Deep analysis of the selection of arresters for different voltage levels

2025-07-19 12:49:04

The following is a deep analysis of the selection of arresters for different voltage levels, covering the differences in core parameters, selection formulas, and typical error cases, to help you avoid technical traps

I. Core Parameter Weights of Lightning Arresters of Different Voltage Levels

Ii. Parameter Benchmarking Table: Qualified vs. Incorrect Selection

Scene, qualified selection,  incorrect selection, consequences

The residual voltage of the 10kV distribution network YH5WZ-17/45 and YH1W-17/50 is too high and breaks down the insulation of the transformer

Insufficient current flow at the 110kV substation Y10W1-108/268W and Y5WZ-108/281 caused an explosion

Thermal collapse of 500kV lines Y20W1-444/1066 and Y10W-444/995 due to insufficient energy absorption

Iii. Golden Rules for Selection

1. Distribution network lightning arrester: Three verification principles

A[System Grounding Method] --> Neutral point ungrounded; B[Select continuous operating voltage ≥1.1Um]

A --> Neutral point grounding C[Select ≥0.8Um]

D[altitude] --> 1000m E[Correction factor K=1+0.001(H-1000)]

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2. Substation lightning arrester: Four-step method for current flow

Calculate the maximum short-circuit current $I_{sc}$

2. Select $I_{min}=1.3I_{sc}$

3. Verify the pressure release rating (40kA/63kA)

4. The composite jacket needs to pass the 1000-power wave impact test

3. Ultra-high Voltage lightning arrester: Double energy insurance

- Energy margin: Design value ≥ 1.5 times the measured maximum impact energy

- Current sharing check: When multiple columns are connected in parallel, the current unbalance degree is less than 5%

Iv. Engineering Counterexample Warnings

Case 1: The residual voltage ratio of the distribution network exceeds the standard

- Scene: A 10kV wind farm along the coast

- Error: A common type lightning arrester (residual voltage ratio 3.2) was selected.

Consequence: During the typhoon season, 22 box-type transformers were burned out because $U_{res}=39kV > the equipment's withstand voltage was $35kV$

Case 2: Insufficient current-carrying capacity of the substation

- Scene: 110kV mine substation

Error: Short-circuit current increased to $24kA$(original design $18kA$) was not taken into account.

Consequence: Overvoltage caused by the tripping of the circuit breaker led to the explosion of the three-phase lightning arrester

Case 3: Omission in ultra-high voltage energy calculation

- Scene: 500kV hydropower transmission project

- Error: Long-tail operation overvoltage (duration > 3000μs) was not included.

Consequence: Energy overload caused the lightning arrester column to burst, and the line was shut down for two weeks

> Pitfall Avoidance summary: Selection must follow the "scenario - parameter - verification" triple matching:

> - Distribution Network: Strictly control residual pressure ratio + crawling distance (refer to DL/T 804)

> - Substation: Strictly adhere to current capacity + pressure release (in compliance with GB 11032)

Ultra-high voltage: Focused energy design + Voltage Equalization Verification (refer to IEC 60099-4)

Remember: Additional coefficient corrections are required in high-altitude, heavily polluted, and strongly vibrating scenarios!