Analysis of Isolating Switch Applications in Generator Neutral Grounding Resistor Cabinets

Application of Isolating Switches in Generator Neutral Grounding Resistor Cabinets

Isolating switches are commonly installed in NS-FZ generator neutral grounding resistor cabinets. They provide a clearly visible disconnection point, ensuring the safety of maintenance and testing personnel. However, as high-voltage devices without arc-quenching capability, isolating switches must only be operated when the circuit is de-energized—i.e., under no-load conditions.

The primary function of an isolating switch is to isolate the power source for maintenance purposes and to perform no-load switching of circuits. When used in coordination with circuit breakers, it enables flexible reconfiguration of system operation modes, enhancing overall reliability and operational flexibility.

Isolating switches may be used to make or break small-current circuits with limited capacitive or inductive loads, such as:

(a) Circuits of voltage transformers and surge arresters
(b) No-load transformer circuits with magnetizing current not exceeding 2 A
(c) No-load transmission lines with capacitive current not exceeding 5 A
(d) Capacitive currents of busbars and equipment directly connected to them
(e) The grounding conductor and grounding resistor cabinet at the transformer (or generator) neutral point