JP3248133B2 - Digital protective relay device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set and change the type and characteristics of an input filter by providing a digital filter means, which performs filtering processing in accordance with an arithmetic program and outputs processed results to a protective relay, and a means which variable sets the filter factor of the filter means according to the kind, etc., of a protective relay. SOLUTION: An analog input unit 1 which performs filtering processing on the quantity-of-state of a power system after sampling and A/D-converting the data, and a settling unit 2 which works as a filter factor setting means are respectively mounted on different substrates. The units 1 and 2 are connected to each other via a system bus 3 and form an input processor. A settling panel 4 is connected to the settling unit 2 as an external inputting means. A DSP 17 of the analog input unit 1 function as a digital filter means, which performs filtering processing on the inputted quantity-of-state data. Therefore, the type and characteristics of the filter can be set or changed arbitrarily and easily, by inputting filter factors from the settling panel 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital protection relay device, and more particularly to a power system state quantity (voltage,
And the like having a function of digitally filtering current and the like.

[0002]

2. Description of the Related Art Conventionally, digital protection relays have been published in IEEJ Magazine Vol. 105, No. 12 (P1158-P1160) or Hitachi Review V.
OL61, No. 11 (P19 to P24) are known. According to these, an input filter for processing input state quantity data such as voltage and current is constituted by an RC active filter, and is based on digital data which has been subjected to analog / digital (A / D) conversion after filtering. The protection relay operation is being performed.

[0003]

In the above prior art,
Since the configuration is such that the state quantity data is processed by the hardware input filter composed of the RC active filter, there is the following problem.

Normally, filter characteristics required for an input filter differ depending on the type of protection relay and the protection target.
Therefore, various types of RC active filters must be developed and manufactured in accordance with the type of the target protection relay and the like, and standardization cannot be performed.

When changing the characteristics of the filter, it is difficult to change the characteristics because the input filter must be removed from the protection relay device and elements such as resistors and capacitors must be replaced.

[0006] In order to adjust the gain or phase of the input filter, additional hardware components such as a trimmer resistor for adjustment must be incorporated, which limits the miniaturization of the circuit device.

[0007] The object of the present invention is to standardize,
An object of the present invention is to provide a digital protection relay device capable of easily setting and changing the type and characteristics of an input filter (hereinafter, collectively referred to as an input filter type and the like).

[0008]

The present invention has the following technical means in order to achieve the above object.

[0009] That is, in the digital protection relay device for performing a protection relay operation based on the analog state quantities of the captured electric <br/> force lines from multiple channels, wherein the plurality Ji
A rewritable first memory that stores filter coefficients used for a filter operation corresponding to each channel of the channel ;
The state data of the power system that has been digitally converted is fetched, and the state data is obtained according to a predetermined filter calculation program.
A first unit having a first processor that reads a corresponding filter coefficient from the first memory and performs a filtering process on the state quantity data, and is connected to the first unit via a system bus; a second processor capable of independent operation and first processor, the plurality of channels
A second unit having a rewritable second memory for storing the filter coefficients corresponding to each channel, the
The filter coefficients stored in the second memory are stored in the first memory.
Means for transferring data to the memory.
In accordance with a predetermined filter operation program
From the first memory for each of the plurality of channels
Read out the corresponding filter coefficient, and
Filter processing and phase error for each channel
Is corrected .

[0010] Because of these features, the digitally converted state variable data of the power system is filtered by the first processor of the first unit, and a protection relay is performed based on the filtered state variable data. An operation is performed. At this time, the first processor reads the filter coefficients stored in the first memory, performing filter processing according to the filter calculation program. First
The filter coefficients stored in the memory of the second unit are transferred from the second memory by the two processors of the second unit connected to the first unit via the system bus. Therefore, by storing various filter coefficients corresponding to the type of the protection relay from the outside in the second memory, and transferring the filter coefficient corresponding to the type of the protection relay from the first memory to the first memory, A desired filter type related to the input processing can be easily set and changed. In addition, since these settings and changes can be made by software, the input filter can be standardized. Also, for some reason
Even if the data in the first memory is lost, the second
Data such as filter coefficients can be transferred from memory at high speed
It is not necessary to stop the function of the protection relay device.
I can deal with it.

