JPS5849028A - Protective relay unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a protection line m1iii of a power system.

Conventionally, this rice! There was something shown in Figure 1. In the figure, 1.1 is the grid power transmission II! A current transformer that transforms a current of 1 m, 2 is a transformer that converts the output level of current transformer 1, 3 is a filter that extracts the fundamental wave component from the output of transformer 2, and 4 is a digital converter that converts the output of filter 3. Declination cage: A converter for conversion, 5 is a large central processing unit (CPU) in the converter 4, 6 is a CPU 582, memory for storing the program used for the calculation process, 6 is a CPU 5
Connected to n, external s4: This is an output section that outputs a signal indicating that there is an accident. Transformation! 13-13-Output 7ti protection line II device is constructed.

Next, the operation will be explained. The current of the power transmission 111a is input to the converter 4 through the transformer @1, the transformer @2, and the filter 3, and is converted into a digital signal 8f1 large vI? %CPU5
(From 2, 1@ is sequentially loaded into the memory 64 as data.

The CPU 5 uses the data of the power transmission #1m according to a program stored in the memory 6 (=stored in 1) to perform a process of determining whether or not there is an accident in the power transmission 11111m.

If there is an accident, a signal is output from the output section 7.

Generally, the current (instantaneous value) flowing through 111 meters of power transmission is 90
There is a relationship with the previous one as shown in the following equation.

(knee ωt) + (I (ωt-90°)) 2 = I (2) ωt + (-I (2) ωt) 2 Tomi I da #t+I (2) ωt Each of the two instants wIgIJ that does not include the DC component N squared and 1 added is equal to Daisensha, 7 wave height I squared II I2.

Therefore, 1, CP, and US use the data in this attack relationship, execute the calculation as shown in the above formula to obtain 1 wave height - In such cases, it is determined that an accident has occurred.

Conventional protective relay *Wa, structured as above: Art
Since the data ζ used in the accident judgment process has the disadvantage that the reliability of the judgment will decrease if it contains a DC component due to the offset of the converter, etc. The drawback is that it requires a complicated aim to remove.

This invention is a major improvement that eliminates the drawbacks of the conventional system as described above, and includes processing to remove the DC component from input 1t172 data, and then executing an accident determination process. Second, the purpose is to provide a safety relay and electrical system that can make highly reliable accident determinations.

Hereinafter, an example of the present invention will be used to explain the conventional device.
1 will be explained with reference to - again. Note that the description of each block in the figure will be omitted since it will be repetitive.

By the way, when calculating the difference A between each instantaneous aiF gain of 180 different currents, it is as follows.

A=Ido(ωt+90)−(Igb+(ωt−90)
)=1ωt(2)9o+x*5o(2)ωt-(1-
ωt(2) 90°−1 90(to)@It) = 2Iewωt = 2I(ωt+90) Therefore, the difference A has l1t2I that is twice that of the wave height.

1 large, as a result of taking the difference as in the above formula, each instantaneous price includes 1t1
Since the DC component with the same components is removed, the difference A is only the fundamental wave fraction, and the wave height I can be determined more accurately than the difference A.

The program required for such calculations is stored in the memory 6 8
n'''C, the data of the power transmission layer 1a is also sequentially transferred to the memory 6 via the converter 4.The CPU 5 executes the above-mentioned calculations in a certain cycle according to the program and data in the memory 6. Then, the wave height IIl is released, and the presence or absence of an accident is determined in the same manner as in the case of the US. If there is an accident, a signal is output from the output section 7.

As described above, the present invention (:) performs accident determination processing by removing DC component errors included in input data, so it is possible to improve the accuracy of determination.

[Brief explanation of the drawing]

The figure is a block diagram of the protective relay fIw. 1... Current transformer, 2... Transformer, 3... Filter,
4...Converter, 5...Central processing 1i-16...
- Memory, 7 - Output section, 8... Protection network 1 equipment.

Claims (1)

[Claims] The first data of 11 large currents detected sequentially from the grid and 18
A first program that calculates the difference between the jIl data and the jIl data that has a phase difference relationship of 0 and generates 1112 data consisting of the fundamental wave component of the current, and a second program that detects an accident in the system based on the iJ2 data. A large memory ζ that stores 2 programs, and a central processing unit that executes the first and second programs and orders a hole output to maintain the system when the accident order is detected! Hole I with 1ml
! Relay electric @M.