JPH0432612B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a digital protective relay, and more particularly to a digital protective relay that has a compact setting section and that has a large number of relay elements.

[Technical background of the invention]

The technology of applying microcomputers to protective relays that protect power systems is widely known. However, in conventional analog protective relays,
Since each relay element has an independent hardware configuration, the setting values that determine the operating values of these relays are individually set by a setting section provided for each relay element.

On the other hand, in a digital relay, a single hardware configuration can usually have a relay operation determination function equivalent to several conventional relay elements. In digital relays that have a determination function for an extremely large number of relay elements, it is possible to miniaturize each operation determination circuit by providing a setting section for each relay element, but it is not possible to reduce the size of the setting section. This would impede the overall miniaturization of the relay. Therefore, various methods have been proposed to reduce the size of the settling section and improve the reliability of the circuit.

Here, the conventional digital relay configuration when one digital relay protects multiple power lines and the protection relay elements of each power line are almost the same is described as the first example.
This will be explained using figures.

In FIG. 1, a plurality of electrical quantities v and i from the power system are input to a filter circuit 1 for mainly extracting fundamental wave components. The output of this filter circuit 1 is input to a sample hold circuit 2 in order to simultaneously sample all inputs, and the output of the sample hold circuit 2 is further input to a multiplexer circuit 3, and is sequentially and serially output to an analog/digital converter circuit 4. Analog/digital conversion is performed.

Here, the analog/digital converted relay input is transferred to the data memory (MEMO) in the arithmetic processing unit 6 by the direct memory access control circuit 5.
sent to. This arithmetic processing unit 6 uses the digital value voltage and current information sent from the direct memory access control circuit 5 and the setting value read from the setting section 7 via the bus 15 to determine the operation of the relay, and determines the relay operation. When it is determined that the relay output 8 is determined, the relay output 8 is derived.

The above-mentioned settling section 7 has the configuration shown below. That is, the setting section 7 includes the storage section 12 and the setting operation section 1.
3. Write switch 14, encoder (hereinafter
COD) 11, the first selection means 9 and the second
It consists of selection means 10. The output S9 of the first selection means 9 selects a power transmission line to be set from among a plurality of power transmission lines, and the second selection means 9 selects a relay element.
The output S10 of the selection means 10 is inputted to the COD 11. And COD11 is each output S9 and S
10 is input, converted into a pure binary number, and further outputs an address signal S11 specifying an address to the storage section 12. The setting operation unit 13 is constituted by a digital switch, etc., and sets a setting value to be set, outputs the value as data S13, and inputs it to the storage unit 12 as data. The write switch 14 outputs a write signal S14, and the first
Setting value data S13 from the setting operation section 13 is written into the storage section 12 in accordance with the address value of the address signal S11 selected and determined by the selection means 9 and the second selection means 10. Note that the first selection means 9 is composed of, for example, a rotary switch or the like, and includes contacts corresponding to the number of selectable power transmission lines, an output signal line of these contacts, and a common terminal connected to the OV. By selecting the power transmission line to be settled, the common terminal and the selected contact are connected, and the signal on the output signal line is output as "0". The second selection means 10 is also similar to the first selection means 9, and is composed of a relay element contact, a signal line of the contact, and a common terminal.

[Problems with background technology]

According to the conventional device shown in FIG. 1 mentioned above,
To set the relay element, first,
The first selection means can select the power transmission line to which the relevant relay element belongs, and then the second selection means can select the relevant relay element from among a plurality of relay elements, and therefore the setting The section can be made smaller.

However, the conventional device having the above configuration has the following drawbacks.

That is, if all or part of the power transmission lines selected by the first selection means have relay elements with the same setting value, the relay elements with the same setting value are set all at once. It is desirable to perform operations to facilitate maintenance and operation.

By the way, when setting the distance relay element in parallel two-line transmission line protection, if the two-line transmission line is balanced, it is possible to perform the same setting for each relay element on both lines. If a T-branch load is connected to the electric line, different settings are required for each of the first and second lines. Therefore, when considering a standard device, it is necessary to be able to deal with both cases where the above-mentioned same setting is possible and cases where individual setting is required. However, according to the conventional device, the circuit configuration requires that all the power transmission lines that can be selected by the first selection means 9 be individually set, so the setting operation cannot be performed for multiple power transmission lines at once. Therefore, the number of settling operations increases and is complicated, and therefore, the settling operations are prone to errors.

