Procedura testowania uszkodze\u0144 uziemienia-Things to Keep in Mind During Testing:<\/strong><\/h2>\n\n\n\nFirst, do the complete field acceptance testing as required by the NEC.<\/p>\n\n\n\n
Secondly, check the neutral main bonding connection.<\/p>\n\n\n\n
Thirdly, check for any improper installation in a sensor and grounding connections.<\/p>\n\n\n\n
Once you inject current through the current sensor, make a note of the pickup and timing of the relay.<\/p>\n\n\n\n
Reduce current voltage supply to 277 from 480.<\/p>\n\n\n\n
Finally, check whether special features like zone interlocks are working properly.<\/p>\n\n\n\n
Ground Fault Guard System Testing Methods <\/em><\/strong><\/p>\n\n\n\nThere are two test methods for assessing ground fault protection systems:<\/p>\n\n\n\n
Procedura testowania uszkodze\u0144 uziemienia-Simulated Fault Current Method<\/strong><\/h3>\n\n\n\nTesting using a helps to identify the effectiveness of the relay. Further, you also understand the functioning of the sensor and shunt trip. Additionally, you can verify the competence of the control power supply. When you wind a coil around a window-type sensor, it creates a simulated fault current. Once a current passes through the test winding, it creates a secondary current in the sensor. The relay responds in the same way it would respond to a primary current of 1600 amperes.<\/p>\n\n\n\n
High-Current Primary Injection Method<\/strong><\/h3>\n\n\n\nThe high-current primary injection method tests the reliability of all the system components. This includes the circuit breaker operation, relay or trip unit, control power, wiring, and the current transformers.<\/p>\n\n\n\n
In this, you inject a high-current supply through the primary side of the overcurrent device or current transformer. This will duplicate the flow of ground-fault current under various conditions.<\/p>\n\n\n\n
Zero-Sequence Earth Fault Protection Systems- Performance Testing<\/strong><\/h2>\n\n\n\nBefore performance testing, perform a visual inspection. Ensure that the number of neutral conductors and phase conductors passing through the zero-sequence sensor is correct. Further, make sure that the direction of the conductor is right.<\/p>\n\n\n\n
You can conduct these tests to verify the correct operation of zero-sequence ground fault protection systems:<\/p>\n\n\n\n
No Trip Test<\/strong><\/h3>\n\n\n\nIn this, make sure that the phase conductor and neutral conductors go in a similar direction through the sensor. Connect the supply to points N1 and A1 to a jumper that connects N2 and A2. The main breaker will not trip even when the test current goes beyond the preset pickup and trip time.<\/p>\n\n\n\n
Image: zero-sequence ground fault- no trip test<\/em><\/p>\n\n\n\n