JPH0145804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for inspecting a protective relay, and more particularly to a method for inspecting a protective relay that can also grasp characteristics.

The electric power system is a gigantic system in which power generation, transmission, transformation, distribution, and other facilities are interconnected by disconnectors and switches, and is installed over a wide area, and when an abnormality occurs, the impact on society can be extremely large. big. For this reason, it is necessary to promptly eliminate abnormalities such as power system accidents in the smallest section to ensure the health of other power systems. A protective relay device is installed to fulfill this mission. This protective relay device is naturally considered to be highly reliable, and various measures have been taken to prevent it from malfunctioning (malfunction, malfunction), but it is difficult to reduce the probability of malfunction. has its limits. For example, what is the malfunction rate and malfunction rate?
This may be due to reasons such as the fact that improving one requires sacrificing the other, making it extremely difficult to improve both at the same time, or it requires a large amount of cost to even slightly reduce the rate of malfunction. .

For this reason, while the protective relay device itself is constructed and manufactured in such a way that malfunctions are as difficult to occur as possible, the health of the protective relays that make up the protective relay device in operation must be checked from time to time. Let's do it. Part 1
One method is constant monitoring, which detects abnormalities on the malfunction side by detecting that the protective relay is operating even though the conditions under which it should not be operating are not present. Furthermore, in the automatic inspection method, abnormalities on the side of malfunction or non-operation are mainly detected by applying an appropriate inspection input to the protective relay instead of the input from the power system and checking its response. According to these methods, abnormal operation of the protective relay can be detected. Then, regular inspections are carried out by maintenance personnel once every few years. In this case, characteristics management (static characteristics, dynamic characteristics, etc.) of the protective relay, which cannot be accomplished by the above-mentioned automatic inspection, is also performed, and deterioration due to aging is also detected.
By organically implementing the various measures described above, it is possible to reduce the probability of malfunction of the protective relay device.

By the way, among these, periodic inspections place a large burden on maintenance personnel. For example, if we look at a single disconnector, 40
~50 protective relays are required, and during periodic inspections, each of them and the combined protective relay group are managed from various viewpoints. Therefore, it requires a large amount of man-hours from maintenance personnel to conduct periodic inspections of protective relays throughout the power system. Moreover, since maintenance personnel must be sufficiently skilled, it is becoming difficult to carry out periodic inspections as the power system expands.

In view of the above, it is an object of the present invention to provide a method for inspecting a protective relay that can automatically and easily realize the characteristics of the protective relay that were previously performed by maintenance personnel during periodic inspections.

In the present invention, an inspection input that continuously changes the magnitude and phase is applied to a two-input protective relay. This method draws an impedance locus parallel to the basic axis of the input impedance plane, and its characteristics are determined according to the time it takes for the protective relay to change its operating state after the signal is applied.

Although the present invention is applicable to any type of two-input protective relay, the following description will primarily be directed to a mho characteristic distance relay.

FIG. 1 shows a so-called impedance plane in which resistance R and reactance X are orthogonal coordinates, and the protection area of a mho characteristic protection relay is expressed as MHO.

FIG. 2 is a diagram showing the connection relationship between the inspection device 450 and the protective relay device RY1 for realizing the inspection method of the present invention. The protective relay device RY1 includes various protective relays, TI _A , TI _B , and TI _C are current input terminals of A, B, and C phases, respectively, TV _A , TV _B ,
TV _C is a voltage input terminal for A, B, and C phases, respectively.
In the example in the figure, signals are applied to terminals TI _C and TV _C ,
In this case, it is assumed that an input is applied to the C-phase Moh characteristic distance relay, and its operating state is given to the output terminal ROUT16. The inspection device 450 provides inspection signals to terminals 1 and 2, and input terminals 46-16.
The output of the C-phase distance relay is obtained. Although the inspection device shown in FIG. 2 can be implemented as an analog or digital device, an example in which it is implemented as a digital device will be described in detail with reference to FIG. 3.

