JPH07322469A - Grounding protective relay - Google Patents

Abstract

PURPOSE:To execute the inspection including the confirmation of property relevant to high frequency ingredients by performing the inspection of operation by the simulated zero-phase current and simulated zero-phase voltage including the ingredients of higher harmonics where grounding fault is simulated. CONSTITUTION:A microprocessor 5 judges YES, and performs test waves generation processing. In the test wave processing, this judges whether the test is resistance grounding test or not, and if it is the resistance grounding test, this outputs a digital signal equivalent to the simulated zero-phase voltage E02 and simulated zero-phase current 102 for resistance grounding. This digital signal is converted into the simulated zero-phase voltage E02 and the simulated zero-phase current 102 of analog signals with a D/A converter 7. At the time of inspection, a changeover switch 8 is in close condition, a simulated zero-phase current 102 and a simulated zero-phase voltage E02 are inputted into a zero- phase current filter 1 and a zero-phase voltage filter 2. The microprocessor 5 performs fault judgment, and checks whether an auxiliary relay 6 has operated correctly or not. Hereby, the inspection including the confirmation of the property relevant to harmonics can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground fault protection relay having a self-check function.

[0002]

2. Description of the Related Art There is a ground fault protection relay that constantly monitors the system state in an electric power system and, if a ground fault occurs, immediately detects it and disconnects the fault section. FIG. 7 is a block diagram of a conventional ground fault protection relay. Reference numeral 21 is a zero-phase current filter for extracting a fundamental wave from the input zero-phase current I01, 2
Reference numeral 2 denotes a zero-phase voltage filter that extracts a fundamental wave from the input zero-phase voltage E01, and 23 denotes A / A that converts the outputs of the zero-phase current filter 21 and the zero-phase voltage filter 22 into a digital signal.
The D converter, 24 is a rectangular wave generator that converts the outputs thereof into pulse signals for phase angle determination.

Further, 25 is a microprocessor which detects a ground fault based on a digital signal and a pulse signal and operates an auxiliary relay 26 for protecting the ground fault, and 27 is a sine wave from a voltage input inputted from a terminal 30. A voltage input filter to be generated, 28 is a changeover switch, and 29 is a relay output contact. FIG. 7 shows the structure of a ground fault direction relay, which is one type of ground fault protection relay, and when the ground fault direction relay has a constant relationship between the zero phase voltage, the magnitude of the zero phase current, and the phase difference. It works.

Next, the operation of such a ground fault protection relay will be described. The changeover switch 28 in the normal state is in an open state, and the zero-phase current I01 and the zero-phase voltage E01 are input to the zero-phase current filter 21 and the zero-phase voltage filter 22 from sensors (not shown) provided in the power system, respectively. It Further, the changeover switch 28 at the time of inspection is closed, and the test waveform from the voltage input filter 27 is input. The zero-phase current filter 21 and the zero-phase voltage filter 22 convert the input signal into the fundamental wave, that is, the commercial frequency (50 Hz or 60 Hz).
Extract only.

The A / D converter 23 converts the outputs of the zero-phase current filter 21 and the zero-phase voltage filter 22 into digital signals, and the rectangular wave generator 24 converts them into pulse signals. Then, the microprocessor 25 uses the A / D
The level is determined by the digital signal from the converter 23, the phase angle is determined by the pulse signal from the rectangular wave generator 24, and if both reach the operating range, it is determined that there is a ground fault and the auxiliary relay 26 is activated. And relay output contact 2
Turn on 9.

As described above, in the normal state, the ground fault is determined based on the zero-phase current I01 and the zero-phase voltage E01, and at the time of inspection, the same determination is performed based on the output of the voltage input filter 27 to perform the operation inspection. . Further, the example of FIG. 7 is a ground fault protection relay having a self-inspection function, but as another example, JP-A-56
There is a device described in JP-A-133930, in which a test device is provided outside the protective relay and the test device outputs data simulating an arbitrary waveform to the protective relay at the time of inspection.

