.

Anti pollution flashover coating is applied to the surface of electric porcelain bottles, and after curing, a layer of adhesive film is formed. The adhesive film has excellent hydrophobicity under clean conditions. When the surface of the adhesive film is covered by dirt, the small molecule hydrophobic groups inside the film can quickly pass through the dirt layer and migrate to the surface of the dirt layer, making the surface of the dirt layer also have excellent hydrophobicity. In this way, under humid weather conditions such as fog, dew, and drizzle, it is difficult to wet the surface of the pollution layer. If the pollution layer is kept moist for a long time, it will not form water flow and water film on the surface, but will exist independently as numerous discontinuous small water droplets, greatly suppressing the generation of leakage current and significantly increasing the pollution flashover voltage of insulators.

Instructions for the use of our anti pollution flash coating (RTV/PRTV)

The Guiding Principles for the Use of Anti Pollution Flashover Coatings for External Insulation of Transregional Power Grid Transmission and Transformation Equipment of the State Grid of China (Trial) have re standardized the PRTV long-term anti pollution flashover coating (including RTV coating), which is the highest standard level of national anti pollution flashover coating products. The product performance indicators meet all type test standards of this standard, and the main performance exceeds the standard value. Its performance characteristics include: ultra long aging, high resistance to electrical corrosion, high insulation and mechanical strength, high pollution flashover voltage, and other comprehensive functions, which can ensure the stable operation of external insulation of transmission and transformation equipment.

The product performance of our anti pollution flash coating (RTV/PRTV):

(1) Significantly increase the external insulation pollution flashover voltage of power transmission and transformation equipment, and increase its pollution flashover voltage to over 200%;

(2) This product is a single component and does not require mixing during use, ensuring quality and reducing waste. It is suitable for power outage or live spraying construction;

(3) The coating has hydrophobicity and hydrophobic migration characteristics, which can enhance the insulation resistance of the external insulation in a dirty and wet state;

(4) Under normal usage conditions, the external insulation of power equipment can be free from cleaning and maintenance, with a functional lifespan of over 15 years, thereby saving a lot of manpower and resources;

(5) This product has high resistance to electrical corrosion, dirt and moisture, and has reached a high level of resistance to leakage and marking, thus ensuring its resistance to electric ignition and high pollution flashover performance;

(6) The product has excellent insulation performance and can have flame retardant properties. If it is electrocuted, its residue is non-conductive, leaving no hidden dangers for equipment operation;

(7) The product has high mechanical strength, is suitable for wind and sand environment areas, and does not affect equipment maintenance work;

(8) The product has a certain degree of anti snow melting and anti icing effect, so it is also suitable for application in high cold areas;

(9) This coating is non flammable, non explosive, and not toxic to hazardous materials.

(10) High voltage electrical equipment with external insulation coated with this coating can undergo preventive testing normally. The testing method and results are not affected.

With the increasing severity of power pollution flashover, various types of coatings used for power pollution flashover are increasingly appearing in the market. Among them, anti pollution flashover coatings, as a common anti pollution flashover product, have an extremely important position in the market. No matter which type of power equipment, it needs to meet certain market needs in use, and anti pollution flashover has certain particularity in use, Maintaining its use also requires attention to many issues. Let's discuss and take a look together!

Firstly, there is the phenomenon of aging. For this type of anti pollution flash coating, due to the main body being silicone rubber and long-term exposure to the outside during use, the phenomenon of aging has become almost inevitable, coupled with the effects of ultraviolet radiation and electromagnetic fields. So it is important to pay attention to controlling the service life during use. Generally speaking, it is safer to use it within 5 years.

Secondly, it is the adhesion of anti fouling flash coating. Is the adhesion good or bad for this type of coating? When using, of course, we hope for greater adhesion to prevent detachment, but after using composite coatings, we also hope for less adhesion because it is easier to remove in the later stage. So the issue of adhesion is an area that needs to be focused on. Of course, there are many ways to remove coatings.