In the figure, the arithmetic processing section 4 includes a central processing unit (CPU) 41, as is well known.
Read-only memory (ROM) that stores calculation programs and basic data for sine wave generation
43, random access memory (RAM) 44 used for memory of various data, timing circuit 42 that provides a reference time interval, input/output control circuit 45
It is comprised of an address counter 40 that records addresses for reading basic data for sine wave generation, and a storage circuit 47 for storing various setting values used in calculations.
The signal generator 5 generates a digital value which is the output of 45.
Latch circuits 51 and 5 that temporarily store D _1(t) and D _2(t)
2, a data selector 53, a D/A converter 54 for converting digital values into analog quantities, a sample holder 55 for temporarily holding analog quantities,
56, 57, 58, and low-pass filters 59, 60 for attenuating high-order harmonics. Further, 6 is a protective relay characteristic printing and recording section, which is composed of a printing and recording circuit 61 and a printing control circuit 62. 7 is a protective relay characteristic display section,
It consists of a viewing control circuit 72 for display such as a CRT.

First, basic data for sine wave generation stored in the read-only memory ROM will be explained.
This stores each instantaneous value, for example, for one cycle when a sine wave is sampled at predetermined time intervals. To be more specific, the fifth
For example, when the sine wave in figure a is sampled at intervals of φ = 30 (degrees), 12 values (A,
B, C, . . . J, K, L) are stored in the ROM shown in FIG. 4 in order. and,
Assign an address m = 1 to the ROM location that stores data A, an address m = 2 to data B, and then assign an address (m = 12 in this case) to the final data L in the same manner. It is attached. These data can be accessed by specifying address m.
Although data at any position can be retrieved arbitrarily, in the case of the present invention described below, the data are read in the order of the addresses, and when m=12 is reached, the data is returned to m=1 and read out again. In the case of the present invention, the read cycle is constant, so when the series of signals read from the ROM as described above is converted into an analog quantity, this is equivalent to obtaining a sine signal as shown in Figure 5a. .

In the present invention, a signal whose magnitude and phase difference change continuously is used as the inspection input. Such a signal can be easily obtained by using the basic data for sine wave generation stored in the ROM.
An example of the method of generating an inspection signal according to the present invention will be described below with reference to FIGS. 7 and 8. First, in Fig. 7, 1 is the first time-series signal generation section, and its output v ₁ is expressed as v ₁ =V _A sinωt...(1) 2 is the second time-series signal generation section. That output
v ₂ ′, v ₂ ′=V _B sin(ωt+θ) …(2) where t; time V _A , V _B ; maximum value θ; leading angle of the second time series signal with respect to the first time series signal ω: shall be expressed in terms of angular velocity.

In the gain control circuit shown by 3 in Fig. 7, the above
As a time series signal v ₃ corresponding to v ₂ ′, v ₃ = t _o ′ / Tv ₂ ′ = t _o ′ / TV _B sin (ωt + θ) ... (3) where T is the time required for the change in magnitude and phase is a constant that determines , and is an integer multiple of the minimum time interval of the time series signal.

t _o ′; 0, 1, 2...T is given. This gives v ₂ ' a variable gain over time. The output signal v ₄ that is finally determined as the sum of v ₁ and v ₃ is expressed as v ₄ =V _A sinωt+t _o '/TV _B sin(ωt+θ) (4).

Now, if we represent each of the above signals on a vector diagram, it will be represented as shown in Figure 8, and v ₁ and
There is a phase difference of θ between it and v ₂ ′. V ₃ obtained by gain controlling V ₂ ' over time is on v ₂ ' as a vector, and moves from the origin O to point B over time. In this case, if we use a variable gain that sequentially gives a signal with a size that divides the OB into four, then when t _o ′=0, v ₃ =0, and when t _o ′=1, v ₃ (t _o ′= 1), when t _o ′=2, v ₃ (t _o ′=2), when t _o ′=3, v ₃ (t _o ′=3), when t _o ′=4, v ₃ (t _o ′) =4)=v ₂ '. Then, the sum v ₄ of v ₃ and v ₁ at each point in time is v ₄ (t _o ′=0)=v ₁ when t _o ′=0, and v ₄ ( _{t o} ′= 1), when t _o ′=2, v ₄ (t _o ′=2), when t _o ′=3, v ₄ (t _o ′=3), when t _o ′=4, v ₄ (t _o ′) =4).