[0007]

The conventional ground fault protection relays have been inspected as described above, but in any of the protection relays, a simple sine wave having a constant level is added to the test waveform at the time of inspection. Since it is used, the situation is quite different from the input of zero-phase current and zero-phase voltage when a ground fault actually occurs, and the characteristics of the elements that compose the zero-phase current filter, zero-phase voltage filter, and rectangular wave generator. There was a problem that inspections in the original sense, including confirmation of changes, were not possible. An object of the present invention is to provide a ground fault protection relay capable of confirming characteristics related to harmonic components in order to solve the above problems.

[0008]

According to the present invention, a simulated zero-phase current and a simulated zero-phase voltage containing a harmonic component simulating a ground fault are internally generated at the time of inspection and used as a test input. Is operated to inspect the operation. Further, a filter for extracting the fundamental wave from the zero-phase current and zero-phase voltage, an A / D converter for converting the output of this filter into a digital signal, and the output of the filter for converting into a pulse signal for phase angle determination. A square wave generator,
A microprocessor that detects a ground fault based on a digital signal and a pulse signal, activates a relay, and outputs a digital signal corresponding to a simulated zero-phase current and a simulated zero-phase voltage that simulates the ground fault at the time of inspection. A D / A converter for converting a digital signal from the microprocessor into a simulated zero-phase current and a simulated zero-phase voltage and outputting it to a filter.

Further, a filter for extracting the fundamental wave from the zero-phase current, an A / D converter for converting the output of this filter into a digital signal, a ground fault detected based on the digital signal, and a relay activated. , A microprocessor that outputs a digital signal corresponding to a simulated zero-phase current simulating a ground fault at the time of inspection, and a D / A converter that converts the digital signal from this microprocessor into a simulated zero-phase current and outputs it to a filter It is equipped with and. Further, a filter for extracting the fundamental wave from the zero-phase voltage, an A / D converter for converting the output of this filter into a digital signal, a ground fault detected based on the digital signal, and a relay actuated. A microprocessor that outputs a digital signal corresponding to a simulated zero-phase voltage that simulates a failure at the time of inspection, and a digital signal from this microprocessor that is converted into a simulated zero-phase voltage and that is output to a filter D
/ A converter.

Further, instead of the microprocessor, the microprocessor for detecting the ground fault based on the digital signal and the pulse signal or the digital signal and activating the relay, and the D / A converter are used to detect the ground fault. The simulated zero-phase current and the simulated zero-phase voltage are stored in advance and are output to the filter at the time of inspection. Also, instead of the microprocessor, a first microprocessor that detects a ground fault based on a digital signal and a pulse signal or a digital signal and activates a relay, and a simulated zero-phase current and a simulated zero that simulate the ground fault. The second microprocessor for outputting a digital signal corresponding to the phase voltage to the D / A converter at the time of inspection and confirming whether or not the relay operates.

[0011]

According to the present invention, the operation inspection is performed by the simulated zero-phase current and the simulated zero-phase voltage including the harmonic component simulating the ground fault. Further, at the time of inspection, the microprocessor outputs a digital signal corresponding to the simulated zero-phase current and the simulated zero-phase voltage, and the D / A converter converts this digital signal and outputs it to the filter, so that the operation is checked. . Further, at the time of inspection, the microprocessor outputs a digital signal corresponding to the simulated zero-phase current, and the D / A converter converts this digital signal and outputs it to the filter.
Operation check is performed.

Further, at the time of inspection, the microprocessor outputs a digital signal corresponding to the simulated zero-phase voltage, and the D / A converter converts this digital signal and outputs it to the filter, whereby the operation inspection is performed. Further, the operation inspection is performed by outputting the simulated zero-phase current and the simulated zero-phase voltage stored in the storage device in advance at the time of inspection to the filter. Further, at the time of inspection, the second microprocessor outputs digital signals corresponding to the simulated zero-phase current and simulated zero-phase voltage to D /
Output to the A converter and check if the relay is activated.