The third is the hydrophobicity of the coating. For anti pollution flashover coatings, hydrophobicity is a very important performance, and the improvement of the flashover voltage depends on the hydrophobicity of this coating. Generally speaking, the criterion for determining hydrophobicity is mainly based on whether the hydrophobicity angle of water droplets on the cornea is greater than 90 degrees. For example, the larger the angle, the shorter the migration time and the lower the probability of line failure.

With the increasing variety in the paint industry, the scope of general application is also becoming more and more extensive. We all know that the continuous rapid development of China and the world economy is also causing increasingly serious air pollution. Therefore, the continuous increase in rainwater or salinity has a certain impact on the paint on the outer end of buildings. In such a situation, the natural accumulation of dirt on the exterior of outdoor equipment in the power system is increasing. In such a situation, anti pollution flashover coatings can be chosen to achieve this protective effect.

There are various types and characteristics of anti pollution flash coating models, and the composition is mainly composed of trichloroethylene and tetrachloroethylene. The application of such organic composite materials has a prominent protective effect on outdoor equipment in the power system. In this situation, the widespread use of this coating is becoming increasingly diversified, improving its technological advantages and recognition in the industry, which is why it plays a crucial performance role in the industry.

Anti pollution flashover coating is a widely used new type of material, and the use of any new building material has a hard requirement of cost-effectiveness. It is naturally important in various bidding and tendering processes, which to some extent affects the final cost and even the success of the bidding process. In daily life, almost all products, their users will consider the issue of cost-effectiveness, and cost-effectiveness sometimes becomes the only requirement of any product.

The antifouling flashover coating has been added with some nano level high insulation reinforcement materials, so that it has high mechanical strength and adhesion, can withstand the erosion of strong wind and sand climate (for example, the area at the tuyere, electric locomotive, etc.), and meets the requirements of equipment maintenance pedal In particularly severe cases of pollution (such as due to the coverage of a large amount of dust pollution, although the coating is not ineffective, the hydrophobicity is difficult to migrate to the outer layer of the pollution), necessary water flushing or cleaning can be carried out. The mechanical properties of the coating can reach the strength of the umbrella skirt sheath material of the composite insulator.

Anti pollution flashover coating is a new type of electrical functional material specially designed for the power grid and various power generation, transmission, and consumption customers to permanently and completely eliminate the hidden danger of equipment pollution flashover.

Electrical equipment that is exposed to the outdoors for a long time is easily affected by the environment, and its insulation level can easily decrease in extreme cases, leading to electrical insulation failures. Therefore, improving the insulation performance of outdoor electrical equipment in different environments has become one of the main concerns of electrical equipment maintenance personnel. In recent years, anti pollution flashover coatings have been a new material used to improve the insulation level of electrical equipment, and have been rapidly developed and widely used in China due to their outstanding characteristics such as long-term effectiveness and maintenance free.

The production materials of anti pollution flashover coatings have hydrophobicity and unique hydrophobicity migration characteristics, which means that the hydrophobicity of materials can migrate to the surface of the dirt layer, and no continuous water film is formed on the coating surface of electrical equipment in severe weather (rain, fog, dew, drizzle). The coating surface has hydrophobicity, which can effectively prevent cement and chemical pollution from scaling on its surface, making it widely applicable to various natural and industrial environments. It has excellent insulation performance, excellent mechanical performance, strong adhesion, resistance to dust adhesion, corrosion, long service life, corona resistance, aging resistance, anti icing effect, and weather resistance.

The spraying work of anti pollution flash coating should be strictly carried out in accordance with its user manual. Before coating, moisture, oil stains, and other insulators should be cleaned up, and construction should also be carried out under meteorological conditions without rain, dew, or wind and sand. During construction, the metal parts at both ends of the equipment should be wrapped and protected. During spraying, protective measures should be taken to avoid affecting the operation of adjacent equipment. The implementation of coating spraying should be carried out after the insulation testing of electrical equipment is completed. Electrical equipment with unqualified insulation should be treated and replaced before coating spraying.

