JPH04172911A - Protective relay - Google Patents

Abstract

PURPOSE:To prevent the malfunction and wrong non-operation of a protective relay by detecting and deciding the status of a CPU for settling and, when the CPU is not sound, changing the settling value to a prescribed value by means of a relay CPU and fail-safe relay CPU. CONSTITUTION:A main detection relay CPU 4 and fail-safe relay CPU 5 detect and discriminate the status of a settling CPU 2 by using a watch dog timer 7 and, since the CPU 2 is not sound when a watch dog timer defective signal (i) is '1', no malfunction nor wrong non-operation takes place even when the CPU 2 is not sound and wrong data are sent by storing a prescribed value in a settling value buffer. When the signal (i) is normal, relay decision is performed by using settling value converting data (c) sent from the CPU 2.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a protective relay for protecting an electric power system, and particularly to a protective relay that includes a main relay and a fail-safe relay and shares the aforementioned setting section. .

(Prior art) A protective relay device that protects an electric power system works to minimize the impact of an accident by issuing a command to immediately disconnect the faulty part when a fault occurs in the equipment to be protected. If the device malfunctions, there is a risk that the protected equipment may be destroyed or the power supply may be interrupted. Therefore, it is extremely important to prevent erroneous operation of the protective relay device.

The following methods are generally adopted as measures to prevent this.

This is a method in which a main relay and a fail-safe relay are used in combination, and the final output is obtained by logical product of the two relay outputs. While a main relay detects an accident within the section to be protected, a fail-safe relay detects the presence or absence of an accident by a simpler operation judgment than the main relay, and if one relay malfunctions, it may malfunction. This is prevented.

FIG. 4 is a side view of the configuration of a conventional protective relay in which the above-mentioned main relay and fail-safe relay share a setting section.

In FIG. 4, the system electricity amount a is subjected to analog/digital conversion processing by the analog input section 3, and is then input to the main relay CPU 4. Passed to failsafe relay CPU 5.

Further, the setting processing CPU 2 performs input processing of the setting value data b from the setting panel 1, and the input setting value data is sent to the main relay CPt14 after a predetermined conversion process.
．． Passed to fail-safe relay CPIJ 5. The main relay CPU 4 and fail-safe relay CPυ5 send out a relay output e and a fail-safe relay output f after relay determination such as failure section detection.

These relay outputs e and f are input to the NO circuit 6.

This 8N[1 circuit 6 outputs a trip command g when both the main relay output e and the fail-safe relay output are "1".

Next, the response of the apparatus shown in FIG. 4 constructed as described above will be described.

First, assuming that the device is in a healthy state, when an accident occurs, both the main relay 4 and the fail-safe relay 5 will send out operating outputs, so the relay output e and the relay output f will be "1", and the ^ND circuit The output g of 6 becomes "1" and the trip command g is output.

Next, when main relay CPt14 is not in a healthy state, it performs an incorrect operation when no accident has occurred, and the main relay output e becomes “
1 “No matter what happens, the fail-safe relay output f is “
0", and the output of the AND time F!+6 becomes "0" and the trip command is locked.

(The section to be solved by the invention) However, if the setting processing CPU 2 is not in a healthy state and performs an incorrect operation, the setting conversion data C changes to incorrect data, and the main relay CPjl 4 and fail-safe relay Passed to CPυ5. Main relay CPt14.

Since the fail-safe relay CPt15 makes a relay determination based on erroneous setting value data C, it may malfunction or malfunction in the event of an accident even when the power system is healthy.

The present invention has been made to solve the above-mentioned problems, and even if the CPU for settling processing is no longer in a healthy state, relay judgment is performed based on incorrect data sent from the CPU for settling processing. Relay CP to avoid
It is an object of the present invention to provide a protective relay capable of preventing malfunction or malfunction of a fail-safe relay CPυ.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, a protective relay according to the present invention provides a protection relay that protects the CPU from setting when the CPU for setting is not in a healthy state due to a hardware failure or the like. A configuration comprising means for detecting and determining whether or not the CPU is in a healthy state, and means for changing the setting value to a predetermined value when the setting processing CPU is not in a healthy state. And so.

(Function) In the above configuration, it is detected and determined whether or not the setting processing CPU is in a healthy state due to a hardware defect, etc., and when the setting processing CPU is not in a healthy state, the relay CPU and fail-safe relay cPu are set to the set value. is changed to a predetermined value, so even if cPυ for settling processing is no longer in a healthy state due to hardware failure and sends incorrect data,
Since the relay is determined based on the predetermined value, it is possible to prevent malfunctions and malfunctions.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of an embodiment of a protective relay according to the present invention. In this embodiment, a power system is used that is equipped with a function to prevent malfunction or malfunction of relay judgment when the CPU for setting processing is not healthy. FIG. 2 is a block diagram showing the configuration of a protective relay.