[0013]

【Example】

Example 1. FIG. 1 is a block diagram of a ground fault protection relay showing an embodiment of the present invention, FIG. 2 is a timing chart diagram for explaining the operation of a rectangular wave generator of this ground fault protection relay, and FIG. It is a flowchart figure for demonstrating operation. In FIG. 1, 1 is a zero-phase current filter, 2 is a zero-phase voltage filter, 3 is an A / D converter,
Reference numeral 4 designates the outputs of the zero-phase current filter 1 and the zero-phase voltage filter 2 as the zero-phase current pulse signal PI0 and the zero-phase voltage pulse signal PE0.
It is a rectangular wave generator that converts to.

Reference numeral 5 is a microprocessor,
Based on the digital signal from the D / D converter 3 and the zero-phase current pulse signal PI0 and the zero-phase voltage pulse signal PE0, it is determined whether or not there is a ground fault, and when it is determined that there is a ground fault, the auxiliary relay 6 is activated, and during inspection, the ground fault A digital signal corresponding to the simulated zero-phase current I02 and the simulated zero-phase voltage E02 simulating the fault is output. Reference numeral 7 is a D / A converter for converting a digital signal from the microprocessor 5 into a simulated zero-phase current I02 and a simulated zero-phase voltage E02, 8 is a changeover switch, and 9 is a relay output contact.

The present embodiment is an example of a ground fault protection relay that operates as a ground fault direction relay. Next, the operation of such a ground fault protection relay will be described first in normal operation.
The change-over switch 8 is controlled by the microprocessor 5, and the change-over switch 8 in the normal state is open. Therefore, in the zero-phase current filter 1 and the zero-phase voltage filter 2, the zero-phase current I01,
The zero-phase voltage E01 is input.

The zero-phase current filter 1 extracts only the fundamental wave from the input zero-phase current I01 and amplifies it to an appropriate level, and the zero-phase voltage filter 2 similarly extracts the fundamental wave from the input zero-phase voltage E01. Extract only the waves and amplify to a suitable level. The A / D converter 3 converts the outputs of the zero-phase current filter 1 and the zero-phase voltage filter 2 into digital signals, and the rectangular wave generator 4 converts these outputs into the zero-phase current pulse signal PI0 and the zero-phase voltage, respectively. Convert to pulse signal PE0.

In the rectangular wave generator 4, an input as shown in FIG. 2A (here, only the sine wave output from the zero-phase voltage filter 2 is shown) is compared with the reference potential Vref. A comparator (not shown) is provided for the zero-phase current filter 1 and the zero-phase voltage filter 2, and the comparator outputs the outputs of the zero-phase voltage filter 2 and the zero-phase current filter 1 as shown in FIG.
As shown in (b) and (c), the zero-phase voltage pulse signal PE0,
It is converted into a zero-phase current pulse signal PI0.

Then, since the microprocessor 5 is in the normal time at present, the microprocessor 5 returns No in step 101 of FIG.
Therefore, the failure determination process is performed (step 108). In the failure determination process, the levels of the zero-phase current and the zero-phase voltage are determined by the digital signal from the A / D converter 3, and the zero-phase voltage pulse signal PE0 from the rectangular wave generator 4 is determined.
Also, the phase angle is determined by the zero-phase current pulse signal PIO, and if both reach the operating range, it is determined that a ground fault has occurred and the auxiliary relay 6 is activated after a predetermined time.

The determination of the above phase angle is made by detecting the time difference t between the rising times of the zero-phase voltage pulse signal PE0 shown in FIG. 2 (b) and the zero-phase current pulse signal PI0 shown in FIG. 2 (c). Done. The case of FIG. 2 shows the case where the phase angle is 90 °, and the time difference t for determining that the phase angle is 90 ° is 5 ms when the commercial frequency is 50 Hz and 60 Hz, respectively.
ec is 4.17 msec.

In this way, the relay output contact 9 is turned on, and the circuit breaker (not shown) installed in the system is controlled to disconnect the faulty section. After controlling the auxiliary relay 6, the microprocessor 5 monitors the relay output contact 9 to check whether the auxiliary relay 6 has operated correctly (step 109).