Such a setting method is likely to cause a setting error in the setting value, and furthermore, there is a risk of malfunction or malfunction of the relay, and it is difficult to standardize the device.

[Purpose of the invention]

The present invention was made with the aim of solving the above-mentioned problems, and when the relay elements of a plurality of power system equipment are stored together, it is possible to solve the problem individually for each power system equipment. too,
Another object of the present invention is to provide a digital protective relay that can be easily set even when a plurality of power system facilities are installed at once.

[Summary of the invention]

The present invention includes a first selection means capable of selecting a single or collective selection from among a plurality of power system facilities, and a second selection means capable of selecting a relay element applied to each power system facility. If the output of the selection means indicates that a single power system equipment is selected, the setting value is written only to the address of the memory area corresponding to the relay element of the equipment in the storage unit, and If the output of the first selection means indicates that multiple power system facilities are to be selected at once, all the memories in the memory area corresponding to the relay elements of each power system facility in the storage section are By writing and storing setting values, it is possible to perform a setting operation for each single power system facility or for a plurality of power system facilities collectively.

[Embodiments of the invention]

Examples will be described below with reference to the drawings. FIG. 2 is a block diagram of one embodiment of the digital protective relay according to the present invention. In this case, only a portion corresponding to the setting section 7 is shown, and the other structure is the same as that in FIG. 1. Therefore, the reference numeral 7A in FIG. 2 corresponds to 7 in FIG. Reference numerals 13 to 15 in the figure correspond to those in FIG. Note that 9A and 10A correspond to the first selection means 9 and the second selection means 10, 11A corresponds to the encoder circuit COD11, and 12A and 12
B is a storage section divided into two parts and corresponds to 12.

In this example, a two-circuit power transmission line with a high resistance grounding system is to be protected, and a three-stage time-limited differential relay system is used for short circuit protection, and a ground fault direction relay system is used for ground fault protection. In this example, a reactance element (hereinafter referred to as O ₁ ) in the first stage, a reactance element (hereinafter referred to as O ₂ ) in the second stage, and a Mori relay element (hereinafter referred to as SU) are used as relay elements for short circuit protection. For ground fault protection, we will explain the case where a ground fault direction relay element (hereinafter referred to as DG) is provided.

In FIG. 2, the first selection means 9A is means for selecting only one of the first line, the second line, and both lines collectively, and each selection is made at each contact point T91, T92, and T93. Compatible. And each signal S9 from each of the contacts T91 to T93
1, S92, and S93 are input to a selection circuit (hereinafter referred to as SEL) 16. second selection means 10A,
It is means for selecting only one of the relay elements O ₁ , O ₂ , SU and DG, and each selection corresponds to contacts T101, T102, T103 and T104. Signals S101, S102, S103, S10 from each of the contacts T101 to T104
4 is input to COD11A. The SEL 16 is a well-known circuit that receives signals S91 to S93 from the first selection means 9A and outputs selection signals S161 and S162, and the relationship between its inputs and outputs has the sign relationship shown in FIG.

That is, when the first line, the second line, and both lines are selected at once from the first selection means 9A, the above-mentioned
The inputs of SEL16 are 110, 101, and 011, respectively, and the selection signals S161 and S162 at this time are 10 and 10, respectively.
01, 11. COD11A is the signal S101~S
104, and set the weight of the data in S104,
The signals S103, S102, and S101 are converted into pure binary codes and a signal S11A is output. That is,
When each relay element O ₁ , O ₂ , SU and DG is selected, the inputs of COD11A are 1110, 1101,
1011, 0111, and the signals S11A at this time are 00, 01, 10, and 11, respectively. First storage unit 12A
Then, the selection signal S161 from the SEL16 is used as the selection input, and the signal S11A from the COD11A is used as the selection input.
Input each as an address value. Similarly, in the second storage section 12B, the selection signal S from the SEL 16 is
162 is a selection input, and the signal S11A from the COD 11A is inputted as an address value.

The above-mentioned first selection means 9A is composed of a rotary switch or the like, and is connected to contacts T91 to T9n corresponding to the selectable number and signals S91 to S9n and OV sent by signal lines from these contacts. When a power system equipment such as a power transmission line to be set is selected, the common terminal _T0 and the selected contact are connected and the output signal is output as " ₀ ". It is something that will be done.
The configuration of the second selection means 10A is also the same as that of the first selection means 9A, and each relay element contact T1
01 to T10n, signals S101 to S10n, and a common terminal _T0 .