Further, since the filter coefficients stored in the first memory are transferred from the second memory by the second processor, the filter type and the like can be easily changed online. In particular, analog status for each channel
The phase error that occurs when capturing the amount is calculated for each channel.
Perform filter operation processing using the corresponding filter coefficients.
And can be corrected.

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. (First Embodiment) FIG. 1 is a block diagram of a first embodiment. In this example, a selection unit 2 as a filter coefficient setting unit is mounted on a separate board for an analog input unit 1 for sampling state data of an electric power system and performing A / D conversion processing and then filtering. is there.
These units 1 and 2 are connected via a system bus 3 to form an input processing device. The setting unit 2 is connected to a setting panel 4 as external input means. Further, a relay operation unit 5 as protection relay operation means is connected via the system bus 3.

The analog input unit 1 includes a buffer amplifier 11, a sample and hold circuit (S / H) 12, a multiplexer (MPX) 13, an analog / digital (A /
D) Converter 14, random access memory (RAM) 1
5a, a timing generation circuit 16 for generating a control signal thereto, a digital signal processor (DSP) 17,
It comprises an AM 15b, a bus interface circuit 18, and a local bus 19.

On the other hand, the settling unit 2 comprises a bus interface circuit 21, a microprocessor (MPU) 22, a read only memory (ROM) 23, a RAM 24, a rewritable nonvolatile memory (E ² PROM) 25, and a set display interface circuit. 26.

Although the detailed configuration of the relay operation unit 5 is not shown, the state quantity data input and processed by the analog input unit 1 is taken in, and the relay settling data set in the settling unit 2 is taken in. , And has a function of performing a protection relay operation.

The DSP 17 of the analog input unit 1
It functions as digital filter means for filtering input state quantity data, and has the hardware configuration shown in FIG. As shown in FIG.
Is a program memory ROM 17a in which instructions (programs) are stored, a data RAM 17b, a multiplier 17c, an arithmetic unit (ALU) 17d, a general-purpose register 1
7e, a single-chip microprocessor including an address register 17f for specifying an address of the external memory, a data register 17g for transferring data to and from the external memory, and an internal bus 17h of the DSP. The program memory ROM 17a can be used as a data area. DSP is the program memory 17a
The addition, subtraction and multiplication / division can be executed at high speed based on the program stored in the. Further, by being able to perform horizontal pipeline processing, it is possible to execute not only integer data operations but also fixed and floating-point data operations at high speed. This makes it possible to easily and quickly realize a digital filter operation for repeatedly multiplying fixed or floating point data and coefficients.

Next, the contents of the digital filter means will be described. As a digital filter, an IIR filter (Infinite-extent) having a feedback loop is used.
Impulse Response (referred to as a recursive filter) and an FIR filter without a feedback loop (Finite
−extent Impulse Response, also referred to as a non-recursive filter), and both can be calculated by the DSP 17.

FIG. 3 shows an example of a digital filter.
FIG. 2 shows a configuration diagram of a second-order IIR filter (biquad filter). In FIG. 3, a multiplication unit 31 multiplies input data by a coefficient H that determines a gain of a filter, multiplication units 32 and 3 that multiply coefficients B ₁ and B ₂ that determine a pole of the filter.
3. Multiplication units 34 and 35 for multiplying coefficients A ₁ and A ₂ for determining the zero point of the filter, delay units 36 and 37 for delaying the operation data by one sample, and addition units 38, 39 and 4
0 and 41, and performs the operation of the following equation.