In FIG. 1, the same parts as in FIG. 4 are given the same reference numerals, and their explanation will be omitted.

This embodiment has a configuration in which a watchdog timer circuit 7, which is hardware for detecting and determining whether or not the settling processing CPU 2 is in a healthy state, is added to the conventional power system protective relay shown in FIG. It has become.

Then, the reset signal outputted from the settling processing CPυ2 is input to the watchdog timer 7, and from the watchdog timer 7, the watchdog timer failure detection signal i is sent to the main detection relay CPU4 and the failsafe relay CPU5. The configuration includes additional input hardware.

Next, the effect will be explained.

In the program processing of the settling processing CPU 2, "O" is outputted to the watchdog timer 7 in response to a reset signal for a predetermined period at a predetermined period. The watchdog timer 7
The timer is reset when the reset signal i is "0", and the watchdog timer failure detection signal i is outputted as "0". If the reset signal remains at "1'° for a predetermined period of time or more, it is assumed that the settling processing CPU 2 is defective, and "1" is output as the watchdog timer defect detection signal.

The operation of the above configuration will be described below with reference to the flowchart of FIG.

The main detection relay CP is activated by the watchdog timer 7.
U4. Fail safe relay CPU 5 is C for setting process
Step 2: Detect whether Pυ2 is healthy or not.
1) If the watchdog timer failure signal i is "1", the setting processing CPt12 is not healthy, so by storing a predetermined value in the setting value buffer (step 2
3) Even if the CPU 2 for setting processing is not healthy and sends out erroneous data, relay determination is carried out using a predetermined value (step 24), so there will be no malfunction or malfunction. If the watchdog timer failure signal is normal, a relay determination is made based on the setting value conversion data C sent from the setting processing CPU 2 (step 2).
2゜Step 24).

As explained above, according to an embodiment according to the present invention,
Detection 8 determines whether or not it is in a healthy state, and sets the CP for settling processing.
When U is not in a healthy state, the relay CPU and failsafe relay CPU change their setting values to predetermined values, so it is possible to prevent the setting CPU from being in a healthy state due to a hardware failure and sending out incorrect data. Also, since the relay is determined based on the predetermined value, it is possible to prevent malfunctions and malfunctions.

FIG. 3 shows a relay CPU according to another embodiment of the present invention.

This is a flowchart of fail-safe relay.

In the above embodiment, when the watchdog timer failure detection signal is not normal, a predetermined value is stored in the set value buffer, whereas in this embodiment, when the watchdog timer failure detection signal is not normal, the predetermined value is stored in the set value buffer. Since the y-fa storage operation is not performed, relay judgment can be made using the setting value when the settling processing CPU is healthy, and relay judgment malfunctions when the settling processing CPU is not healthy.

Malfunctions can be prevented.

Note that the present invention is not limited to the above-described embodiments; for example, as a means for detecting whether or not the settling CPU is healthy, the settling CPU increases the contents of a predetermined memory at regular intervals, and The relay and fail-safe relay determine whether or not the predetermined memory has been increased correctly, and if the predetermined memory has been increased correctly, the setting processing CP
U is healthy, and if the predetermined memory does not increase, it can be determined that the settling processing CPU is not healthy. Furthermore, the setting processing CPU and the main relay CPU may be shared, and configured as one CPU.

[Effects of the Invention] As explained above, according to the present invention, the CPU for setting processing
is in a healthy state due to a hardware failure, etc., and when the setting processing CPU is not in a healthy state, the relay CPU and fail-safe relay CPU change the setting value to a predetermined value. Even if the CPU for setting processing is not in a healthy state due to a hardware failure or the like and sends incorrect data, it will malfunction because relay judgment will be made based on the predetermined value.

A protective relay for a power system that can prevent malfunctions can be provided.

[Brief explanation of the drawing]

Figure 1 is based on the present invention! A configuration diagram of one embodiment of the II relay, FIG. 2 is a flow chart showing the processing contents of the configuration shown in FIG. 1, FIG. 3 is a flow chart of another embodiment of the present invention, and FIG. 4 is a conventional power It is a block diagram showing the composition of the protection relay of the system. 1... Setting panel 2... CPU for setting processing
3...Analog input section 4...Main relay CPU5
...Fail-safe relay CPU 6...AND circuit 7 Watchdog timer Patent applicant Toshiba Corporation Patent attorney Ishii Fuo Figure 1'''1゛ Figure 2 Go to next process Figure 3 Figure 4

Claims (1)

[Claims] In a protective relay that has a setting section that inputs a setting value through an external setting operation and sends setting data to the main relay and fail-safe relay, when the setting section is defective, the fault is detected and the main relay and fail-safe relay are activated. means for transmitting a failure signal to the main relay and fail-safe relay; means for detecting a failure in the setting section using the failure signal in the main relay and the fail-safe relay; and means for treating the setting data as a predetermined value when the failure is detected. protective relay.