Arrester Fault Indicator

Arrester fault indicator
1. Purpose
Arrester fault indicator (hereinafter referred to as an indicator) for indicating faulty arrester. When the arrester fault indicator wafting ribbon, indicating that the surge arrester is damaged.
2.The technical parameters
ZSQ-1 arrester the main technical requirements for the malfunction indicator, the arrester is normal, not action (ribbon not smell). When the arrester fault action should be accurate, wafting ribbons. When the lightning arrester is subjected to impact or high current operation overvoltage shock does not operate. When the arrester withstand power frequency voltage, the indicator should not be action. Technical Specifications Table 1 below:
Table 1: arrester fault indicator Technical parameters

3 .The indicator works
35KV and the following system for the center of the insulation system. When the arrester fails, the internal breakdown lightning damage, short-circuit fault. But because the system is central store insulation, flowing short-circuit current fault arrester relatively robust capacitive currents. According to statistics change current is generally about 10-20A, then the system showed a single-phase operation mode. This operating mode current flows shown in Figure 1:

Figure 1: Single-phase operation mode current flow diagram
Ua, Ub, Uc voltage three-phase system. Ca as A phase conductors to ground the equivalent capacitance, Cb is B phase conductors equivalent capacitance to ground. Since the C-phase arrester internal fault has shorted to ground, C relative capacitance Cc has no equivalent. A relatively ia as capacitive currents, ib relative to B capacitive currents, iab flowing through the insulator capacitive fault current that is phase to ground fault currents, the size of 10-20A. The same principle, the ground current A-phase or B-phase arresters damaged and iab size is the same.
Electronic schematics indicator shown in Figure 2: Indicators sampling current transformer (CT) in series with the anti-off insulator current loop when the arrester fails, the fault current is sensed current transformer input control circuit, a control circuit determine the fault current magnitude and duration, when the magnitude of the fault current reaches the set value, and can continue for some time, the control circuit determines the arrester is damaged and the output voltage to an electrically actuated ignition blasting, electronically controlled blasting detonator, color warning tape wafting. Indicates that the surge arrester is damaged, the accident point to look for a great convenience, significantly reducing the exclusion of the accident’s time to make the system operational as soon as possible to restore security.

Figure 2: Indicators of electrical schematics
Since the current is small, lightning cracking does not occur, there is no significant external changes. The failure to exclude increased the difficulty, after when installation indicator.
For high-voltage arrester, such as the above 110KV arrester leakage current when lightning damage increasing, when after a workout reaches a certain value, an indicator burst open, while the arrester ground wire is disconnected to prevent lightning arrester explosion, resulting in greater accident.