JPH04340315A - Protective relay system - Google Patents

Abstract

PURPOSE:To get a protective relay system which can automatically perform the setting and the protective cooperation of a protective relay and can easily confirm the overload property after sling. CONSTITUTION:The settings of protective relays 1, 2, and 3 are decided with each setting switch 4, and these settings are transmitted to a monitor 11 through a transmission circuit 6, and based on these settings, a conversion circuit 8 operates overload property and displays the overload property on the same screen of a display circuit 9.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection relay system that can collectively set the protection coordination of each protection relay.

0002

2. Description of the Related Art Circuit breakers are installed in power receiving and distribution equipment to open and close electrical circuits. Furthermore, in the event that a failure occurs in the electrical circuit, a protective relay is installed so that the circuit breaker is operated to selectively cut off the failed part over a minimum section.

[0003] This protective relay is used by selecting or combining protection elements such as overcurrent, ground fault, and overvoltage depending on the object to be protected. In addition, in the event of a failure, the operating characteristics (overload characteristics) are used to selectively cut off the failed part in the minimum section.
It is necessary to optimally select and coordinate protection in a systematic manner. Therefore, using an overcurrent relay as an example, we will explain how to achieve conventional protection coordination. In general, the operating characteristics of a protective relay are:
It is expressed as an inverse time characteristic on a logarithmic graph with current and time as axes, and the operating characteristics are uniquely determined by setting the operating time and other factors. When protective relays are connected in cascade, the upper and lower protective relays are set so that they operate more quickly as they go lower, thereby minimizing the cut-off period.

In other words, the operating characteristics of the upper protective relay and the operating characteristics of the lower protective relay are superimposed on the same graph so that the operating characteristics of the lower protective relay are below the operating characteristics of the upper protective relay. The setting value is corrected by the setting means to make the optimum setting value. This work is performed manually based on the catalog of the protective relay.

[0005]

[Problems to be Solved by the Invention] In this method of protection coordination, when the number of protective relays increases, setting errors are likely to occur, and as a result, an accident such as damage to the load may occur. Furthermore, there is no easy way to check the operating characteristics of an integer constant, and testing the operating characteristics by actually passing current would require a large current source. SUMMARY OF THE INVENTION An object of the present invention is to provide a protective relay system that automatically performs setting work and allows easy confirmation of operating characteristics or protection coordination. [Structure of the invention]

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention detects the current flowing through a load that has different overload characteristics and is connected to the main circuit bus through a circuit breaker, and detects the current flowing through the load. Multiple protective relays operate circuit breakers according to current values to protect the power system, and settings values for setting the overload characteristics of these protective relays are received via a transmitting circuit, and these settings are It is comprised of a calculation means for calculating each overload characteristic based on the value, and a display means for displaying on one screen the overload characteristics of each of the plurality of protective relays obtained from the calculation means. Further, the calculating means includes a determining means for performing protection coordination by comparing the calculated overload characteristics of each of the protective relays, and a modifying means for modifying the set value according to the result of this determination.

[0007]

[Operation] In such a configuration, the calculating means calculates the overload characteristics of each protective relay based on each setting value received via the transmitting circuit, and the display means displays these overload characteristics on the same screen. Since the overload characteristics can be automatically set, confirmation after setting can be easily performed. In addition, the overload characteristics of each protective relay are compared and determined using arithmetic means, and the setting value is modified according to the results of this determination, making it easy to coordinate the protection of each protective relay. .

[0008]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a protective relay system according to the present invention.

In FIG. 1, 1, 2, and 3 are protective relays (herein referred to as overcurrent relays), 4 is a setting switch, 5 is a circuit breaker, 6 is a transmitting circuit, 7 is a receiving circuit, 8 is a converting circuit,
9 is a display circuit, 10 is a printer, and 11 is a monitor, which is a personal computer in this embodiment. Also,
Protective relays and circuit breakers are connected in cascade. The overload characteristics of the protective relays 1, 2, and 3 are set by a setting switch 4. For example, anti-time, strong anti-time, super anti-time,
Set characteristics such as long reaction time, current setting, time setting, etc. These set values are received by the receiving circuit 7 of the monitor 11 via the transmitting circuit 6 and the communication line. In the monitor 11, a conversion circuit 8 converts the set value received by the receiving circuit 7 into an IT curve (overload characteristics), and a display circuit 9 displays these overload characteristics. As shown in the figure, the higher the overload characteristic of the protective relay 1, the longer it will operate for the same load current value. In addition, the protective relay that displays overload characteristics can be selected on the monitor 11, and if necessary, the protective relay can be selected on the printer 1.
You can also print it out with 0. Further, a configuration diagram of a protective relay system according to another embodiment is shown in FIG. 2.

In FIG. 2, a monitor 11 includes a discriminating circuit 1 that calculates and compares overload characteristics based on the setting values sent from the transmitting circuit 6 of the setting switch 4 of each protective relay.
2, and a correction circuit 13 that outputs a correction signal to the receiving circuit 14 of the setting switch 4 of the protective relay whose setting value needs to be corrected based on the determination result.

The determination circuit 12 transmits the calculated overload characteristics to the display circuit 9, and compares these overload characteristics to determine whether or not there is a relationship between the overload characteristics of the upper and lower protective relays as described above. Determine whether As a result, if the setting value of any one of the protective relays 1, 2, and 3 needs to be corrected, the correction circuit 13 outputs a correction signal to the receiving circuit 14 of the setting switch 4 of the corresponding protection relay. This correction signal is given, for example, the corresponding identification code of the protective relays 1, 2, and 3, and is transmitted to the receiving circuit 14 of the setting switch 4 of the protection relay whose setting value needs to be corrected. It looks like this.

0012

As described above, the present invention detects the current flowing through the load which has different overload characteristics and is connected to the main circuit bus through the circuit breaker, and switches the circuit breaker according to the load current value. A plurality of protective relays operate to protect the power system, and set values for setting the overload characteristics of these protective relays are received via a transmitting circuit, and each overload is detected based on these set values. By comprising a calculation means for calculating load characteristics and a display means for displaying the overload characteristics of multiple protective relays obtained from the calculation means on a single screen, setting work can be performed automatically and confirmation after setting can be performed. can also be easily done. In addition, the calculating means is configured with a determining means for performing protection coordination by comparing the overload characteristics of each protective relay calculated based on the received set value, and a modifying means for modifying the set value according to the result of this determination. , it is possible to easily coordinate the protection of each protective relay.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a protective relay system of the present invention.

FIG. 2 is a configuration diagram of a protective relay system according to another embodiment of the present invention.

[Explanation of symbols]

Claims (2)

[Claims] 1. A current flowing through a load having different overload characteristics and connected to the main circuit bus through a circuit breaker is detected, and the circuit breaker is operated according to the load current value to control the power system. An operation that receives multiple protective relays that provide protection and set values for setting the overload characteristics of these protective relays via a transmission circuit, and calculates the overload characteristics of each of them based on these set values. A protective relay system comprising: means for calculating overload characteristics of each of the plurality of protective relays obtained from the calculating means, and display means for displaying on one screen the overload characteristics of each of the plurality of protective relays obtained from the calculating means. 2. The calculating means includes a determining means for performing protection coordination by comparing the calculated overload characteristics of each of the protective relays, and a modifying means for modifying the set value according to the result of this determination. The protective relay system according to claim 1, characterized in that: