The 220kV power station type Lightning Arrester is an important protective equipment in the power system, and its performance directly affects the safe and stable operation of the power grid. To help you quickly understand its core indicators, the following table summarizes the key parameters and their interpretations.
Key parameters | Typical values/ranges | Interpretation of parameter meanings and selection |
Rated voltage | 200 kV | Lightning arrester design reference refers to the voltage at which it can reliably operate under specified loads. The selection should be based on the maximum voltage and grounding method of the system, for example, for neutral point non directly grounded systems, the rated voltage should be appropriately increased. |
Continuous operating voltage | 156 kV | The effective value of the power frequency voltage allowed to be applied to both ends of the lightning arrester for a long time, which must be higher than the maximum phase voltage of the system. |
The nominal discharge current | 10 kA | represents the discharge capacity level of the lightning arrester, and the 220kV system usually uses the 10kA level. |
DC 1mA reference voltage | ≥ 290 kV | is a key parameter for measuring the nonlinear characteristics and aging status of lightning arrester valve plates. This value needs to remain stable, and a significant decrease during operation indicates that the valve plate may be aging. |
Residual voltage (lightning impulse/operational impulse/steep wave) | ≤ 520 kV/≤ 442 kV/≤ 582 kV | The core protection indicator is the peak residual voltage at both ends of the lightning arrester under the impulse current. There may be different requirements depending on the application location (such as outgoing surge arresters, incoming surge arresters, and busbar surge arresters). The residual voltage value must be lower than the insulation withstand level of the protected equipment. For example, the residual voltage under the nominal discharge current of the valve type lightning arrester should not exceed 71% of the standard lightning impulse full wave withstand voltage of the protected electrical equipment. |
Creepage distance | ≥ 7812 mm (calculated based on IV level pollution of 31mm/kV) | Guarantee of external insulation anti pollution flashover capability. The selection should be based on the pollution level of the installation area, with higher requirements for Class IV heavily polluted areas. |
Deep analysis of key parameters
In addition to the basic information in the table, understanding the following in-depth technical points can help you better select and evaluate.
-The synergy between rated voltage and continuous operating voltage
The rated voltage (Ur) is the maximum effective value of the power frequency voltage that the lightning arrester can meet for the action load test. Continuous operating voltage (Uc) is the effective value of the power frequency voltage that allows for long-term continuous operation. For neutral point non directly grounded systems, due to single-phase grounding faults, the operating time can reach 2 hours. The rated voltage should be selected at 1.2-1.3 times the maximum system voltage to prevent the lightning arrester from thermal collapse under transient overvoltage. The continuous operating voltage is usually taken as the highest line voltage of the system.
-Residual voltage level and equipment insulation coordination
Residual voltage is a direct reflection of the ability of lightning arresters to limit overvoltage and protect equipment. The protection level of lightning arrester is determined by its residual voltage. Taking the 220kV system as an example, the lightning impulse withstand voltage of the transformer is usually 950-1050kV. If the lightning residual voltage of the lightning arrester is ≤ 520kV, the coordination coefficient is 950/520 ≈ 1.83, which is greater than the standard requirement of 1.4, indicating effective protection. The residual voltage requirements for lightning arresters in different locations (such as outgoing lightning arresters and incoming and bus lightning arresters) may vary. For example, outgoing lightning arresters may have higher residual voltage limits due to the need to withstand more severe lightning impacts.
-DC reference voltage and leakage current
The reference voltage of 1mA DC (U1mA) mainly reflects the moisture and aging condition of the valve plate. Measure the leakage current at 0.75 times U1mA voltage to monitor its resistive component. The regulations require that the leakage current of the lightning arrester during operation should not exceed twice the initial value of operation. An increase in resistive current usually indicates a decrease in the insulation performance of the valve plate or internal moisture, which is a key condition maintenance indicator that needs to be closely monitored.
Selection and Benchmarking Points
In actual selection and technical benchmarking work, in addition to checking the parameter table, attention should also be paid to the following points:
-Clarify application scenarios and standards: Firstly, confirm whether the lightning arrester is used in power stations, distribution systems, or other systems, and follow the corresponding national standards (GB) and industry standards, such as GB11032 "Metal Oxide Surge Arresters without Gap for AC Systems" as the basic standard.
-Pay attention to structural design and environmental adaptability
-Insulated jacket: Composite jackets (such as silicone rubber) have the advantages of light weight, explosion resistance, pollution resistance, and shock resistance, and are currently the mainstream trend.
-Sealing performance: Poor sealing can lead to internal moisture failure. High quality lightning arresters require extremely low leakage rates, such as less than 4.43 × 10 ?? Pa · L/s.
-Pollution resistance: Select sufficient creepage distance according to the pollution level of the installation area. For Class IV heavily polluted areas, it is usually required to be no less than 31mm/kV.
-Consideration of special working conditions
-High altitude correction: When the altitude exceeds 1000m, the air density decreases and the external insulation strength decreases, requiring special design or correction.
-Short circuit current capability: Surge arresters should have pressure release capability to ensure safe energy release and prevent explosions in the event of a short circuit fault in the system.
I hope this detailed parameter analysis and benchmarking guide can help you gain a deeper understanding of 220kV Power station type lightning arresters and provide support for your selection and evaluation work. If you have further questions about specific application scenarios or more detailed parameters, we would be happy to continue discussing with you. http://www.helenlavette.com/page/contact-us.html
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