Wn = H · Xn + B ₁ · W (n−1) + B ₂ · W (n−2) (1) Yn = Wn + A ₁ · W (n−1) + A ₂ · W (n−2) (2) Here, Xn is digital input state quantity data at the time of n sampling, and Yn is filter output state quantity data at that time. Wn is intermediate processing data at the time of n sampling, and W (n-1) and W (n-2) are respectively
(n-1) and (n-2).

One of the features of the digital filter is that, by changing the filter coefficients A ₁ and A ₂ shown in the above equations (1) and (2), the following equations (3) to (7) can be obtained with the same configuration. , The low-pass, band-pass, notch, and all-pass filters can be realized. That is, the filter type can be changed by changing the coefficients A ₁ and A ₂ .
Further, by arbitrarily changing the filter coefficients B ₁ and B ₂ , the characteristics of the filter (for example, the center frequency f ₀ , the selectivity Q, etc.) can be arbitrarily changed. Equations (3) to (7) below
Shows the transfer function H (z) of each filter. Note that H (z) corresponds to s in the analog system.

(Low-pass filter) A ₁ = 1.0 A ₂ = 2.0

[0028]

(Equation 1)

(Band pass filter) A ₁ = −1.0 A ₂ = 0.0

[0030]

(Equation 2)

(High-pass filter) A ₁ = 1.0 A ₂ = −2.0

[0032]

(Equation 3)

(Notch filter) A ₁ = 1.0 A ₂ = −r

[0034]

(Equation 4)

Here, r = 2 cos2πf ₀ T (6-2) T: sampling period f ₀ : stop frequency (all-pass filter)

[0036]

(Equation 5)

Here, the operation of the first embodiment will be described with reference to the processing flowchart shown in FIG. 4A shows a processing flow of the setting unit 2 and the setting panel 4 of FIG. FIG. 4B shows a processing flow centered on the DSP 17 of the analog input unit 1 of FIG. (I) Step 101 The above-mentioned coefficients of the digital filter are set on the setting panel 4 by key input operation or the like. This is similar to the method of setting the set value of the protection relay. (Ii) Step 102 The filter coefficient input in step 101 is
Is written to the E ² PROM 25 via the. E ² PROM25
Is non-volatile, so even when the system goes down,
Since the input and set filter coefficients can be held, the reliability can be improved. Steps 101 and 10
Step 2 may be performed only when setting or changing the filter type or the like. (Iii) Step 103 The filter coefficient written in the E ² PROM 25 is temporarily set to M
PU 22 and then the bus interface circuit 21
To the system bus 3 via Then, the data is written and transferred to the RAM 15b via the bus interface circuit 18 of the analog input unit 1. The MPU 22 repeatedly executes this process at every predetermined sampling period T. (Iv) Step 111 The DSP 17 writes the filter coefficient in the RAM 15b into the RAM 17b inside the DSP for each cycle T described above. (V) Step 112 The DSP 17 reads digital input state quantity data written in the RAM 15a for each cycle T, and writes the data in the internal RAM 17b. The input state data in the RAM 15 a is obtained by operating the S / H 12, the MPX 13 and the A / D conversion circuit 14 in response to a control signal from the timing generation circuit 16, and inputting the state data of the power system via the buffer amplifier 11. Is converted into digital data, and one-cycle instantaneous value data such as voltage and current is divided and taken in at a predetermined sampling cycle (for example, every 30 ° in electrical angle). (Vi) Step 113 The DSP 17 executes the arithmetic processing of the above equations (1) and (2) on the input state quantity data using the fetched filter coefficients for each cycle T, and writes the result to the RAM 17b. (Vii) Step 114 The DSP 17 transmits the filter processing result obtained in step 113 from the RAM 17b to the RAM 15b
Transfer to

The relay operation unit 5 fetches the filtered input state quantity data written in the RAM 15b via the system bus 3 at a predetermined cycle, and executes a predetermined protection relay operation.

