Directional over-current ground relay (DOCGR) using sampled value and method for operating the DOCGR
AssigneeLsis Co., Ltd.
InventorSu-Hyeong Jang
Life of this patent
Estimating the term…
Abstract
The present disclosure relates to a directional over-current ground relay (DOCGR) for performing a protective relay of the power source system such as a micro-grid system using communications between an SV-remote terminal unit (SV-RTU) and the DOCGR, wherein the SV-RTU is configured for measuring voltage and current of the distributed power source system and thus generating a sampled value (SV) signal. Further, the present disclosure relates to a method for operating the DOCGR.
Claims11
A distributed power source system comprising:
- a power supply for supplying power;
- a distributed generation (DG) for supplying generated-power using distributed power sources connected to a power grid;
- a plurality of loads for consuming power supplied from the power supply and the distributed generation (DG);
- a plurality of directional over-current ground relays (DOCGRs) provided between the power supply and the distributed generation (DG) and using a sampled value (SV) signal, wherein each of the plurality of directional over-current ground relays (DOCGRs) trips a corresponding circuit breaker (CB) to isolate a faulty section in an event of a short-circuit or ground fault in a load-connected electric line connected thereto;
- and
- a SV-remote terminal unit (SV-RTU) for detecting a current value in the load-connected electric line located between the power supply and the distributed generation (DG) and for transmitting, to the directional over-current ground relays (DOCGRs), the detected current value and information about a location of the load-connected electric line.
A method for operating a directional over-current ground relay (DOCGR) using a sampled value, the method comprising:
- (a) acquiring voltage and current data in a load-connected electric line to the DOCGR, and receiving a sampled value (SV) signal including current data and location information detected by a SV-RTU;
- (b) using a signal processor to perform a DOCGR (Directional Over-current Ground Relay) operation based on the acquired voltage and current data (Main CT) in the electric line and the received SV signal (aux CT);
- (c) when it is determined from a calculation result by the signal processor based on the acquired voltage and current data (Main CT) that the electric line is in a fault state, determining a calculation result by the signal processor based on the SV signal (aux CT);
- (d) when it is determined from the calculation result by the signal processor based on the SV signal (for aux CT) that an electric line exhibiting the SV signal is in a fault state, determining a fault direction;
- (e) when it is determined from the fault direction determination result that the fault direction is directed to the load-connected electric-line, using a circuit breaker controller to trip a circuit breaker;
- and
- (f) when it is determined from the fault direction determination result that the fault direction is directed to an electric line opposite the load-connected electric-line, determining that a fault does not occur in an area to be protected by the directional over-current ground relay (DOCGR).
Dependencies are inferred from the claim text.