Here, if we pay attention to the temporal change of _V4 , its vector locus moves from point C to point D, and a time-series signal is obtained in which both the magnitude and phase change. The above is the basic explanation of the present invention, and in short, a signal whose absolute value changes over time.
This can be achieved by simply finding the sum of v ₃ and the normal sine signal v ₁ . The only thing to keep in mind here is to have an appropriate phase difference θ between v ₁ and v ₃ , and v ₁ ,
The magnitude of v ₂ ′ may be arbitrarily selected, and the frequencies of v ₁ and v ₂ ′ may be the same. This means that only one power supply is required as the source of v ₁ and v ₃ , and a delay element to provide the phase difference θ and a variable gain control circuit to provide variable gain are required. By simply providing this, it is possible to create a signal whose magnitude and phase change together. Note that here, the fact that the phase changes over time means that the frequency changes.

The signal generation method described in FIGS. 7 and 8 is similar to that described above.
This can be easily done based on the basic data for sine wave generation stored in the ROM. That is, as explained above, the data read out from the ROM in FIG. 4 in a predetermined order is v ₁ and v ₂ ' in FIG.
However, for v ₁ and v ₂ ′, the phase difference θ is obtained by using different addresses to read at the same time. The only thing left to do is to multiply and add different gains for each control period.
v ₄ is obtained. Programmatically, the signal can be made into a signal whose magnitude and phase difference are continuously variable as described above.

In the present invention, the variable signal is used, for example, as the voltage input v of a motor distance relay, and thus requires another current input i. This current input is a normal sine wave signal. still,
In the present invention, the voltage and current inputs are as described above, but since impedance is determined by the relative relationship between the two inputs, it is sufficient to use current and voltage signals that can draw a trajectory parallel to the fundamental axis of the impedance plane. . Here, since it is easier to consider impedance fluctuations when the current input is fixed, it is simply determined as above. Although it is already well known, the correspondence relationship between where a certain current and voltage input is located on the impedance plane will be explained here. If v and i are in phase, they exist on the horizontal axis OR in FIG. If the phase is reversed, it will be on the line connecting the origin O and the negative resistance (-R). If v is π/2 (rad) ahead of i in phase, it will be on the vertical axis OX, and v will be on a line connecting the negative reactance (-X) to the origin O, where v is π/2 (rad) behind i in phase. If the current vector is projected onto the impedance plane, it will be in the OR direction. Therefore, the direction of the impedance locus on the impedance plane is determined depending on the direction of the current input in FIG. 8. Incidentally, if the vector of i is in phase with v ₂ ' in FIG. 8, then means the positive resistance axis on the impedance plane. In this case, the locus drawn on the impedance plane in relation to the voltage input v moving from point C to point D becomes C'-D' in FIG. 1, and this locus is parallel to the OR axis. In addition, in Figure 8,
If the magnitude of v ₁ is variable and it is set to v ₁ ′, the trajectory will be C″−D″. This is a translation of C'-D'.

As described above, by applying an inspection input that changes in magnitude and phase, an impedance locus that crosses the protected area on the impedance plane can be obtained. In this case, the starting point C' and ending point D' of the trajectory and the time required for movement are all known, and are determined by the type of current and voltage input. In response to the input of such an impedance locus, the protective relay changes its state from "non-operating", "operating", and "non-operating". In the present invention, the characteristics of the protective relay are known according to the time until this state change. .

