JPS5961423A - Power system protecting controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a power system protection and control device for controlling and inspecting the operation of protective equipment in a power system.

[Technical background of the invention and its problems]

There are various devices that make up power system protection and control devices, but in recent years, advances in static protective relays, general-purpose programmable controllers, and microcomputers have made it possible to realize protection and control devices using these devices. Throughout the world, efforts are being made to improve the reliability of power system equipment and save labor on maintenance.

Such power system protection/control devices are equipped with various inspection functions such as relay operation inspection, circuit breaker operation inspection, and power outage interlock inspection depending on the purpose and function.

For the above inspections, it is necessary to check in advance whether the circuit breakers and other protective devices are operating normally as the power system situation changes, so check commands are output to check the operation of the circuit breakers and other protective devices. This is something to check.

In addition, the above-mentioned power system protection and control device can be used to
Accident systems must be separated from healthy systems. However, during the operation inspection of the protective equipment, an accident was detected because the circuit breaker and other protective equipment were operating according to the inspection command.
It is essential to have a function that cancels the inspection command and returns to the protection/control state, which is usually called an accident response function, so that the inspection of protective equipment such as circuit breakers can be stopped and the protection function against accidents is activated. be.

The accident detection signal that activates the above accident response function is:
The signal must be able to be output instantly even at a lower signal level than the trip signal for tripping the circuit breaker.

However, with conventional power system protection and control devices, when an inrush current flows into a load such as a transformer connected to the main circuit, this inrush current is mistakenly determined to be an overcurrent due to an accident, and the protection equipment is activated. Sometimes inspections were canceled.

The above will be explained in detail below with reference to a conventional power system protection/control device shown in FIG. In FIG. 1, a transformer 3 is connected as a load to a power source 1 via a breaker 2, constituting a main circuit of an electric power system. Further, a current transformer 4 is installed between the line between the breaker 2 and the transformer 3 to detect the current flowing through the main circuit. The output of the current transformer 4 is input to an overcurrent relay 5. This overcurrent relay 5 is
In order to prevent malfunction due to inrush current during excitation of the transformer 3, a tripping command A having a time limit characteristic is transmitted to the breaker 2.
At the same time, an accident response signal B having instantaneous characteristics for transmitting an accident in the main circuit to the outside is input to a programmable fault controller (hereinafter referred to as SQC) 6 built in a central processing unit.

This SQC6 has a control function circuit 6A as an internal function configuration.
and an accident determination section 6B as shown in FIG.

and an inspection function circuit 6B2, and the accident response signal B is input to the inspection function circuit 6B.

Still, the output signal of the operation panel 7 is given as an input to the control function circuit 6A of the SQC 6. The output of this control function circuit 6A is given to the circuit breaker 2 via the control device 8.

In the conventional power system protection/control device configured as described above, assume that the operation panel 7 is operated to output an inspection command to inspect the breaker 2 and power system protection equipment (not shown).・In FIG. 1, when the operator operates the operation panel 7 and inputs an inspection command to the control function circuit section 6A of the SQC 6, the output of the control function circuit 6A sends a closing command to the breaker 2 via the control device 8. , and turn on circuit breaker 2. When the circuit breaker 2 is turned on, a rush current flows through the transformer 3. The current transformer 4 installed in the main circuit due to this rush '1 current detects an overcurrent accident and supplies an accident detection current to the overcurrent relay 5. The overcurrent relay 5 receives the fault detection current and causes the circuit breaker 2 to
and outputs a tripping command signal A for a time-limited operation,
An instantaneous accident response signal B is output to the inspection function circuit 6B of the SQC 6.

In the inspection function circuit 6B that receives the accident response signal B, the accident determination section 6B determines whether or not the accident response signal B is caused by an accident.If it is determined that the accident response signal B is caused by an accident, the accident determination signal C is is input to the inspection cancellation command section 6B2, and an inspection cancellation command signal is output to the control function circuit 6A. The control function circuit 68 that receives the inspection stop command signal stops outputting the check command and stops checking the operation of the protective equipment.

As mentioned above, in the conventional system, the inrush current caused by the closing of the circuit breaker 2 is detected as a fault current, and inspection operations of the protective equipment are stopped even though it is not an accident.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks, and is capable of instantly stopping the inspection operation when an overcurrent accident occurs in the electric power system during the inspection operation of the protection equipment of the electric power system. In addition, even if an overcurrent accident occurs, it is possible to provide a protection/control device for a power system that can continue inspection operations of protective equipment if an erroneous accident detection signal is still output. With the goal.

