Use of ground protection of energy reducing maintenance switch (ERMS) for protecting controlgears

1 . A ground protection of an energy reducing maintenance switch (ERMS) system for protecting a controlgear, the ground protection of the ERMS system comprising:

a feeder comprising:

switchgears comprising a low voltage (LV) switchgear and a medium voltage (MV) switchgear,

a circuit breaker operatively connected to the switchgears,

wherein the circuit breaker comprises a trip coil;

a transformer operatively connected to the circuit breaker, and

a booster operatively connected to the LV switchgear;

the controlgear operatively connected to the feeder; and

a microprocessor protection relay, the microprocessor protection relay comprising:

a built-in ERMS with ground protection,

wherein the microprocessor protection relay is operatively connected to the circuit breaker and the controlgear,

wherein the microprocessor protection relay operates the built-in ERMS with ground protection during a pre-flashover phase by energizing the trip coil to activate the circuit breaker,

wherein, in the pre-flashover phase, a ground fault starts in the controlgear, and

wherein the circuit breaker operates to interrupt a current to the controlgear before any flashover occurs in the controlgear.

2 . The ground protection of the ERMS system according to claim 1 , wherein the controlgear comprises an attached controlgear and a standalone controlgear.

3 . The ground protection of the ERMS system according to claim 2 , wherein the circuit breaker comprise a tie circuit breaker, an incomer circuit breaker, and a feeder circuit breaker.

4 . The ground protection of the ERMS system according to claim 3 , wherein the incomer circuit breaker is operatively connected to the attached controlgear and a secondary side of the transformer.

5 . The ground protection of the ERMS system according to claim 3 , wherein the tie circuit breaker is operatively connected to the attached controlgear and the LV switchgear.

6 . The ground protection of the ERMS system according to claim 3 , wherein the feeder circuit breaker is operatively connected to the standalone controlgear and the LV switchgear.

7 . The ground protection of the ERMS system according to claim 3 , wherein the microprocessor protection relay comprises:

a microprocessor configured to:

perform timing and control of the ground protection of the ERMS system, and

carry out arithmetic and logical operations of the ground protection of the ERMS system;

a memory configured to store a program and data relevant to a specific task;

a graphical user interface (GUI) configured to transfer data and control signals to and from the ground protection of the ERMS system;

a bus system configured to permit communication of:

the microprocessor with the memory, and

the microprocessor with the GUI; and

an electronic circuit comprising high-impedance fault (HIF) detection element to detect small current ground faults, built-in impedance-based fault location, built-in metering and monitoring functions for post-fault diagnostics.

8 . The ground protection of the ERMS system according to claim 7 ,

wherein upon detecting and locating the ground fault in the controlgear, the microprocessor:

activates the built-in ERMS with ground protection,

trips the circuit breaker, and

deactivates the built-in ERMS with ground protection once the ground fault is cleared to adjust back protection speed; and

wherein during maintenance in the controlgear, an operator:

activates the built-in ERMS with ground protection,

trips the circuit breaker; and

the operator deactivates the built-in ERMS with ground protection operator once the maintenance is completed to adjust back protection speed.

9 . The ground protection of the ERMS system according to claim 8 ,

wherein upon detecting and locating the ground fault in the attached controlgear, the microprocessor trips the incomer circuit breaker and the tie circuit breaker; and

wherein during maintenance of the attached controlgear, the operator trips the incomer circuit breaker and the tie circuit breaker.

10 . The ground protection of the ERMS system according to claim 8 ,

wherein upon detecting and locating the ground fault in the standalone controlgear, the microprocessor trips the feeder circuit breaker; and

wherein during maintenance of the standalone controlgear, the operator trips the feeder circuit breaker.

11 . A method of ground protection of energy reducing maintenance switch (ERMS) system for protecting a controlgear, the method comprising:

connecting the controlgear to a feeder, wherein the feeder comprises:

switchgears including a medium voltage (MV) switchgear and a low voltage (LV) switchgear,

a circuit breaker operatively connected to the switchgears,

wherein the circuit breaker comprises a trip coil;

a transformer operatively connected to the circuit breaker, and

a booster operatively connected to the LV switchgear;

connecting a microprocessor protection relay, comprising a built-in ERMS with ground protection, to the the circuit breaker and the controlgear;

operating, using the microprocessor protection relay to energize the trip coil to activate the circuit breaker, the built-in ERMS with ground protection during pre-flashover phase, wherein ground fault starts in the controlgear during the pre-flashover phase; and

operating the circuit breaker to interrupt a current to the controlgear before any flashover occurs in the controlgear; and

deactivating the built-in ERMS with ground protection once the ground fault is cleared to adjust back protection speed.

12 . The method according to claim 11 , wherein the controlgear comprises an attached controlgear and a standalone controlgear.

13 . The method according to claim 12 , wherein the circuit breaker comprises an incomer circuit breaker, a tie circuit breaker, and a feeder circuit breaker.

14 . The method according to claim 13 , further comprises connecting the incomer circuit breaker to the attached controlgear and a secondary side of the transformer.

15 . The method according to claim 13 , further comprises connecting the tie circuit breaker to the attached controlgear and the LV switchgear.

16 . The method according to claim 13 , further comprises connecting the feeder circuit breaker to the standalone controlgear and the LV switchgear.

17 . The method according to claim 13 , further comprises:

timing and controlling the ERMS system by a microprocessor of the microprocessor protection relay;

carrying out arithmetic and logical operations of the ERMS system by the microprocessor;

storing a program and data relevant to a specific task by a memory of the microprocessor protection relays;

transferring data and control signals to and from the ERMS system by a graphical user interface (GUI) of the microprocessor protection relay;

permitting communication of:

the microprocessor with the memory, and

the microprocessor with the GUI;

detecting small current ground faults by high-impedance fault (HIF) detection element;

locating ground faults by built-in impedance-based fault location; and

metering and monitoring ground faults by built-in metering and monitoring functions.

18 . The method according to claim 17 , the method further comprises:

upon detecting and locating the ground fault in the controlgear:

activating the built-in ERMS with ground protection by the microprocessor,

tripping the circuit breaker by the microprocessor,

deactivating the built-in ERMS with ground protection by the microprocessor once the ground fault is cleared to adjust back the protection speed;

during maintenance in the controlgears:

activating the built-in ERMS with ground protection by an operator,

tripping the circuit breaker by the operator; and

deactivating the built-in ERMS with ground protection, by the operator, once the maintenance is completed to adjust back protection speed.

19 . The method according to claim 18 , further comprises:

tripping the incomer circuit breaker and the tie circuit breaker, by the microprocessor, upon detecting and locating the ground fault in the attached controlgear; and

tripping the incomer circuit breaker and the tie circuit breaker, by the operator, during maintenance of the attached controlgear.

20 . The method according to claim 18 , further comprises:

tripping the feeder circuit breaker, by the microprocessor, upon detecting and locating the ground fault in the standalone controlgear; and

tripping the feeder circuit breaker, by the operator, during maintenance of the attached controlgear.