Figure 6 shows a program for implementing the inspection method of the present invention, which is based on the ROM shown in Figure 3.
It is stored in 43. To explain this outline first, ST-03 is the initial value setting. ST-
311 performs management to execute programs starting from ST-312 at a predetermined period Δt. ST-
The current signal i at that point in time is determined and output by the processing from 312 to ST-316. In ST-321 to ST-325, the voltage signal v at that time is determined and output. In other words, ST
-312 to ST-325 determine the instantaneous value of the inspection signal. ST-331 to ST-335 input and record the operating status of the protective relay at each instant. ST-
341 and ST-342 are the above ST-312 to ST-335
By repeatedly executing the process for a fixed time T at every predetermined period Δt, the generation of the inspection sine wave signal and the response of the protective relay at that time are recorded. ST
-343 and ST-344, the conditions of the inspection sine wave signal are changed to repeatedly perform signal generation and response monitoring. ST-350 performs editing output display of response results.

The details of this program shown in FIG. 6 will be explained below. When this program starts, first in step ST-03, the set value given to the set value storage circuit 47 in FIG. 3 is checked and input. Here, a case will be described in which an inspection input representing the straight line trajectory C'-D' shown in FIG. 1 is applied.
The setting values in this case will be clarified in the following explanation.

First, in step ST-311, the following processing is started only when there is a flag signal periodically given by the timing circuit 42 of FIG. Flag signal period Δt
is a time corresponding to the reciprocal of the product of the frequency of the alternating current signal generated for inspection and the number of basic data for generating the sine wave signal shown in FIG. ST-312 creates a digital signal D1 _(t) regarding the current at this point. Specifically, the counter 4 in FIG. 3 stores the address m for reading the basic data shown in FIG.
Counter 40I for current information among 0
Specify the address mi registered in , obtain basic data, and multiply this by the setting value KI to obtain D _1(t) . K.I.
is obtained from the set value storage circuit 47. In the ST-313, this digital signal D1 _(t) is applied to the signal generating section 5 in FIG. 3, and the signal generating section is controlled to provide an analog current signal i~ from the terminal 1. This specific process will be explained in detail in ST-322. In ST-314, the contents of address counter 40I in Figure 3 above mi
It is checked whether the value has reached 12, that is, whether the final value L of the ROM in FIG. 4 has been reached. When mi=12, mi=1 in ST-315, and when mi≠12, ST-
At 316, the contents of the address counter 40I are updated so that mi=mi+1.

The above processing from ST-312 to ST-316 is as described above.
It is repeated at a period Δt determined by the flag signal of ST-311, and the content mi of the address counter 40I is updated each time.As a result, the analog signal obtained from terminal O1 is a sine signal as shown in Figure 5a. Become.

The processing from ST-321 to ST-325 is for creating the variable voltage signal. ST-321
Now we obtain a digital signal D _2(t) corresponding to the instantaneous value of the variable voltage signal. Specifically, as shown in the details in Figure 9, first, in ST-3210, 2 in Figure 8 is used.
The digital data D _v1 and D _v2 that are the basis of the two sine signals v ₁ and v ₂ ' are read out. This is an address counter 40V prepared for voltage signals (see Figure 3)
_The addresses mv ₁ and v ₂ ′ registered in
Read by specifying mv ₂ ′. In ST-3211, D _(v1) is multiplied by a constant K, and this is set as D _(v1) . With this operation, the vector locus in Figure 1 can be changed to C′−D′ or C″−
It is determined whether the
D _(v2) is multiplied by the coefficient t _o '/T. In ST-3216, D _2(t) is obtained by adding D _(v1) and t _o ′/TD _(v2 ′ ₎ . The above is the processing of ST-321, and as will be described later, this processing is repeated at intervals of Δt, and each time the address mv ₁ ,
mv ₂ ′ is updated, converted into an analog quantity, and output. How the signals of each part become during this processing will be explained with reference to FIG. (a) is
t _o ′/TD _(v2 ′ ₎ , (b) represents D _2(t) , and (c) represents D _(v1) .
first.