Insulators are mainly divided into three categories: porcelain insulators, glass insulators, and silicone rubber composite insulators. Porcelain insulators and glass insulators have wide applications in power grids and other power supply systems due to their good mechanical strength and easy cleaning and maintenance. However, due to the general hydrophobicity of the surface, discharge flashover is prone to occur when the pollution is severe and damp.

Based on the characteristics of glass and porcelain insulators, it is recommended to use high self-cleaning anti pollution flashover coating for anti pollution flashover treatment of insulators. High self-cleaning anti pollution flashover coating is a special anti pollution flashover coating developed specifically for high oil pollution and high pollution environments. It is based on ordinary anti pollution flashover coatings (RTV, PRTV), retains the original characteristics of the anti pollution flashover coating, and introduces organic fluorine monomers into the coating, The anti fouling flashover coating combines the hydrophobicity of organic silicon and the hydrophobicity of organic fluorine materials, making it a type of anti fouling flashover coating that is hydrophobic and oil repellent, prevents oil scale adhesion, and has good surface self-cleaning performance.

In order to overcome the situation where glass and porcelain insulators are prone to flashover due to surface contamination and moisture, a layer of hydrophobic anti flashover paint is usually sprayed on the surface of the insulators. Although ordinary anti flashover paint has good hydrophobicity, it is difficult to clean the surface after dust has accumulated, greatly increasing the difficulty of daily maintenance.

In response to the difficulty of dirt accumulation on the surface of the anti pollution flashover coating, which is difficult to clean after accumulation, it is recommended to use multi-functional insulator protective agent RS-80 for cleaning. After cleaning with multi-functional insulator protective agent, a semi permanent nano level protective film will be formed on the surface of the cleaned object, making the equipment shiny as new; It can also repair the surface of aged silicone rubber (anti pollution flashover coating, composite insulator) to achieve initial surface performance, with hydrophobicity and self-cleaning performance.

Room Temperature Vulcanized Silicone Rubber, abbreviated as RTV anti fouling flash coating, has been rapidly developed and widely used as a new technology and material in China in recent years due to its outstanding characteristics of long-term effect and maintenance free. In China, RTV coatings have undergone a development process of multi-component, dual component, and single component. After years of grid operation, single component RTV long-term anti pollution flashover coatings and single component PRTV ultra long effect anti pollution flashover coatings are mainly suitable for transmission and transformation equipment of various voltage levels below 750KV: suspension insulators (porcelain and glass), support insulators, switches, gates, lightning arresters, transformers, coupling capacitors, wall bushings, etc, And various porcelain components for indoor substation equipment in humid areas.

There are many types of anti pollution flashover coatings. Anti pollution flashover coating - PRTV (RTV - II) insulation flame retardant coating, as well as coating for reactor treatment, JY-1, DL-66 flame retardant thermal conductive coating, and reinforced anti pollution flashover coating PRTV. The raw material cost of PRTV anti pollution flash coating is 120 yuan/KG, and many 40/KG and 50 yuan/KG coatings in the market are definitely fake products. Electric power products involve personal and property safety, and there are many coatings sellers in the market. We must choose legitimate manufacturers to produce them, and we must be cautious in purchasing them.

During the use of power transmission equipment, due to environmental factors, many faults and problems have occurred in the entire circuit transmission equipment. This type of pollution flashover problem has caused widespread power outages nationwide, indicating that this type of problem cannot be underestimated. The traditional solution to such problems is to regularly clean the stains on the insulation terminals, which can have a significant impact on both human and financial resources during the anti pollution flashover process.