FIG. 5 shows the flow of data until the filter coefficients set from the settling panel 4 are taken into the DSP 17. As shown in the figure, the filter coefficient input from the setting panel 4 is written in the E ² PROM 25 in the same manner as the set value of the protection relay, and then transferred to the RAM 15 b in the analog input unit 1 and written. The filter coefficient written in this is stored in the RAM 1 in the DSP by the DSP 17.
7b.

The DS shown in the above steps (iv) to (vii)
A series of processes in P17 are previously stored in a mask ROM in the program memory 17b in the DSP. Naturally, the processing program of the above (iv) to (vii)
Needless to say, it may be stored in a program memory outside P17.

According to the first embodiment described above,
By inputting the filter coefficient from the setting panel 4,
Arbitrarily, the type and characteristics of the filter can be easily set or changed. Further, since various filters corresponding to the protection relay can be realized by software through the setting operation, the input processing device can be standardized.

Further, the type and characteristics of the filter can be changed online without interrupting the function of the system, and the operation rate can be improved.

Further, in order to correct errors (gain and phase errors, variations between channels, etc.) of analog input circuits (buffer amplifiers, S / H, MPX, A / D conversion circuits), a gain and a If the phase coefficient (H and B1 and B2) is adjusted for each channel, the correction of the error can be facilitated. As a result, an adjustment element (trimmer resistor or the like) can be eliminated in the analog input unit 1, and the circuit can be downsized.

(Second Embodiment) FIG. 6 shows a block diagram of the present embodiment. In the present embodiment, as a filter coefficient setting means, a ROM 6 in which filter coefficients (H, A ₁ , A ₂ , B ₁ , B ₂ ) corresponding to a desired filter type or the like are stored in advance.
Is connected to the local bus 19 of the analog input unit 1. Therefore, the filter coefficient cannot be set and changed online as in the first embodiment, but the configuration can be simplified. Components having the same configurations and functions as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

According to the second embodiment, the DSP 17
The filter coefficient in M6 is fetched, and the input state data is subjected to the filter processing as in the first embodiment.

FIG. 7 shows a processing flow diagram of the present embodiment, and FIG. 8 shows an explanatory diagram of a data flow. (I) Step 131 The DSP 17 reads out the filter coefficients set in the ROM 6 according to the digital filter operation program stored in the program memory 17a, and
Is written into the RAM 17b. (Ii) Step 132 The DSP 17 reads digital input state quantity data from the RAM 15a for each cycle T, and writes the data to the internal RAM 17b. (Iii) Steps 133 and 134 As in the first embodiment, the DSP 17 executes the filtering process using the set filter coefficient, and
Write to M15b. As described above, according to the second embodiment, the digital filter calculation program is shared, and only the filter coefficients that are different depending on the use of the protection relay and the 50 Hz system and the 60 Hz system are stored in the coefficient ROM 6.
By mounting this ROM on an analog input board, a desired digital filter can be realized. Therefore, all except for the ROM for the filter coefficient can be used in common,
Hardware standardization can be achieved.

The type and characteristics of the filter are changed by exchanging the coefficient ROM 6.

(Third Embodiment) FIG. 9 is a block diagram of a third embodiment.

This embodiment is different from the first embodiment in that
The filter coefficient setting means is incorporated in the analog input unit 1 instead of being provided in the settling unit 2. That is, a plurality of sets of filter coefficients corresponding to various filter types and the like are stored in a non-volatile memory in the DSP 17 in advance, and a desired filter coefficient is designated by a filter coefficient selecting means to be set / changed. It was done.

The hardware configuration of the DSP 17 is the first
This embodiment is the same as the embodiment, but differs in functions and the like performed based on software. That is, as shown in FIG. 10, different areas I and II of the program memory 17a are used.
Then, the filter coefficients (H, A ₁ , A ₂ , B ₁ , B ₂ ) corresponding to a plurality of sets of filters 1 to n and the filter coefficients corresponding to the input address information are read out and the same as described above. A digital filter operation program for performing the filter processing is stored.

