JP3232806B2 - Protection relay system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective relay system and, more particularly, to a protective relay system suitable for obtaining reliable protection coordination between upper and lower relays.

[0002]

2. Description of the Related Art A conventional protection relay having an operation characteristic for obtaining protection coordination is described in Japanese Patent Application Laid-Open No. 61-132031.

[0003]

In the above prior art, since the operating characteristics of the relays are fixed, if the operating characteristics of the upper and lower relays have already been determined, there is no flexibility in selecting the operating characteristics of the relays. Did not always get protection coordination.

[0004] Further, in selecting the operation characteristics, there is a problem that the selection width is narrowed because the selection must be made in consideration of an error.

It is an object of the present invention to obtain reliable protection coordination by freely setting the operating characteristics of the lower relay.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a current detecting means for detecting a current in an electric circuit and an accident detecting at least one of overload, short circuit and ground fault based on the output of the current detecting means. A protection relay system including a detection unit and a signal generation unit that generates a signal for generating an alarm or disconnecting an electric circuit when an abnormality occurs based on an output of the accident detection unit. A transmission request unit to be transmitted and a protection relay having a characteristic setting unit for setting its own operation characteristic based on the transmitted operation characteristic data of another relay are provided as a higher-order relay, and a transmission request of operation characteristic data from another relay is provided. Receiving transmission request receiving means;
A protection relay having characteristic transmission means for transmitting its own operation characteristic data based on the transmission request is provided as a lower relay, and the upper relay is self-controlled so that protection coordination can be achieved by the transmitted operation characteristic data of the lower relay. Upper or lower protection by either setting the operation characteristics of the lower relay or comparing the transmitted operation characteristic data of the lower relay with its own operation characteristics and modifying the lower relay so that protection coordination can be achieved. The upper relay has a control means using a microcomputer, and the operation characteristics are stored in a ROM or a RAM connected to the control means, and a display for displaying the operation progress or the operation characteristics is provided. This is achieved by configuring the means.

[0007]

The lower relay transmits its operating characteristics to the upper relay, and the upper relay receives this, compares its own operating characteristics, and checks whether protection coordination is possible or not. If not, it changes its own operating characteristics and stores the data in the storage element, or sends an output to change the lower operating characteristics data and changes the lower relay operating characteristics data.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In this embodiment, a current detecting means for detecting a current in an electric circuit and an overload based on an output of the current detecting means are provided.
Protection comprising: an accident detecting means for detecting at least one of a short circuit and a ground fault; and a signal generating means for generating a signal for generating an alarm or disconnecting an electric circuit when an abnormality is detected based on the output of the accident detecting means. Using a protection relay having a transmission requesting means for transmitting operation characteristic data from another relay and a characteristic setting means for setting its own operation characteristic by the transmitted operation characteristic data of the other relay, as a higher-order relay A current detecting means for detecting a current in the electric circuit, an overload, a short circuit, and an accident detecting means for detecting at least one of a ground fault based on an output of the current detecting means; and A protective relay provided with signal generating means for generating a signal for generating an alarm or disconnecting an electric circuit in the event of an abnormality, and transmitting a request for transmission of operating characteristic data from another relay. And it takes the transmission request receiving means, in which the protective relay having a characteristic transmission means for transmitting its own motion characteristic data used as the lower relay, to constitute a protective relay system based on the transmission request.

FIG. 1 is a diagram showing connections of upper and lower relays of a protection relay system according to one embodiment of the present invention. Explaining the system configuration of the present embodiment, an electric circuit 101 as an electric system has an upper relay 1 at the highest level, an upper relay 2 at the next level, and a branch relay 3 as a lower relay at the lower level.
4, 5 are connected. Each of the upper and lower relays includes a circuit for transmitting and receiving operation characteristic data, and the relays are connected by data transmission and reception lines 6, 7, 8, and 9. The upper relay has a storage element for storing characteristic data,
It has a lower characteristic data comparison operation function. Further, each relay has a function of displaying the operation progress.

An electrical system fault includes an overload, a short circuit, and a ground fault. In the relay according to the present embodiment, the fault detecting means detects a fault in the electrical system based on the current in the circuit. To generate a signal for disconnection. Also,
In this embodiment, the upper and lower relays are combined as a system, and the upper relay in the system causes the lower relay to transmit operation characteristic data to obtain upper and lower protection coordination.

The higher-order relay sets its own operation characteristic so that protection coordination can be achieved by the transmitted lower-layer relay operation characteristic data, or compares the transmitted lower-layer relay operation characteristic data with its own operation characteristic, Upper or lower protection coordination is obtained by either modifying the lower relay characteristics so that protection coordination can be achieved. The higher-order relay has control means using a microcomputer or the like to perform such control, and the operating characteristics are determined by a ROM (Read Only Memory) or a RAM connected to the control means.
(Randam Access Memory). Further, a display means may be provided to display the operation progress or the operation characteristics.

