Protective relay system and protective relay device

Patent metadata

Field	Value
Publication number	US-9871365-B2
Application number	US-201314653148-A
Country	US
Kind code	B2
Filing date	Dec 16, 2013
Priority date	Jan 15, 2013
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A protective relay system includes plural protective relay devices protecting a power system based on electrical quantity data from the power system, and a communication between the protective power devices is performed via a network. The protective relay device includes a clock unit periodically clocking a timing at which sampling is performed on an electrical quantity of the power system, a relay computing unit performing a relay computation based on the electrical quantity data having undergone the sampling and electrical quantity data received via the network, a random-number creating unit creating a random number, and a synchronization-frame processing unit setting a timing of sending a synchronization frame to another protective relay device via the network based on the random number created by the random-number creating unit.

First claim

The invention claimed is:

1. A protective relay system comprising a plurality of protective relay devices that protect a power system based on electrical quantity data from the power system, a communication between the protective relay devices being performed via a network,
the protective relay device comprising:
a clock unit periodically clocking a timing at which sampling is performed on an electrical quantity of the power system;
a relay computing unit performing a relay computation based on the electrical quantity data having undergone the sampling in accordance with the timing clocked by the clock unit and electrical quantity data contained in an electrical quantity frame received from another protective relay device via the network;
a random-number creating unit creating a random number; and
a synchronization-frame processing unit setting a timing of sending a synchronization frame to the another protective relay device via the network based on the random number created by the random-number creating unit,
wherein when sequentially obtaining identical random numbers from the random-number creating unit, the synchronization-frame processing unit obtains again a random number, and sets the timing based on the random number obtained again.

2. The protective relay system according to claim 1 , wherein the synchronization-frame processing unit sets the timing of sending the synchronization frame when a predetermined certain period of time is passed from a timing of sending the electrical quantity frame that contains the electrical quantity data having undergone the sampling.

3. The protective relay system according to claim 2 , wherein the synchronization-frame processing unit sets the timing of sending the synchronization frame within a fluctuation allowable time that is set beforehand.

4. The protective relay system according to claim 1 , wherein the synchronization-frame processing unit sets the timing of sending the synchronization frame within a fluctuation allowable time that is set beforehand.

5. A protective relay device comprised in the protective relay system according to claim 1 .

6. The protective relay system according to claim 5 , wherein the synchronization-frame processing unit sets the timing of sending the synchronization frame within a fluctuation allowable time that is set beforehand.

7. The protective relay system according to claim 1 , wherein the synchronization-frame processing unit sets the timing of sending the synchronization frame when a predetermined certain period of time is passed from a timing of sending the electrical quantity frame that contains the electrical quantity data having undergone the sampling.

8. The protective relay system according to claim 1 , wherein the synchronization-frame processing unit sets the timing of sending the synchronization frame within a fluctuation allowable time that is set beforehand.

Assignees

• Toshiba Kk

Inventors

• Kawarada Akira
• Mori Takahiro
• Inukai Michihiko
• Sugiura Hideaki
• Nishida Tomonori

Classifications

• H02H7/261

  involving signal transmission between at least two stations (transmission of signals in general H02H1/0061) · CPC title

• H02H1/0092 Primary

  concerning the data processing means, e.g. expert systems, neural networks · CPC title

• G05B15/02

  electric · CPC title

• H02H3/28

  involving comparison of the voltage or current values at two spaced portions of a single system, e.g. at opposite ends of one line, at input and output of apparatus {(for transformers H02H7/045)} · CPC title

• G06F1/12

  Synchronisation of different clock signals {provided by a plurality of clock generators} · CPC title