The filter coefficient selecting means 7 includes a dip switch 51, pull-up resistors 52a, 52b,..., And a switch interface circuit 53. The switch interface circuit 53 is connected to the local bus 19. Then, the address information of the filter coefficient is generated by the open / close combination of the DIP switch 51, and is transmitted to the local bus 19 via the switch interface circuit 53.

Next, the operation of this embodiment will be described with reference to the processing flow chart shown in FIG. (I) Step 141 The dip switch 51 is used to input and set, from among the filter coefficient storage addresses M stored in the DSP 17 in advance, address information in which filter coefficients corresponding to a desired filter type and the like are stored. (Ii) Step 142 The DSP 17 fetches the address information from the switch interface circuit 53 and obtains and sets the address M of the filter coefficient selected thereby. (Iii) Step 143 As in the above embodiments, digital input state quantity data is fetched from the RAM 15a and written into the internal RAM 17b. (Iv) Step 144 Based on the set filter coefficients and the input state data, the digital filter operation of the above-described equations (1) and (2) is executed for each of the input channels 1 to N, and the result is stored in the RAM 17b. Write to. (V) Step 145 The filtered input state quantity data stored in the RAM 17b is written into the RAM 15b and sent to the protection relay operation unit 5 and the like. Note that the DSP 17 repeatedly executes the processing of steps 142 to 145 for each predetermined cycle T.

As described above, according to the present embodiment, D
A plurality of sets of filter coefficients are stored in advance in the ROM of the SP in addition to the digital filter operation program, and filter coefficients corresponding to a desired filter type and the like can be selected from the outside by a simple dip switch operation. Therefore, by storing many types of filter coefficients in advance, standardization can be performed, and the filter type and the like can be easily changed even when online.

Further, since the filter operation program and the filter coefficient are stored in the ROM inside the DSP,
Hardware simplification, low power consumption, and the like can be achieved.

It should be noted that the concept of the filter coefficient selecting means 7 of this embodiment and the concept of the nonvolatile memory storing a plurality of types of filter coefficients are combined with the concept of the first or second embodiment for standardization and the like. It is also possible.

(Fourth Embodiment) FIG. 12 is a block diagram of a main part of a digital protection relay device to which an input processing device according to the present invention is applied.

As shown, the analog input unit 6
0, a settling unit 61, and a protection relay operation unit 62. As the analog input unit 60, those of the first to third embodiments are applied, and the settling unit 61 has the same configuration as that of FIG. The protection relay arithmetic unit 62 includes a CPU 63, a data RAM 64, a program ROM 65, a settling interface 66, a digital input section DI67, and a digital output section DO.
68 is connected via a system bus 69.

With such a configuration, the analog input board 60 takes in the voltage / current signals from the power system, converts them into digital data, executes digital filter processing operation, and executes the data RAM 64 of the protection relay operation unit 62. To enter. Next, the CPU 63 fetches the input state quantity data and the set value of the relay in accordance with the relay operation program stored in the program ROM 65, and executes, for example, a relay operation as shown in the following equation (8).

[0059]

(Equation 6)

Then, the protection relay operation unit 62 performs a sequence process based on the comparison of the equation (8) to detect an accident in the power system. A known method can be directly applied to the accident detection procedure including the protection relay operation. If the result of the accident detection is an accident, a trip command is output to a circuit breaker or the like via the DO 68.

(Fifth Embodiment) A modification of the first embodiment will be described with reference to FIG. In the present embodiment, instead of directly inputting and setting the filter coefficient, information such as the filter type is input, and the filter coefficient is calculated and set by the settling unit 2 based on the information.