Before time t ₀ , it is the starting point mode, and since t _o ′ = 0 in ST-3213, t _o ′/TD _(v2 ′ ₎ = 0, and therefore D _2(t) = D _(v1). An analog voltage signal corresponding to the value is output. In this case, v ₁ in FIG. 8 is obtained as the voltage input, and the impedance corresponding to C' in FIG. 1 is obtained due to the balance with the current input i.
Also, from time t ₂₄ onwards, the end point mode of ST-3215 is selected and t _o ′=T, so t _o ′/T D _(v2 ′ ₎ = D _(v2 ′ ₎ and D _{2( t)} = D _(v1) + D _(v2 ′ ₎ .
In analog terms, this is equivalent to combining v ₁ and v ₂ ' in FIG. 8, so v ₄ is obtained as a voltage output, and the impedance in this case is point D'.
Then, from t ₀ to t ₂₄ , ST-3214 generates a signal _{t o} ′/TD _(v2 ′
₎ is obtained. This signal is as shown in Figure 10a,
This is a signal whose magnitude (maximum value) is continuously variable while the phase remains constant. When this is added to the signal D _(v1) of constant period and constant magnitude shown in c of the same figure, a signal whose phase and magnitude continuously change is obtained as shown in b of the same figure. In D _2(t) in Figure b, the fact that the phase is changing means that at each time point t ₀ , t ₆ , t ₁₂ , t ₁₈ , t ₂₄
This is clear when compared with the size of D _(v1) . Although the change in size is not necessarily clear in the diagram,
As is clear from the vectors in FIG. 8, it changes continuously. Therefore, it takes time T to obtain an impedance trajectory moving from C' to D'. ST-322 performs conversion of D2 _(t) into an analog quantity and output operation. ST-323 checks whether the address mv ₁ = 12, mv ₂ ' = 12, and if "yes", ST-324 sets mv ₁ = 1,
Set mv ₂ ′ = 1, and if “no”, mv ₁ = mv ₁ in ST-325
+1, the contents of the address counter 40V are updated so that mv ₂ ′=mv ₂ ′+1.

Here, as described above, the processing in ST-313 and ST-322 will be explained with reference to FIG.
In the signal generating section 5 of FIG. 3, digital signals D _1(t) and D _2(t) to be output are latched by latch circuits 51 and 52, respectively. Next, the data selector 53 selects one of the data D _{1 (t)} and D _{2 (t)} based on the data select signal S ₁ , and D _{1 (t)} and D _{2 (t)} are sequentially sent to the D/A converter 54. is converted into an analog quantity given by Next, the D/A converted analog quantities are temporarily held in sample holders 55 and 56 by sample hold signals SH ₁ and SH ₂ .
At this time, the time relationship between the data select signal S ₁ and the sample hold signals SH ₁ and SH ₂ is that after S ₁ selects the latch circuit 51, SH ₁ is output, and after selecting the latch circuit 52, SH ₂ is output. A signal is given synchronously as output.
In this case, the output of 51 becomes 55, and the output of 52 becomes 5.
Moved to 6. Then sample hold signal SH ₃
Accordingly, the outputs of sample holds 55 and 56 are collectively held in sample holds 57 and 58. This is for the purpose of ensuring output simultaneity between the two analog signals. Since the above is repeated at each time interval of the timing circuit 42 described above, the outputs of the sample holders 57 and 58 become stepwise signals. In order to remove this, low-pass filters 59 and 60 are connected, and analog AC signals i and v corresponding to digital quantities are obtained at output terminals O ₁ and O ₂ . Note that although the signal generating section 5 is necessary for outputting in analog form, it can also be output in digital form as well. Moreover, this value can be arbitrarily used directly in other programs of the computer without outputting it as a digital value.