The operation of this system will be described. The upper relay 2 issues a transmission request for operating characteristic data to the lower relays 3, 4, and 5. In response, the operating characteristic data of the lower relays 3, 4, and 5 is transmitted to the upper relay 2 via the connection lines 7, 8, and 9, respectively. Next, the high-order relay 2 compares its own operation characteristic data with the transmission data from the low-order relay by using the high-order and low-order characteristic data comparison operation function, and determines whether protection coordination is possible or not. In the case of no, the relay 2 transmits the operation characteristic data for protection coordination to the lower branch relays 3, 4, and 5 via the connection lines 7, 8, and 9, and stores the data in the lower relay composed of RAM. The element is stored and operated according to the transmitted operating characteristic data.

Next, the uppermost relay 1 transmits the operation characteristic data of the relay 2 in the same manner as described above, and determines the protection coordination between the two. Send to Next, it is determined again whether or not protection coordination with the relay 2 and the branch relays 3, 4, and 5 is possible in the same order as described above. In the determination of protection coordination between the relays 1 and 2, the operation characteristic data is transmitted from the relay 1 to the relay 2 and the relay 2 determines. If the operation characteristic data is not transmitted from the relay 2 to the relay 1, The protection coordination determination of the relays 2, 3, 4, and 5 again becomes unnecessary.

FIG. 2 shows an example of the configuration of a relay for detecting an overcurrent as an electric circuit fault. The configuration and operation are as follows. The current of the electric circuit 101 is detected by a current transformer 10 as a current detecting means.
And supplies it as a current signal to a peak hold circuit 12 which is an analog signal generating means. The peak hold circuit 12 generates an analog signal related to the supplied current signal, and converts this signal into a timed current setting circuit 22 as first reference value setting means and an instantaneous level detection circuit 28 as second level detection means. And supply them respectively. The output of the time-limit current setting circuit 22 is supplied to a time-limit level detection circuit 24 and a time limit means 14, which are first level detection means. The time limit means 14 generates a signal having a period inversely proportional to the square of the magnitude of the current in the electric circuit 1 and generates the signal. The count means 16 generates this signal when the reset signal from the time limit level detection circuit 24 is output. To be counted.

In this embodiment, the time limit means and the counting means are a central processing unit (CPU) using a microcomputer.
It consists of. The operation progress display means 15 starts operation by a signal from the time limit level detection circuit 24 and
The progress is displayed according to the progress of counting of 1.
When the count value reaches a certain value, the CPU 31 supplies an output signal to the output circuit 20 as output means. The CPU 31 has R
The OM 32 and the RAM 33 are connected, and an initial set value of the time limit characteristic as an operation characteristic is stored in the ROM 32. If the characteristic is changed by the upper relay, the characteristic is R
Stored in AM33. The CPU 31 is connected to an I / O circuit 34 for transmitting and receiving operating characteristic data to and from the upper and lower relays.

The output circuit 20 energizes the relay 18, which is a circuit protection means, based on the output signal. The electric circuit 101
Is larger than the set value of the instantaneous current setting circuit 26, which is the second reference value setting means, the instantaneous level detection circuit 28 supplies an output signal to the output circuit 20 and the relay 1
Energize 8. The relay 18 opens a circuit by energizing a magnetic trip device 18a of an electronic circuit breaker (not shown) connected to a higher order.

The power supply circuit 13 is connected to the electric circuit 1 via the current transformer 11.
01, and supplies the power as a power supply voltage to each unit.

[0019]

According to the present invention, the operating characteristics of the upper and lower relays can be freely changed, so that reliable protection coordination can be obtained.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing a connection between upper and lower relays of a protection relay system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration in a case where the relay in one embodiment of the present invention is an overcurrent relay.

[Explanation of symbols]

1,2,3,4,5 ... Protective relay, 6,7,8,9 ... Data transmission / reception connection line

Claims (1)

(57) [Claims] A current detecting means for detecting a current in an electric circuit;
Based on the output of the current detection means,
Accident detection means for detecting at least one of them;
When an error occurs based on the output of the
Signal generating means for generating a signal for road separation
A protective relay system,Request for transmission that causes other relays to transmit operating characteristic data
Stage and the other relay's operating characteristic data transmitted.
Protection relay having characteristic setting means for setting its own operation characteristics
Equipment as the upper relay, Transmission that receives a request for transmission of operating characteristic data from another relay
Communication request receiving means and its own operation characteristics based on the transmission request.
Protection relay having characteristic transmitting means for transmitting the characteristic data
Prepared as a lower relay, The upper relay is an operating characteristic of the transmitted lower relay.
Operating characteristics so that protection coordination can be achieved with reliability data
Or send the operation characteristics of the lower relay
Comparing protection data with self-operating characteristics to achieve protection coordination
Modify either the lower relay as described above
, Protection coordination at the lower level, The upper relay is a control means using a microcomputer.
Having a stage, wherein the operating characteristic is a RO connected to the control means.
Stored in M or RAM to display operation progress or operation characteristics
Protection relay system characterized by comprising display means for performing
Tem .