At present, many power transmission units ensure that insulation terminals can avoid accumulating a lot of stains through the use of high-quality coatings during the maintenance of lines. This type of coating uses very good hydrophobic organic substances, which can prevent stains from slipping off after being dissolved in water in rainwater or humid air, ensuring the early formation of an electric film layer on the insulation terminals and avoiding the occurrence of some accidents. We need to choose some of the best products in this type of anti pollution flashover product to ensure that these lines reduce unnecessary pollution flashover issues to a greater extent during daily operation.

This type of coating product needs to have some good advantages and properties. After spraying, it must have a good service life, and will not fall off during long-term use. It can also effectively resist acid and alkali pollutants caused by current severe atmospheric pollution. With the improvement of material technology and industrial technology, anti fouling flashover coatings have made the entire coating more effective and outstanding, significantly improving its service life.

With the changes of the times and the development of social productivity, more and more anti pollution flashover coatings are used. Of course, this is also due to the intensification of pollution. So what are the aspects of pollution?

Anti pollution flashover coating RTV (PRTV) pollution can be divided into two categories according to its source:

Category 1: Natural type pollution. Mainly sourced from natural environments such as oceans, swamps, and soil. Common pollutants include coastal seawater pollution, farmland dust pollution, saline alkali farmland pollution, and sandy soil pollution.

Category 2: Industrial pollution. This type of pollution mainly comes from various industrial production and the products of various forms of fossil fuel combustion. Common pollutants include general industrial pollution, chemical pollution, power plant pollution, metallurgical pollution, cement pollution, highway pollution, and so on.

So some people may ask, what are the common components of atmospheric pollutants and the impact of meteorology on environmental pollution?

The sediment pollution on the surface of insulators can be divided into many types according to the nature of the pollution sources in their respective regions, but they are all closely related to atmospheric pollution in various regions. According to information on atmospheric environmental pollution, the composition of pollutants in the atmosphere often varies due to different pollution sources, industrial raw materials, and processes, resulting in different emissions.

The common main components include sulfur oxides, nitrogen oxides, carbon oxides, hydrocarbons, and particulate matter.

Common particulate matter includes sulfates, nitrates, organic compounds, metals, and metal oxides.

These compounds in the atmosphere have a significant impact on the deposition of dirt on the surface of insulators. Meteorology is an important factor affecting environmental pollution. Wind direction, wind speed, temperature, pressure, cloud cover, rainfall, airflow, and humidity all directly affect pollutants. Air pressure, wind speed, and humidity directly affect the emission and diffusion of pollutants. The dominant source of pollution often accumulates more pollutants on the windward side and can be transported far away. Especially when the meteorological inversion layer appears, it often causes very serious atmospheric pollution.

    In the power system, the busbar is an important component for collecting, distributing and transmitting electric energy. It is a conductive connection point, usually made of copper or aluminum, which serves to connect generators, transformers, loads and other power equipment. The busbar is connected to other parts of the power system through power switches and protection devices to achieve the distribution and dispatch of electric energy.

1. The role of the busbar

1. Collecting electric energy: The busbar collects the electric energy from multiple generators or transformers together so that it can be transmitted and distributed through one or more lines.

2. Electric energy distribution: The busbar can distribute electric energy to multiple loads to ensure that electricity can be effectively delivered to various parts. It is the core part of the distribution system.

3. Simplify the system structure: Connecting multiple power equipment through the busbar reduces the complex line layout and simplifies the structure and maintenance difficulty of the power system.

4. Power dispatching: The busbar can dispatch power according to the needs of the system, such as switching different lines or loads to achieve flexible distribution of power.

5. Voltage control: The busbar is connected to a transformer or compensation device to maintain the voltage stability of the system, especially when power generation and load fluctuate.

2. Working principle of busbar

The working principle of busbar is to realize the collection and distribution of electric energy by connecting multiple power sources (such as generators or transformers) and loads (such as factories and houses) together. Power equipment is connected to the busbar through circuit breakers and disconnectors to realize the opening, closing and switching operations of the circuit.

