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Improved power-line protection

A technology of power line and electric power, applied in the direction of emergency protection device for automatic disconnection, protection for undervoltage or no voltage response, emergency protection circuit device, etc.

Inactive Publication Date: 2003-11-19
AREVA T&D
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It should therefore be realized that while it is easy to choose a slower operating time to ensure that correct identification is achieved when relays with predetermined time delays are used, such use must be limited to grids with relatively few series connection breaks.

Method used

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Embodiment Construction

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] exist figure 1 And in Figure 2, the arrows near relays R1, R21, etc. are used to indicate the direction of the fault the relay will respond to. OC means figure 1 The relays R1, R21, R22, R31, etc. in the Figure 2a , 2b The overcurrent protection function of R31 in the Figure 2a , 2b Accelerated overcurrent protection function of relays R1, R21 and R22 in Figure 2a relays R1', R21', R22' and Figure 2b Undercurrent and undervoltage protection functions of relays R21, R22 and R31 in the ; tf1, tf2, tf3 and tf4 are figure 1 , 2a and 2b the setting value of the forward action time of the OC and AOC relays in different positions; tr1 and tr2 are Figure 2a UCV relays R1’, R21’, R22’ and Figure 2b The setting value of the reverse action time of the relays R21, R22 and R31 in .

[0020] It should also be noted that in Figure 2a and 2b , the various relays shown are associated with their respective cir...

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Abstract

A protection system for an electrical power line system of the type comprising radially connected power line sections, wherein a first electrically upstream one of the line sections is connectable to a power source. The protection system comprises at least one relay installed at or near at least the upstream end of each line section to protect that line section, each relay having an associated circuit breaker. The relays are provided with a first set of accelerated overcurrent functions and a second set of under-current / under-voltage functions, the relays being directional and the first and second sets of functions being time graded in reverse to each other. The first and second sets of functions are distributed amongst the relays such that if an under-current / under-voltage function in a second relay located downstream of a first relay triggers operation of a circuit breaker associated with the second relay, an accelerated overcurrent function in the first relay triggers accelerated operation of a circuit breaker associated with the first relay, thereby to isolate from the power source the line section that the first relay protects.

Description

Field of Invention [0001] The present invention relates to the protection of power lines, and in particular to an improved method of protecting so-called "radially connected" power line systems. Background technique [0002] One of the most important power line (including power cable) fault protection techniques known is the so-called overcurrent (OC) protection technique. See, eg, "Protective Relays Application Guide", GEC Alsthom Protection and Control Ltd., Third Edition, June 1987. A protection device using this technology monitors the current in the power line through a connection to a current transformer in the line, and when the current exceeds a predetermined threshold, the protection device issues a trip signal to open the power line circuit breaker associated with the device. Such protective devices are traditionally called "relays" and have current and time settings that are adjustable to be stepped relative to the settings of adjacent relays to allow correct ide...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/06H02H3/24H02H7/30
CPCH02H3/24H02H3/063H02H7/30
Inventor 薄志谦
Owner AREVA T&D