Next, the operation will be explained. In FIG. 2, when the first line is selected by the first selection means 9A, the signals S93 to S91 become 110, and the output signals S161 and S162 of the SEL 16 that receive this become 110.
10, the first storage unit 12A is selected, and the second selection means 10A selects each relay element O ₁ ,
When O ₂ , SU, and DG are selected, COD 11A becomes 00, 01, 10, and 11, respectively, and these become addresses, so the set values for each relay element of the first line are stored in the first storage unit 12A. are respectively stored in the address areas. Also, the first selection means 9
When the line is selected by A, signals S93~
S91 becomes 101, and the output signals S161 and S162 of SEL16 that receive this become 01 and the second storage unit 12B is selected. Therefore, as in the case of the first line, each of the second lines Setting values regarding the relay elements are stored in the second storage section 12B. Similarly, when both lines are selected at once by the first selection means 9A, the signals S93 to S91 become 011, and the output signals S161 and S162 of SEL16 become 11.
The output S11A of the COD 11A when both the first and second storage units 11A and 11B are selected simultaneously and the relay elements O ₁ , O ₂ SU, and DG are selected by the second selection means 10A. are respectively 00, 01,
10, 11, which becomes the address. Therefore, the same setting value for both lines regarding each relay element of the first and second lines is stored in the address area of the first storage section 12A and the second line. Storage unit 12
It is simultaneously written and stored in two locations in the address area of B.

In short, for relay elements that require different settings for each line, the first selection means selects the first or second line alone, and the first line is stored in the first storage unit. For the second line, the address is stored in the second storage unit, and the relay element selected from the second selection means is input to each corresponding storage unit, so the setting for each line is performed. It becomes possible. On the other hand, for relay elements that perform the same setting on both lines, both lines are selected at once by the first selection means, and the first and second
Each address is stored in the storage section of , and each relay element is selected by the second selection means, thereby making it possible to perform the same setting for the relay elements of both lines.

FIG. 4 shows another embodiment of the digital protective relay according to the present invention, and like FIG. 2, only the setting portion is shown.

In this embodiment, a part of the selection signal from the SEL 16 is used as an address signal, and the rest is stored as data in the storage section together with the setting value. The symbol 12C in the figure corresponds to 12 in FIG. 1, and the other symbols correspond to those in FIG.

In FIG. 4, the signal S161 from SEL16
is input to the storage section 12C together with the signal S13 from the setting operation section 13, and is stored together with the setting value. Also, the signal S162 is used as the most significant bit.
It is input to the storage unit 12C as an address value together with the signal S11A from the COD 11A, and indicates the address where the set value is stored. Other configurations are the same as in FIG. 2.

Next, the operation will be explained. When the first line is selected by the first selection means 9A, the signal S93
~S91 becomes 110, and the output signal S of SEL16
161 and S162 become 10. As mentioned above, since the signal S162 is the most significant bit of the address,
The setting value from the setting operation section 13 is written and stored in the memory area of the storage section 12C where the most significant bit of the address is "0" together with the signal S161 which is "1". The second selection means 9A selects the second
When the line is selected, signals S93 to S91
becomes 101 and the output signal of SEL16 S161,S
162 becomes 01, the setting value from the setting operation section 13 is sent to the memory area where the most significant bit of the address of the storage section 12C is "1", and the signal S1 is "0".
61 and is written and stored. Further, when both lines are selected at once by the first selection means 9A, the signals S93 to S91 become 011, and the SEL
Since the output signals S161 and S162 of 16 become 11, the setting value from the setting operation section 13 is stored in the storage section 12C.
is written and stored in the memory area where the most significant bit of the address is "1" together with the signal S161 which is "1".

FIG. 5 is a combination diagram of addresses, stored signals, and setting values in the storage section. To explain this further with reference to FIG. 5, the setting value of the first line is written in the memory area where the most significant bit of the address is "0" with the signal S161 being "1", and similarly The setting value for the second line is written in the memory area where the most significant bit of the address is ``1'' with the signal S161 being ``0'', and the setting value for both lines at once is written in the memory area where the most significant bit of the address is ``1''. The signal S161 is written in the state of "1" in the memory area where the signal is "1". In the case of a set value for both lines at once, the arithmetic processing unit 12C transfers the set value from the memory area where the most significant bit of the address is ``0'' to the memory area where the most significant bit of the address is ``0''. Each relay element of the first line and the second line will have the same setting value.

