How to detect high voltage zinc oxide surge arresters

The impact of lightning on high-voltage lines is very large, so many high-voltage lines are equipped with zinc oxide surge arresters, and aging will occur after a long time. How to quickly and accurately detect the zinc oxide surge arresters has become very important.

Lightning strike is the main cause of line tripping

The lightning strike circuit forms a voltage wave, propagates along the circuit and invades into the transformer—damaging the formation of the substation equipment.

According to the physical process of overvoltage formation, the overvoltage needs to be divided:

1 direct lightning over-voltage - hit the tower, lightning conductors or wires, causing line over-voltage - great harm.

2 magnetic induction over-voltage - lightning strike line near the earth, due to electromagnetic induction over the wire caused by over-voltage 35KV line following a threat.

Direct lightning overvoltage two types

Counterattack: When a lightning strikes a line tower or a lightning conductor, the lightning current passes through the lightning strike point impedance, which greatly increases the potential of the point. When the potential difference between the lightning strike point and the conductor exceeds the line isolation surge voltage, flashover occurs to the conductor. Make the wire overvoltage. At this time, the potential of the tower or the lightning conductor will be higher than the wire, so it is called counterattack.

Breaking: Lightning current hits the conductor directly (no lightning conductor) or bypasses the lightning conductor (shield failure). The conductor hits the conductor and causes an overvoltage directly on the conductor. This is called a bypass stroke.

Lightning overvoltage consequences

1 Short-circuit grounding - After the wire is flashed to ground, the power-frequency voltage is discharged along the channel and sent to the power-frequency arc ground to trip the circuit breaker. Affects normal power transmission.

2 The formation of lightning waves that invade and transform the circuit along the transmission line, complex sub-reflection processes occur in the substation—the power equipment withstands high voltage—the insulation blackout of the equipment is destroyed.

Transmission line lightning protection performance measurement index

Lightning resistance level - The maximum lightning current amplitude that a line can withstand without causing a flashover.

Lightning Strike Tripping Rate—Converting the standard condition for a lightning factor of 40 last year The number of line trips per hundred kilometers of line caused by lightning strikes per year (times per hundred kilometers) – a measure of compliance.

ZGF-H series DC high voltage generator is suitable for DC voltage withstand test and leakage current test of high-voltage electrical equipment such as zinc oxide surge arresters, power cables, generators, transformers, and short-circuiting devices.

Use computer control technology to control PWM pulse width modulation, measurement, protection and display, display output DC high voltage, current, overvoltage setting, timing and protection information on large screen LCD display, and communicate with computer with RS232 interface .