Next, the operation at the time of inspection will be described. First, the microprocessor 5 determines Yes in step 101 of FIG. 3, and performs test waveform generation processing. In the test waveform generation process, it is first determined whether or not it is a resistance ground fault test (step 102). In the resistance ground fault test, digital signals corresponding to the simulated zero phase voltage E02 and the simulated zero phase current I02 for the resistance ground fault are generated. Output (step 103).

The simulated zero-phase voltage E02 and simulated zero-phase current I02 simulating a resistance ground fault have waveforms as shown in FIGS. 4A and 4B, and are stored in a storage area (not shown) of the microprocessor 5. Means that digital signals corresponding to these are stored. The digital signal output from the microprocessor 5 is converted by the D / A converter 7 into a simulated zero-phase voltage E02 and a simulated zero-phase current I02 which are analog signals.

At the time of inspection, the changeover switch 8 is in the closed state,
The simulated zero-phase voltage E02 and the simulated zero-phase current I02 are input to the zero-phase current filter 1 and the zero-phase voltage filter 2. Then, the microprocessor 5 performs the failure determination processing (step 108) and the operation confirmation (step 109) as in the above.
In this way, the resistance ground fault test is performed.

If the cable ground fault test is performed, the microprocessor 5 returns Yes in step 104 of FIG.
Then, a digital signal corresponding to the cable ground fault is output (step 105). The simulated zero-phase voltage E02 and simulated zero-phase current I02 simulating a cable ground fault are shown in FIG.
The waveform is as shown in (d), and the inspection similar to the above is performed by these signals.

If the gap ground fault test is performed, the microprocessor 5 returns Yes in step 106 of FIG.
Then, a digital signal corresponding to the gap ground fault is output (step 107). The simulated zero-phase voltage E02 and the simulated zero-phase current I02 simulating the gap ground fault are shown in FIG.
The waveform is as shown in (f), and the inspection similar to the above is performed by these signals.

As described above, the self-inspection of this ground fault protection relay can be carried out, and in particular, different harmonic components corresponding to various ground fault forms such as resistance ground fault, cable ground fault, and gap ground fault. By inputting a test waveform having a zero phase current filter 1, a zero phase voltage filter 2,
It is possible to perform an inspection including confirmation of characteristic changes due to aging of the elements forming the rectangular wave generator 4.

The simulated zero-phase voltage E02 and the simulated zero-phase current I02 shown in FIG. 4 are the complete ground fault described in JEM (Japan Electrical Manufacturers' Association Standard) 1394 which is a standard relating to the ground fault direction relay. It is obtained from the waveforms generated in the system when various ground fault tests such as resistance ground fault, cable ground fault, and gap ground fault are performed. Moreover, since there is no difference in the waveforms generated in the system, the complete ground fault is included in the resistance ground fault.

Example 2. FIG. 5 is a block diagram of a ground fault protection relay showing another embodiment of the present invention, and the same parts as those in FIG. 1 are designated by the same reference numerals. Reference numeral 10 is a storage device for storing the simulated zero-phase voltage E02 and the simulated zero-phase current I02 shown in FIG. 4, which is composed of, for example, a magnetic tape device, a CD-ROM, or a memory.

This ground fault protection relay is also an example of a ground fault direction relay, and the microprocessor 5a performs substantially the same operation as the microprocessor 5 in the example of FIG. The difference is that in the test waveform generation process at the time of inspection, only the storage device 10 is controlled and the test waveform is not directly generated.

That is, the storage device 10 stores the simulated zero-phase voltage E02 and the simulated zero-phase current I02 shown in FIG. 4, and under the control of the microprocessor 5a, the resistance ground fault, the cable ground fault, and the gap ground fault. The simulated zero-phase voltage E02 and the simulated zero-phase current I02 are output according to each test of the fault. As a result, the same inspection as in the example of FIG. 1 can be performed without increasing the load such as the storage capacity of the microprocessor 5a.

Example 3. FIG. 6 is a block diagram of a ground fault protection relay showing another embodiment of the present invention, and the same parts as those in FIG. 1 are designated by the same reference numerals. Reference numeral 5b is a first microprocessor for performing the failure determination processing (step 108 in FIG. 3) of the processing of the microprocessor 5 in FIG. 1, 11 is test waveform generation processing (steps 102 to 107), and operation confirmation (step 109). The second microprocessor.