FIG. 6 is a flowchart for processing in the arithmetic processing section. First, in step 17, a set value and a signal S161 are applied to the data stored in each address whose most significant bit is "1".
If the signal S161 is "0" in step 18, the set value is for the second line, and the processing for that address ends. However, if the signal S161 is "1", the process moves to step 19, where the most significant bit is "0" and the other bits write the set value read out in step 17 and the signal S161 to the same address, and in step 20, the most significant bit is written to the same address. The signal S161 of the original address whose upper bit is "1" is changed to "0" and the processing of that address is completed. By performing the above procedure for addresses 100 to 111, the set value written in the memory area where the most significant bit of the address is "1" by selecting both lines at once will be changed to the value where the most significant bit of the address is "0". ”, and the signal S161 indicating that it is a set value by batch selection also changes from “1” to “0”.
After the above processing by the arithmetic processing unit 12C, the setting value and signal S161 stored in the storage unit 12C are in the same state as when the first and second lines are set separately. Through the processing of the arithmetic processing section described above, the settling operation can be performed for the first or second line alone or for both lines at once.

FIG. 7 shows still another embodiment of the digital protective relay according to the present invention, and similarly to the above, only the setting portion is shown. The symbols in the figure correspond to those in FIG . 2 and FIG .
7B in the figure, and the storage unit 12D is 12C in FIG.
corresponds to

In this embodiment, when a signal from SEL is input, a memory area is provided in the storage section in which the first line and the second line are respectively stored, and when each line is selected individually, the memory area for each line is The information is stored in a predetermined memory area, and when both lines are selected, it is written in each of the memory areas in sequence.

In FIG. 7, selection signal S1 from SEL16
61 and S162 are input as control signals to the storage section 12D. When the signals S161 and S162 are 10 (when the first line is selected), the storage unit 12D writes the setting value from the setting operation unit 13 to the memory area where the most significant bit of the address is “0” (the first line is selected). Addresses 000 to 011 in Figure 8), signal S16
1. If S162 is 01 (when selecting the second line)
writes the setting value from the setting operation unit 13 to the memory area whose most significant bit of the address is "1" (100 to 111). Furthermore, when the signals S161 and S162 are 11 (when 2 lines are selected), for the two areas, the memory area where the most significant bit of the address is "0" and the memory area where the most significant bit is "1",
It is configured to sequentially write the setting values from the setting operation section 13. The configuration of other parts is the same as the embodiment shown in FIGS. 2 and 4. As described above, the setting operation can be performed for the addresses shown in FIG. 8, either individually for each of the first and second lines or for both lines at once.

FIG. 9 shows still another embodiment of the digital protective relay according to the present invention, showing only the first selection means and selection circuit in the setting section.

In this embodiment, the first selection means, which used to be a rotary switch, is replaced with two toggle switches. Code 9 in the diagram
B corresponds to 9A, and 16A corresponds to 16 in each of the above embodiments.

In FIG. 9, the first selection means 9B is means for selecting one or both of the two lines to be protected, and the toggle switch SW1 is the first selection means.
The toggle switch SW2 corresponds to the second line, and the toggle switches SW1 and SW correspond to the second line.
Signals S91B and S92B from SEL2 are respectively input to SEL16A. and each of the toggle switches
SW1 and SW2 are "closed" when the first and second lines are selected respectively, and when the first line is selected, the signals S92B and S91B are 10 and the second line is "closed".
If the line is selected, the value is 01, and if both the first and second lines are selected, the value is 00. SEL16
A is the signal S91B, S from the first selection means 9B
92B respectively to select signals S161 and S1.
The output of 62 is the same as in each of the embodiments described above. The relationship between input and output is also the same as that in FIG. The other configurations are also the same as in each of the above embodiments.

Next, the operation will be explained. First, if you want to select only the first line, close toggle switch SW1.
By setting SW2 to "open", the signal S
Since 91B and S92B are 01, the output signals S161 and S162 of SEL16A are 10. Similarly, when only the second line is selected, the signals S91B and S92B become 10 by setting the toggle switch SW1 to "open" and the second SW to "closed", so the output signals S161 and S92B of the SEL16A S16
2 becomes 01. In addition, if you want to select the first and second lines all at once, press toggle switch SW1 and
By setting both SW2 to "close", the signal S9
Since 1B and S92B are 00, the output signals S161 and S162 of SEL16A are 11. The operation of other parts is the same as in each of the embodiments described above. Note that FIG. 10 is a diagram showing the correspondence with input signals in the selection circuit.

