>> Traditional Method: Sectionalization
Traditional ways of fault location in DC system involves sectionalization or interruption of DC branches to isolate the ground fault. This method will disable system protection and will cause system lines and generator tripping. For this reason, many utilities have banned sectionalization, and DC ground fault has to be located ONLINE.
>> Better Method: Current Injection
A better test method will inject a low-frequency AC signal and use this AC signal to locate the ground fault in the DC system. This method can be performed when system is online without sectionalizing the DC system and it reduces the fault locating time.
Advantage: Injection of higher current signal to quickly locate the fault.
Disadvantage: Injection of high current signal will cause relay tripping in some DC systems. Also, distributed capacitance can greatly affect the fault location.
>> Improved Method: Use Measurement Bridge
For online fault location, there are 2 things to avoid: interference by distributed capacitance and system safety causing relay tripping.
To do this, our updated models of ground fault locator adopt the measurement bridge inside the signal analyzer to analyze voltage, current and grounding resistance.
No injection of current signal to tested system and no relay tripping. It is more effective for fault location and safe to the tested circuits.
Click HERE to view more info about Kongter’s solution using new methods.