While applying the inspection input as described above,
In ST-331, the operating state of the protective relay is input at each point in time in the change mode, and in ST-332, the _state is determined. The content is set to "1", and if the memory is inactive, the memory R _ij is set to "0". In ST-335, _i of addresses i and j of memory Rij is updated to i=i+1. However, in the initial state, i=0 and j=0. ST-
In step 341, it is checked whether the time T _D after applying the signal whose magnitude and phase change has passed T, and if it has passed, the process moves to ST-343. If not, T _D = T _D +1 in ST-342
Then, return to ST-311 and repeat the same process. This T is the time required for the change mode, and when this time elapses, ST-3212 selects the end point mode.

By repeating the process until reaching time T, C'-
The processing for D′ is completed, and in ST-343 it is determined whether K multiplied by D _(v1) in ST-3221 of FIG. 9 has reached the limit value K ₀ , and if not, ST −344
In addition to changing K, the address i of the memory R _ij is set to 0, and j is set to j+1. In other words, by changing K through this process and repeatedly running the program shown in Figure 6, an input that results in an impedance locus like C''-D'' in Figure 1 will be applied, and the response at that time will be recorded in memory. become. Here K
may be set in any way, but for example, in the example of FIG. 1, it is preferable to set it to a value that scans the entire area of the MHO characteristic.

Looking at the recorded contents of the memory R _ij when the above series of programs were executed, this is the 11th
It can be expressed as shown in the figure. Same figure,,
indicates the contents recorded in the memory R _ij during the change mode period T when the constants K are K ₁ , K ₂ , K ₃ (K ₁ >K ₂ >K ₃ ). In this figure, the horizontal axis is time, and the first
In accordance with Figure 0, the time T is from t ₀ to t ₂₄ . As mentioned above, the address i of the memory R _ij is i = i + 1 at each time in the period T, and i = 0 at t ₀ , so this horizontal axis can be considered to be the size of the address i. good. By the way memory R _ij
Regarding the address j, this is because j=j+1 is set each time the constant K is changed, so this is the
Corresponds to the magnitude of v ₁ in the figure. Here K=
When K ₁ , j=1, when K=K ₂ , j=2, K=K ₃
Suppose that j=3 when . Since the impedance locus is parallel to the horizontal axis as shown in FIG. 1, the magnitude of K (value of j) represents the distance in the vertical axis direction, but originally it is information representing the starting point C'. and
By predetermining the spectral direction of v ₁ , v ₂ ', or i, the direction of the impedance locus is determined. Therefore, by referring to i and j and displaying the stored contents of the memory _Rij , information about the mho characteristic MHO can be obtained. Here, since the address i means time, the present invention can be described very simply as follows.
It can be said that this method applies an input that draws an impedance locus parallel to the fundamental axis of the impedance plane, and then monitors the time until the protective relay changes in response.

Figure 12 is a copy of the recorded contents of the memory R _ij in Figure 11, taking into account the direction of the vector v ₁ , and this shows the protected area of the protective relay.
You can learn about MHO. Here, when displaying the stored contents of FIG. 11 on the impedance plane of FIG. 12, it is necessary to consider the operation and recovery time of the protective relay. In other words, in Figure 11,
If K = K ₁ , it becomes operational for the first time when i = 6, but this is the operational state when i = 3, for example, and this only appeared when i = 6. . Although this is not taken into consideration in FIG. 12, the display can be made more accurate if the operating time is also considered. The protective relay characteristic print recording section 6 or the protective relay characteristic display section 7 displays or prints information regarding the characteristics according to each address ij of the memory R _ij and its contents. A detailed explanation of these display or printing controls will be omitted, but since the operating state of the protective relay is recorded in a time-corresponding manner, those skilled in the art can easily carry out the explanation.

Although the above description has been made using a distance interrupter with a Moh characteristic as an example, this can be similarly applied to a single or multiple two-input protective relay having a protection area on an impedance plane.