FIG. 11 shows still another embodiment of the digital protective relay according to the present invention, and like the previous embodiments, only the setting portion is shown. The reference numeral 7D in the figure corresponds to 7A in FIG. 2, and 9C corresponds to 9A in FIG.

In this embodiment, the selection signal is derived by opening and closing two normally closed toggle switches, and the rotary switch and selection circuit using the first selection means are omitted.

In FIG. 11, the first selection means 9C is means for selecting one or both of the two lines to be protected, and is comprised of two normally closed toggle switches SW3 and SW4. Here, the toggle switch SW3 corresponds to the first line, and the toggle switch SW4 corresponds to the second line, and the signals S91C and S91C from the toggle switches SW3 and SW4 correspond to the second line.
92C is the selection signal S161, S1 in FIG.
62, the first and second storage units 12A
and input to 12B. Then, each toggle switch SW3, SW4 becomes "open" when the first and second lines are selected, respectively, and the signals S91C, S9
2C is 10 if the first line is selected, the second
If the line is selected, the value is 01, and if both the first and second lines are selected, the value is 11. The structure and operation of other parts are similar to the embodiment shown in FIG.

In the above embodiment, the first selection means has a rotary switch or toggle switch configuration, and the second selection means has a rotary switch configuration, but the present invention is not limited to this. It is obvious that a switch configuration in which only one can be selected is sufficient.

In addition, when writing the setting value to the storage section, we have explained the case where it is automatically done by hardware, but this is not a limitation. It goes without saying that the above-mentioned hardware functions can be realized by a program by inputting the signals from the first and second selection means into the arithmetic processing section via the input device.

Furthermore, although the above explanation describes a two-circuit power transmission line as the object of protection, it can be applied in any case where multiple power system facilities each having a plurality of setting elements are to be protected. Of course.

〔Effect of the invention〕

As explained above, according to the present invention, the first selection means selects a single or collective power system equipment from among a plurality of power system equipment, and and a selection circuit that converts the output from the first selection means into a selection signal corresponding to the selected power system equipment, select a memory area for storing the set values of the applied relay elements for the specific power system equipment selected by the second selection means; By outputting , the setting value from the setting operation unit can be stored for each address in one or more selected memory areas, so it is possible to store relay elements of multiple power system equipment. In the case of a single power system equipment or multiple power system equipment at once, the setting operation can be easily performed, not only can setting errors be prevented, but also it is possible to standardize the equipment. We can provide digital protection relays that allow

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional digital protection relay, FIG. 2 is a configuration diagram of an embodiment of the setting section of the digital protection relay according to the present invention, and FIG. 3 is a correspondence diagram of input signals and output signals in a selection circuit. FIG. 4 is a configuration diagram of another embodiment of the setting section, FIG. 5 is a combination diagram of addresses in the storage section, stored signals, and setting values, FIG. 6 is a flowchart showing processing in the arithmetic processing section, and FIG. 7 is a configuration diagram of another embodiment of the setting section, FIG. 8 is a combination diagram of setting values and addresses in the storage section, FIG. 9 is a configuration diagram of another embodiment of the first selection means and selection circuit in the setting section, FIG. 10 is a correspondence diagram of input signals and output signals in the selection circuit,
FIG. 11 is a configuration diagram of still another embodiment of the settling section. DESCRIPTION OF SYMBOLS 1... Filter circuit, 2... Sample hold circuit, 3... Multiplexer circuit, 4... Analog/digital conversion circuit, 5... Direct memory access control circuit, 6... Arithmetic processing unit, 7 ,
7A, 7B , 7C , 7D ... Setting section, 8... Relay output, 9, 9A, 9B, 9C... First selection means, 10, 10A... Second selection means, 11, 1
1A...Encoder circuit, 12, 12A, 12
B, 12C, 12D...Storage section, 13...Setting operation section, 14...Write switch, 15...Bus,
16...Selection circuit, SW1, SW2, SW3, SW
4...Toggle switch.