The busbar usually works at high voltage, requiring it to have good conductivity and sufficient mechanical strength to withstand large currents. To ensure the reliability of the power system, the busbar is equipped with protection devices (such as circuit breakers, relay protection devices), which can quickly cut off the faulty part in the event of a fault to avoid large-scale power outages.

3. Types of busbar

Based on the structure and application, busbars can be divided into the following types:

1. Single busbar system:

- Structure: The single busbar system consists of a busbar connecting all generators, loads and power equipment.

- Advantages: simple structure, low cost, suitable for small power systems.

- Disadvantages: When a bus fails, the entire system may be out of power, and the reliability is low.

2. Double bus system:

- Structure: It consists of two busbars, each of which can independently connect the generator and the load, usually connected and switched through a bus coupler.

- Advantages: It has higher reliability. When one bus fails, the other bus can continue to supply power. It is suitable for large substations and occasions with high reliability requirements.

- Disadvantages: High cost and complex structure.

3. Bus segmentation system:

- Structure: The bus is divided into multiple parts, and each part is connected by a circuit breaker or bus coupler.

- Advantages: The bus segmentation system can isolate the fault area in the event of a fault, keep the rest of the parts running normally, and improve the reliability of the system.

- Disadvantages: More switchgear is required, which increases the cost and complexity of the system.

4. Ring bus system:

- Structure: The busbars in the ring bus system connect the generator and the load in a ring structure. The current in the system can flow in both directions.

- Advantages: It has better flexibility and redundancy. When a part fails, it can continue to supply power from another direction.

- Disadvantages: The design is relatively complex and the cost is high. It is suitable for ultra-high voltage transmission systems.

5. Breaker-and-a-Half Scheme:

- Structure: It consists of three circuit breakers and two busbars. The load and power generation equipment are connected between the two circuit breakers respectively, and the busbar is divided into two independent lines.

- Advantages: The system provides high redundancy and flexibility. Even in the event of a fault, power can still be supplied through another busbar. It is widely used in large-capacity substations.

- Disadvantages: The design and cost are relatively high, and the operation and maintenance are relatively complex.

    The busbar plays the role of collecting, distributing and dispatching electric energy in the power system. According to the needs and scale of the system, the busbar can have different structures, such as single busbar, double busbar, busbar segmentation, ring busbar and circuit breaker half busbar system. Different types of busbar systems have their own advantages and disadvantages. Choosing a suitable busbar structure can improve the reliability, flexibility and safety of the power system.

Overvoltage refers to the voltage value in the power system exceeding the allowable range of its rated voltage. Overvoltage can have a serious negative impact on power equipment, system stability and power users, and may even cause accidents such as equipment damage and power outages. Therefore, it is crucial to understand the classification of overvoltage, its impact on the power system and effective preventive measures.

1. Classification of overvoltage

Overvoltage is usually divided into the following types according to its cause and duration:

1. External overvoltage:

- Definition: Overvoltage caused by external factors, usually caused by natural factors such as lightning.

- Characteristics: The amplitude of external overvoltage is very high, usually short-term (milliseconds or microseconds), and transient overvoltage often occurs during lightning strikes.

- Source:

- Lightning overvoltage: When lightning directly or indirectly hits power equipment or lines, the resulting current fluctuations cause a sudden increase in voltage.

- Induced overvoltage: When lightning strikes the ground or other conductors at a distance, it induces high voltage on the power line.

2. Internal overvoltage:

- Definition: Overvoltage caused by operation or failure within the power system.

- Characteristics: The amplitude of internal overvoltage is usually low, but the duration is long.

- Source:

- Operation overvoltage: Voltage fluctuation caused by switch operation or power system switching, such as closing and opening operation of circuit breakers or disconnectors.

- Arc grounding overvoltage: When the neutral point of the power system is not grounded or high-resistance grounded, a single-phase grounding fault will cause a high-amplitude voltage fluctuation.