According to the present invention, which has been described in detail above, it is possible to automatically grasp the characteristics of a protective relay, which was conventionally done by maintenance personnel during periodic inspections. This not only significantly reduces the burden on maintenance personnel, but also
It is possible to uniformly improve inspection accuracy. In particular, in the present invention, the impedance trajectory is moved parallel to the fundamental axis of the impedance plane and stored sequentially, which is convenient for displaying on a cathode ray tube using a CRT or the like. In other words, when an impedance locus is drawn parallel to the resistance axis, it can be displayed immediately by reading out the recorded content along the moving direction of the scanning line of the cathode ray tube, and when an impedance locus is drawn parallel to the reactance axis, the stored content can be displayed immediately. can be displayed relatively easily by controlling the reading order.

Note that various ways can be considered as implementation forms of the inspection method of the present invention. For example, in the case of digital protective relay devices, which are expected to increase in number in the near future, the computer itself can incorporate the program shown in FIG. In this case, it can be said that most of the conventional periodic inspections by maintenance personnel are not necessary. Of course, it can also be a separate device that can be easily added. The device shown in FIG. 3 can also be configured and used as an inspection tool for maintenance personnel, in which case wiring, etc. will be the main task of the maintenance personnel. When using such an inspection tool, the device can be simplified by only generating inspection input and recording the response of the protective relay, and processing such as editing and displaying recorded information is performed by a separate device. be able to. As described above, whichever measure is adopted, it can be said that the present invention plays an extremely important role in improving the reliability of the protective relay device.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the protection area of the Moh characteristic distance relay on an impedance plane, Fig. 2 is a diagram showing the connection relationship between the inspection device of the present invention and the protective relay device,
Figure 3 is a diagram showing the hardware configuration of a digital computer when the present invention is implemented, and Figure 4 is a ROM.
FIG. 5 is a diagram showing the concept for obtaining the basic data of FIG. 4, and FIG. 6 is a program representing an embodiment of the inspection method of the present invention. 7 is a schematic configuration diagram showing an example of the inspection signal generation method of the present invention, and FIG.
The figure is a vector diagram for each part signal in Figure 7, Figure 9 is a detailed explanatory diagram of a part of the program in Figure 6,
Figure 0 is a diagram showing the values of each part as analog values when signals are generated digitally according to Figure 9.
FIG. 1 is a diagram showing the recorded contents of the memory R _ij according to the present invention, and FIG. 12 is a diagram showing the relationship between the recorded contents of FIG. 11 and the protected area. 450...Inspection device, RY1...Protective relay device, 4...Arithmetic processing unit, 41...CPU, 43...
...ROM, 44...RAM, 40...address counter, 45...input/output control circuit, 5...signal generator, 54...D/A, 59, 60...filter.

Claims (1)

[Claims] 1. A method for detecting the characteristics of a protective relay on an impedance plane by applying a variable current and voltage signal as an inspection signal to a two-input protective relay having a protection area on an impedance plane. In a method for inspecting a protective relay, a current and voltage signal such that the impedance locus shifts in a direction parallel to the basic axis on the impedance plane is applied to the protective relay as the inspection signal, and when the inspection signal is being applied, an appropriate The operating and non-operating status of the protective relay is stored in cycles, and the operating and non-operating status is memorized by sequentially applying inspection signals with different impedance trajectories parallel to the basic axis. A method for inspecting a protective relay, characterized by detecting characteristics of the protective relay on an impedance plane according to stored information of operation. 2. In a protective relay inspection device for detecting the characteristics of a protective relay on an impedance plane by applying a variable current and voltage signal as an inspection signal to a two-input protective relay having a protection area on an impedance plane. , a protective relay that inputs current and voltage signals of the power system and provides an operational output when the impedance of the power system exists within a predetermined protection area on the impedance plane; Inspection signal application means for applying a current and voltage signal that moves in a direction parallel to the basic axis as the inspection signal; storage means for storing operation and non-operation conditions of the protective relay; repetition means for causing the inspection signal application means to sequentially apply inspection signals having a plurality of different impedance trajectories parallel to the basic axis; operation of protective relays,
1. An inspection device for a protective relay, comprising: output means for outputting characteristics of the protective relay on an impedance plane according to stored information of non-operation.