Claims (1)

[Scope of Claims] 1. A plurality of relay elements for which the same or different setting values are set for a plurality of power system equipment, a setting operation section that sets a setting value for each of the relay elements, and each relay element. a storage unit that stores the output from the setting operation unit in accordance with the selection of the setting operation unit; a write switch that writes the setting value to the storage unit; and one of the plurality of power system equipment. A digital protective relay comprising a first selection means capable of selecting one or a plurality of them at once, and a second selection means selecting a relay element to perform a setting operation from among the respective relay elements, wherein the first
a selection circuit that inputs an output from the selection means and derives a coded output by discriminating which of the plurality of power system equipment is selected by this signal or a collective selection; a code conversion circuit which inputs the output from the selection means and outputs an address signal corresponding to the selected relay element; and a first memory into which the outputs from the selection circuit and the code conversion circuit are divided and inputted respectively. Part and 2nd
If the selected power system equipment is a single storage unit, it is stored in the corresponding memory area in one of the predetermined storage units, and if the selected power system equipment is multiple at once, it is stored in the corresponding memory area. A digital protective relay characterized by storing data in a memory area in all storage units. 2. A plurality of relay elements for which the same or different setting values are set for a plurality of power system equipment, a setting operation section that sets the setting values for each of the relay elements, and a setting operation section that sets the setting values for each of the relay elements, and a setting operation section that sets the setting values for each of the relay elements. a storage section for storing the output from the operation section; a write switch for writing a set value into the storage section; and selecting any one of the plurality of power system equipment or selecting a plurality of them at once. A digital protection relay comprising a first selection means for selecting a relay element to perform a setting operation from among the relay elements, and a second selection means for selecting a relay element to perform a setting operation from among the relay elements, the output from the first selection means being input. and a selection circuit that derives a coded output by discriminating whether this signal selects one of the plurality of power system equipment or all of the power system equipment, and inputs the output from the second selection means. a code conversion circuit that outputs an address signal corresponding to the selected relay element; and a single storage section into which the outputs from the selection circuit and the code conversion circuit are respectively input; A digital protective relay characterized in that the most significant bit of a coded output from a circuit is used as an address and other bits are stored together with a set value. 3 A plurality of relay elements in which the same or different setting values are set for a plurality of power system equipment, a setting operation section that sets setting values for each of the relay elements, and a setting operation unit that sets the setting value in accordance with the selection of each relay element. a storage section for storing the output from the operation section; a write switch for writing a set value into the storage section; and selecting any one of the plurality of power system equipment or selecting a plurality of them at once. A digital protection relay comprising a first selection means for selecting a relay element to perform a setting operation from among the relay elements, and a second selection means for selecting a relay element to perform a setting operation from among the relay elements, the output from the first selection means being input. and a selection circuit that derives a coded control signal by discriminating whether this signal is a single selection or a batch selection of power system equipment, and an output from the second selection means. A code conversion circuit that outputs an address signal corresponding to the relay element, and a single storage section into which the outputs from the selection circuit and the code conversion circuit are respectively input, and the storage section is configured to input the code from the selection circuit. The address area is divided using the most significant bit of the selected control signal as an address signal, and in the case of single selection of power system equipment, it is stored in a predetermined corresponding memory area, and in the case of collective selection of power system equipment, the address area is divided. A digital protective relay characterized by storing information in each memory area. 4 A plurality of relay elements in which the same or different setting values are set for a plurality of power system equipment, a setting operation section that sets the setting values for each of the relay elements, and a setting operation unit that sets the setting values in accordance with the selection of each relay element. a storage section for storing the output from the operation section; a write switch for writing a set value into the storage section; and selecting any one of the plurality of power system equipment or selecting a plurality of them at once. A digital protection relay comprising a first selection means for selecting a relay element to perform a setting operation from among the relay elements, and a second selection means for selecting a relay element to perform a setting operation from among the relay elements. a plurality of toggle switches having contacts; a code conversion circuit that inputs the output from the second selection means and outputs an address signal corresponding to the selected relay element; and an on/off output from the toggle switch. and a first storage section and a second storage section into which the output from the code conversion circuit is divided and inputted, respectively, and when the selected power system equipment is single, a predetermined one storage section is provided. A digital protective relay is characterized in that it is stored in the corresponding memory area in the storage unit, and in the case where a plurality of selected power system equipments are selected at once, it is stored in the memory area in all the storage units.