[Summary of the invention]

The power system protection/control device according to the present invention is applied to a power system in which a protection device is connected between a power source and a load, and when an inrush current flows into the power system,
By detecting the inrush current with an accident detection means such as an overcurrent relay and outputting an operation command signal, the protective equipment described above is activated, and when the protective equipment is inspected, it is possible to prevent the inflow of the inrush current from occurring. The above object is achieved by determining the time until extinction by locking the signal that causes the protective device to perform the inspection operation.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Third
The figure is a circuit configuration diagram showing an embodiment of a power system protection/control device according to the present invention.

In FIG. 3, the same parts as in FIG. 1 and FIGS.

The SQC 9 in this embodiment is composed of a control function circuit 9A and an inspection function circuit 9B. Above inspection function circuit 9
B is an accident response signal B with a low level operation setting and instantaneous operation of the overcurrent relay 5, and a breaker closing command C and control outputted from the operation panel 7 to close the breaker 2. Breaker 2 output from functional circuit 9A
The input signal is a breaker operation inspection command. The inspection function circuit 9B outputs an inspection cancellation command E to the control function circuit 9A as its output signal.

Next, the detailed configuration of the inspection function circuit 9B will be explained with reference to FIG. In the inspection function circuit 9B shown in FIG. 4, a breaker closing command C and a breaker operation inspection command R are inputted to an OR element 9B1, and the output thereof is inputted to a pulse generator 9B2. The OR element 9B2 is connected to the OR element 9B2.
When either the breaker closing command C or the breaker operation check command is input to f31, a pulse signal F which is converted into a pulse signal for a time T (this time T will be explained later) is output. .

In addition, in the above, inputting the breaker closing command C or the breaker operation inspection command to the inspection function circuit 9B means that the breaker 2 is closed via the control function circuit 9A and the control device 8. When it goes down, it becomes the other side.

The main pulse signal F is inverted by the inverter 9B3, and this inverted signal G is inputted to the AND element 9B4 together with the fault response signal B from the overcurrent relay 5. The output of the AND element 9B4 is the accident determination section 9B1 in FIG.
It is configured to be connected to an accident determination section 9B5 and an inspection cancellation command section 9B6, which have the same functions as the inspection cancellation command section 9f32.

Then, the inspection cancellation command unit 9B6 outputs the inspection cancellation command E to the control function circuit 9A.

Note that the time T for converting the output signal from the OR element 9B into a signal in the /E signal converting section 9B2 is
This is the time from the generation to the disappearance of the rush current that occurs when the power is turned on.

Next, the operation of this embodiment configured as described above will be explained. Operate the operation panel 7 in order to check the operation of the power system protection equipment. The operation panel 7 outputs an inspection command to the control function circuit 9A of the SQC 9, and also sends a breaker closing command C to the inspection function circuit 9BK. 'Then, the output signal from the control IM1 function circuit 9A is input to the control device 8, and the breaker 2 is closed by the output signal of the control device M8, and the operation of the breaker 2 is checked. It is assumed that the operation inspection of protective devices other than the breaker 2 and the operation inspection of devices other than the above-mentioned protective devices are continued even after the operation inspection of the breaker 2 is completed.

When the circuit breaker 2 is turned on, a rush current flows through the main circuit to which the transformer 3 is connected as a load.

When this inrush current occurs, a detection current corresponding to the inrush current flows through the current transformer 4 provided in the main circuit. When this detected current satisfies a predetermined value, the overcurrent relay 5 provides a high level operation setting rate and time-limited operation to the breaker 2.
At the same time, an accident response signal B is sent to the inspection function circuit 9B of the SQC 9.

The accident response signal B with the low level operation setting and instantaneous operability inputted to the inspection function circuit 9B of the SQC 9 is inputted to the AND element 9B4 of the inspection function circuit 9B. The OR element 9BH of this inspection function circuit 9B has a control function circuit 9A.
A breaker operation check command is input.