Although this ground fault protection relay is also an example of a ground fault direction relay, the microprocessor 5b performs a failure determination process, that is, a ground fault failure determination and control of the auxiliary relay 6. Then, the microprocessor 11 performs a test waveform generation process for outputting a digital signal corresponding to the simulated zero-phase voltage E02 and the simulated zero-phase current I02 and confirms the operation of the auxiliary relay 6. As a result, the same inspection as in the example of FIG. 1 can be performed without increasing the load on the microprocessor 5b, and the second microprocessor 11, which is a separate device from the microprocessor 5b, confirms the operation of the auxiliary relay 6. A more reliable inspection can be performed.

Example 4. Although the example of the ground fault direction relay has been described in the above embodiments, the present invention can be applied to a ground fault overcurrent relay. Since the ground fault overcurrent relay operates when the zero-phase current exceeds a certain value, the configuration is the one in which the zero-phase voltage filter 2 and the rectangular wave generator 4 are removed from the example of FIG.

Therefore, the microprocessor is A /
Based on the digital signal of the zero-phase current output from the D converter, it is determined whether or not there is a ground fault, and at the time of inspection,
A digital signal corresponding to the simulated zero-phase current I02 shown in (b), (d) and (f) is output to the D / A converter. Other operations are the same as in the example of FIG.

Example 5. The present invention can also be applied to a ground fault overvoltage relay. Since the ground fault overvoltage relay operates when the zero-phase voltage exceeds a certain value, its configuration is the one in which the zero-phase current filter 1 and the rectangular wave generator 4 are removed from the example of FIG. The microprocessor determines whether or not there is a ground fault based on the digital signal of the zero-phase voltage output from the A / D converter, and at the time of inspection, simulates shown in FIGS. 4 (a), 4 (c) and 4 (e). It outputs a digital signal corresponding to the zero-phase voltage E02.

Example 6. In addition, as another embodiment,
The example of FIG. 5 (Example 2) and FIG. 6 (Example 3) can be applied to each of the above Examples 4 and 5.

[0037]

According to the present invention, since the operation inspection is performed by the simulated zero-phase current and the simulated zero-phase voltage including the harmonic component simulating the ground fault, the inspection including the confirmation of the characteristics related to the harmonic component. Can be carried out and the self-inspection function can be enhanced. Also, by providing a filter, A / D converter, rectangular wave generator, microprocessor, and D / A converter, it operates as a ground fault direction relay and can perform inspections including confirmation of characteristics related to harmonic components. The ground fault protection relay can be realized with a simple configuration.

Further, by providing a filter, an A / D converter, a microprocessor and a D / A converter, the ground fault operates as a ground fault overcurrent relay and can perform inspection including confirmation of characteristics related to harmonic components. The protective relay can be realized with a simple structure. By providing a filter, A / D converter, microprocessor, and D / A converter, a ground fault protection relay that operates as a ground fault overvoltage relay and can perform inspections including confirmation of characteristics related to harmonic components is provided. It can be realized with a simple configuration.

In addition, the storage device simulates a zero phase current during inspection,
Since the simulated zero-phase voltage is output to the filter, inspection including confirmation of characteristics related to harmonic components can be performed without increasing the load such as the storage capacity of the microprocessor.
The second microprocessor outputs digital signals corresponding to simulated zero-phase current and simulated zero-phase voltage during inspection,
Since it is confirmed whether or not the relay is activated, it is possible to perform the inspection including the confirmation of the characteristics related to the harmonic component without increasing the load of the first microprocessor, which is a separate device from the first microprocessor. A more reliable inspection can be performed by the second microprocessor confirming the operation of the relay.

[Brief description of drawings]

FIG. 1 is a block diagram of a ground fault protection relay showing an embodiment of the present invention.

FIG. 2 is a timing chart diagram for explaining the operation of the rectangular wave generator of FIG.

FIG. 3 is a flow chart diagram for explaining the operation of the microprocessor of FIG.