- Resonance overvoltage: Electromagnetic resonance occurs in the inductive and capacitive components (such as reactors and capacitors) in the system, resulting in voltage increase.

3. Transient overvoltage:

- Definition: Temporary voltage increase, usually for a short time (microseconds to milliseconds).

- Source: Transient overvoltage generated by lightning strikes, power equipment operation, fault clearing, etc.

4. Long-term overvoltage:

- Definition: System voltage continues to be higher than the rated voltage for a long period of time (seconds to hours).

- Source: Failure of voltage regulator, improper grid operation parameters, etc.

2. Impact of overvoltage on power system

Overvoltage will have a series of adverse effects on power system and its equipment, including:

1. Damage to electrical equipment:

- Overvoltage may cause insulation breakdown of electrical equipment, such as insulation system of transformers, circuit breakers, cables and other equipment, leading to short circuit or damage of equipment.

2. Overheating and aging of equipment:

- Overvoltage will cause excessive current to flow through power equipment, causing equipment overheating, accelerating aging of insulation materials and shortening equipment service life.

3. Malfunction of protection equipment:

- Overvoltage may cause malfunction of protection equipment (such as relay protection device), leading to system tripping or frequent power outages, affecting the continuity and reliability of power supply.

4. Power quality issues:

- Overvoltage will cause voltage fluctuations and affect the normal operation of user equipment. Sensitive equipment such as computers, automatic control systems, etc. may fail due to overvoltage.

5. Arcing and fire:

- Overvoltage may cause arc discharge between high-voltage lines or equipment, and even cause fire in severe cases.

3. Measures to prevent overvoltage

To prevent and alleviate the impact of overvoltage on the power system, common measures include the following aspects:

1. Lightning arrester (lightning rod, lightning conductor):

- Function: used to protect against external lightning overvoltage. Lightning arrester can lead lightning to the ground, reduce the direct entry of lightning current into the power system, and thus prevent overvoltage caused by lightning.

- Application scenario: widely used in high-voltage substations, power plants and transmission lines.

2. Arc suppression coil:

- Function: Arc suppression coil is used to limit arc grounding overvoltage. When a single-phase grounding fault occurs in the power system, the arc suppression coil can compensate for the inductive current in the system and avoid the reignition of the arc.

- Application scenario: suitable for power systems with ungrounded neutral points or grounded through arc suppression coils.

3. Overvoltage protector:

- Function: Installing an overvoltage protector can quickly divert excessive voltage fluctuations when overvoltage occurs in the system, protecting the equipment from overvoltage.

- Application scenario: suitable for various power equipment, such as transformers, generators, etc.

4. Optimization of power system operation:

- Measures: Avoid frequent operation of power equipment, especially unplanned switching operation. Minimize the frequent operation of the switching circuit to prevent the generation of operational overvoltage.

5. Install parallel capacitors:

- Function: By installing parallel capacitors, the power factor can be improved, the voltage level can be adjusted, and the occurrence of overvoltage can be avoided. At the same time, the reactive power transmission in the power system can be reduced, thereby reducing the resonance overvoltage.

6. Resonance inhibitor:

- Function: When resonance may occur in the system, the resonance inhibitor can eliminate or weaken the resonance phenomenon and avoid the generation of resonance overvoltage.

7. Adjust system operating parameters:

- Measures: Ensure that the system's voltage regulator and automatic voltage control device work properly, reasonably adjust the excitation current of the generator and transformer, and keep the system voltage within the rated range.

IV. Summary

Overvoltage is a common and destructive phenomenon in power systems, which may be caused by lightning strikes, operating errors or system failures. Overvoltage can cause problems such as damage to electrical equipment and system instability. By installing lightning arresters, arc suppression coils, overvoltage protectors and other equipment and taking reasonable operating measures, the impact of overvoltage on the power system can be effectively prevented.