(I) Step 151 From the setting panel 4 shown in FIG. 1, filter characteristic constants (central frequency f ₀ , selectivity Q,
Gain H, sampling period T, etc.). (Ii) Step 152 The MPU 22 of the setting unit 2 obtains a filter coefficient according to a predetermined procedure based on the input filter characteristic constant. For example, the following equations (9) to (12) show filter coefficient calculation equations for a bandpass filter. A1 = 0.0 (9) A2 = -1.0 (10)

[0063]

(Equation 7)

[0064]

(Equation 8)

(Iii) Step 153 The filter coefficient obtained in step 152 is stored in the E ² PROM2
5 is stored. (Iv) Step 154 Here, the MPU 22 stores the filter coefficients stored in the E ² PROM 25 in the RAM 15 b of the analog input unit 1.
Transfer to Hereinafter, the DSP 1 of the analog input unit 1
7 is a RAM 15 similar to that shown in FIG.
Filter processing is performed using the filter coefficient transferred to b.

As described above, according to the present embodiment, it is only necessary to input the filter characteristic constant from the settling panel 4, so that the number of input points is smaller than the method of the first embodiment in which all the filter coefficients are input. As a result, it is possible to reduce the occurrence of input errors due to manual input and improve man-machine characteristics.

[0067]

As described above, according to the present invention, the following effects can be obtained.

First, the input state quantity data is filtered by the digital filter means, and the filter coefficients used for the filter processing are variably set by the filter coefficient setting means. It is possible to easily set and change, and standardization of the input processing device can be achieved.

According to the filter coefficient setting means configured to set the filter coefficient in the nonvolatile memory which can be rewritten via the external input means, the operability of setting and changing the filter coefficient can be improved, and the on-line operation can be performed. You can change the filter type and so on. Further, since the filter coefficient can be set and changed from outside, the standardization of the input processing circuit can be further achieved. In addition, since errors in the analog input circuit can be corrected and adjusted by using a filter coefficient input from the outside, elements for gain and phase adjustment can be eliminated, and the circuit can be downsized.

[0070]

[0071]

[0072]

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a block diagram of a DSP according to the first embodiment;

FIG. 3 is a conceptual block diagram of a digital filter.

FIGS. 4A and 4B are processing flowcharts of the first embodiment;

FIG. 5 is a view for explaining a data flow according to the first embodiment;

FIG. 6 is a block diagram of a second embodiment of the present invention;

FIG. 7 is a processing flowchart of the second embodiment.

FIG. 8 is a view for explaining a data flow according to the second embodiment;

FIG. 9 is a block diagram of a third embodiment.

FIG. 10 is a view for explaining memory contents according to the third embodiment;

FIG. 11 is a processing flowchart of the third embodiment.

FIG. 12 is an overall configuration diagram of a fourth embodiment.

FIG. 13 is a processing flowchart of the fifth embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 analog input unit 2 setting unit 4 setting panel 5 relay operation unit 6 filter coefficient dedicated memory 7 filter coefficient selection means 17 digital signal processor (DSP) 22 microprocessor (MPU) 25 rewritable nonvolatile memory (E ² PROM) 60 Analog input unit 61 Setting panel 62 Protection relay operation unit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junzo Kawakami 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Shigeru Mori 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Ban No. 1 Co., Ltd. Hitachi Kokubu in the factory (56) reference Patent Sho 60-229618 (JP, a) JP Akira 56-94923 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ , DB name) H02H 3/02

Claims (1)

(57) [Claims] In a digital protection relay device for executing a protection relay operation based on an analog state quantity of a power system taken from a plurality of channels, a filter coefficient used for a filter operation corresponding to each of the plurality of channels is stored. A rewritable first memory, captures digitally converted power system state data, reads a corresponding filter coefficient from the first memory in accordance with a predetermined filter operation program, and reads the state data. a first unit having a first processor that performs a filtering process, is connected via a system bus to a first unit, a second processor capable of independent operation from the first processor, before
A rewritable second memory that stores the filter coefficient corresponding to each of the plurality of channels .
Unit and the filter coefficient stored in the second memory to the first
Means for transferring to a memory, wherein the first processor
From the first memory according to the program
Read the filter coefficient corresponding to each channel,
Filtering the state quantity data
A digital protection relay device which corrects a phase error for each device.