FIG. 4 is a diagram showing waveforms of simulated zero-phase voltage and simulated zero-phase current.

FIG. 5 is a block diagram of a ground fault protection relay showing another embodiment of the present invention.

FIG. 6 is a block diagram of a ground fault protection relay showing another embodiment of the present invention.

FIG. 7 is a block diagram of a conventional ground fault protection relay.

[Explanation of symbols]

1 Zero-phase current filter, 2 Zero-phase voltage filter, 3 A
/ D converter, 4 square wave generator, 5, 5a, 5b microprocessor, 6 auxiliary relay, 7 D / A converter,
10 storage device, 11 second microprocessor.

Claims (6)

[Claims] 1. A ground fault protection relay that activates a relay for ground fault protection by detecting a ground fault based on a zero phase current and a zero phase voltage from a power system, and a harmonic component simulating a ground fault. A ground fault protection relay characterized in that a simulated zero-phase current and simulated zero-phase voltage are generated internally during inspection and used as a test input, and a relay is operated by this test input to perform operation inspection. 2. A ground fault protection relay operating as a ground fault direction relay that detects a ground fault based on a zero phase current and a zero phase voltage from a power system and operates a relay for ground fault protection. A filter that extracts the fundamental wave from the zero-phase current and zero-phase voltage, and an A / D that converts the output of this filter into a digital signal.
A converter, a rectangular wave generator that converts the output of the filter into a pulse signal for determining a phase angle, and a relay that determines whether a ground fault has occurred based on the digital signal and the pulse signal and determines that a ground fault has occurred. , A microprocessor that outputs a digital signal corresponding to the simulated zero-phase current and simulated zero-phase voltage including harmonic components that simulates a ground fault, and a digital signal output from this microprocessor. A ground fault protection relay, which is internally provided with a D / A converter that converts a zero-phase current and a simulated zero-phase voltage and outputs the same to the filter. 3. A ground fault protection relay that operates as a ground fault overcurrent relay that detects a ground fault based on a zero phase current from a power system and operates a relay for ground fault protection. A filter that extracts the fundamental wave from the A / D that converts the output of this filter into a digital signal
A converter and a digital signal corresponding to a simulated zero-phase current that includes a harmonic component simulating a ground fault and determines whether or not a ground fault has occurred based on the digital signal and determines that there is a ground fault. For outputting at the time of inspection, and D / for converting the digital signal output from this microprocessor into a simulated zero-phase current and outputting it to the filter.
A ground fault protection relay having an A converter inside. 4. A ground fault protection relay that operates as a ground fault overvoltage relay that detects a ground fault and operates a relay for ground fault protection based on a zero phase voltage from a power system. A filter that extracts the fundamental wave from the A / D that converts the output of this filter into a digital signal
A converter and a digital signal corresponding to a simulated zero-phase voltage that includes a harmonic component simulating a ground fault and determines whether or not a ground fault has occurred based on the digital signal and determines that the fault is a ground fault. And a D / which outputs a digital signal output from the microprocessor to a simulated zero-phase voltage and outputs the simulated zero-phase voltage to the filter.
A ground fault protection relay having an A converter inside. 5. The ground fault protection relay according to claim 2, 3 or 4, wherein instead of the microprocessor, a ground fault is determined based on a digital signal and a pulse signal or a digital signal. Instead of the microprocessor which operates the relay when it is judged as a failure and the D / A converter, a simulated zero-phase current and a simulated zero-phase voltage including a harmonic component simulating a ground fault are stored in advance and stored in a filter at the time of inspection. A ground fault protection relay, which is internally provided with an output storage device. 6. The ground fault protection relay according to claim 2, 3 or 4, wherein instead of the microprocessor, a ground fault is determined based on a digital signal and a pulse signal or a digital signal. When a failure is determined, the first microprocessor that activates the relay and the digital signal corresponding to the simulated zero-phase current and the simulated zero-phase voltage including the harmonic component simulating the ground fault are D / A during inspection.
A ground fault protection relay, which is internally provided with a second microprocessor which outputs to a converter and confirms whether or not the relay is activated.