The output signal of the OR element 9B1 is then converted into a pulse generator 9B2.
, and in this pulse generator 9B2, OR element 9B,
A pulse signal F is outputted by pulsing the output signal of the circuit breaker, that is, the breaker operation inspection command, for a time T from the generation of the inrush current to the time of extinguishment. This pulse signal F is applied to the inverter 9B.
3, the signal level is inverted, and an inverted signal (M number G) is output. This inverted signal G is input to the fault response signal B from the overcurrent relay 5 to the AND element 9B4.

At this time, the inverted signal G has a signal level of "0" during the time T.
'', and the accident reaction signal B has a signal level of ``1'' during the same time period, so no signal is output from the AND element 9B4 during the above time T. Therefore, the accident determination section 9BS and the inspection cancellation command section 9B6 do not operate, so the inspection cancellation command E is not output. Therefore, during the above-mentioned time T, the operation check of the protective equipment is continued. In addition, in such a rush current to the transformer 2, the overcurrent relay 5 sends a low-level signal, so the breaker 2 does not trip (2 command A is not output, and the breaker 2 does not trip). Not done.

On the other hand, after the time T has elapsed, the inverted signal G becomes the signal level "1", so when an actual overcurrent accident occurs in the power system, the overcurrent relay 5 is activated and the accident response signal B
When ``)'' is output, the AND element 9B4 outputs a signal to activate the accident detection section 9B5.The accident determination section 9B5 determines whether the output signal from the AND element 9B4 is due to an overcurrent accident. If it is determined that this is due to an overcurrent accident, a signal is output to the inspection stop command section 9B6.The inspection stop command section 9B6 outputs an inspection stop command E to the control function circuit 9A, and stops the operation inspection of the protective equipment. In this case, an actual overcurrent accident occurred in the power system, so
A tripping command A is output from the overcurrent relay 5 to the breaker 2, and the breaker 2 is tripped to perform an accident response function.

As described above, in this embodiment, even if an inrush current due to the closing of the circuit breaker 2 flows into the main circuit when inspecting the operation of the protection equipment of the power system, the operation inspection can be continued without interruption. When an actual overcurrent accident occurs in the power system, the accident response function can be quickly and reliably performed to trip the circuit breaker 2.

The present invention is not limited to the above embodiment, and may be applied to a motor having an inductance in addition to the transformer 3 as a load, and each component is realized by having the same function as the present embodiment. Various modifications may be made without changing the gist of the invention.

〔Effect of the invention〕

According to the present invention described above, when an erroneous fault detection signal is output even though an inrush current flows due to the closing of a breaker and an overcurrent fault has not occurred, Since the output of the fault detection signal is blocked in order to continue checking the power system's protection equipment, the time required for the fault to disappear is determined even when no overcurrent fault has actually occurred in the power system. Regardless, if the inrush current associated with the closing of a circuit breaker is mistakenly detected as an overcurrent accident, it is possible to continue checking the operation of the power system's protective equipment without interruption, and to ensure that there is no actual overcurrent accident in the power system. When an accident occurs, it is possible to provide a power system protection/control device that can quickly and reliably perform an accident response function.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing a conventional power system protection and control device, FIG. 2 is a detailed circuit configuration diagram showing the main parts of FIG. 1, and FIG. 3 is a power system protection and control device according to the present invention. FIG. 4 is a circuit configuration diagram showing one embodiment of the control device. FIG. 4 is a detailed circuit configuration diagram showing the main parts in FIG. 3. 1... Power supply, 2... Breaker, 3... Transformer, 4
...Current transformer, 5...Overcurrent relay, 7...Operation panel, 8P control device, 9...Zorogram multiple sequence controller (SQC), 9A...Control function circuit,
9B...Inspection function circuit, yBl...Or confectionery, 9B
2... Pulse generator, 9B3... Inverter, 9B4
...AND element, 9B5... Accident determination section, 9B6.
...Inspection cancellation command department. Applicant's agent Patent attorney Takehiko Suzue / Figure 3FgJ?

Claims (1)

[Claims] In an electric power system in which a power source and a load are connected via a protective device, an accident detection means outputs an operation command signal to operate the protective device when an overcurrent flows to the load, and the protective device an operation unit that outputs an operation inspection command signal to perform an operation inspection; and when the accident detection means detects an accident, the operation unit is configured not to output the operation inspection signal during the time from the inflow of fault current until its disappearance. 1. A power system protection/control device comprising: an inspection operation control unit for controlling the power system;