JPS60183933A - Protective relay device - 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 [Technical Field of the Invention] The present invention relates to a protective relay system for protecting an electric power system.

[Prior art]

A step-out protection relay device that detects whether the system oscillation is a stable oscillation or a step-out when an accident occurs in the power system and the system oscillates after the accident is cleared will be described below.

FIG. 1 is a power system diagram schematically showing a power system, where 1 indicates a back power source at the a end and 2 indicates a back power source at the b end. 3゜4 is the bus bar at the end a, 5 and 6 are protective relays (hereinafter referred to as relays) 9
．． 10 is a current transformer that introduces current, 7 and 8 are relays 9 and 1
0 is a transformer that introduces voltage, and 11 is a power transmission line.

When the phase angle θ of current and voltage is measured at the end a, active power P = VIct1sθ, reactive power Q = VI
It is determined by glnθ. As shown in Fig. 2, the active power P and the reactive power Q change as the phase difference angle φ between the power supplies 1 and 2 at both ends changes, and the active power P is φ=900 and the reactive power Q is φ=180.
It reaches a local maximum value at .degree., and becomes equal at point A in the figure. Also, when the horizontal axis is active power P and the vertical axis is reactive power Q, P,
The Q locus is a circle as shown in Figure 3, and point A in the figure is φ=
900 is shown. Generally, power systems are operated with a phase difference angle of 90° or less, and if the phase angle exceeds 90°, step-out occurs. That is, in order to detect the tax adjustment, it is better to calculate the active power P and the reactive power Q from the voltage and current at the power source end, and to detect when the P and Q trajectories exceed 90 degrees.

Although it is preferable to detect the shift adjustment when the P-Q locus exceeds 90° as described above, it is not possible to detect the center point of the step-out in this state.

In addition, with a conventional device, the voltage phase φ at both ends is compared, and the phase φ=1
Although there was an internal determination when the phase became 80°, it could not be made when the phase φ was around 90°, that is, at the time of tax adjustment prediction.

[Summary of the invention]

In view of the problems of the prior art as described above, the present invention provides a protective relay system that can accurately detect the center point of a tax adjustment at the time of predicting a step-out and perform optimal system separation for a step-out. It is an object.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 4 to 7.

FIG. 7 shows a block diagram for calculating the amount of electricity according to the present invention. 4a and 5a are input signal voltages and currents as electrical quantities from the own end of the system, and 7a is an input electrical quantity 4a.

5a is a first calculation unit that performs calculation processing on active power P and reactive power Q; 8a is a second calculation unit that creates a string generated from the trajectory of active power P8 and reactive power Q at each time; 9a 10a is a determination unit that determines the direction change of the above-mentioned law and outputs a change pattern 91a of the string quadrant data, and 10a is a pattern determination unit that inputs the change butter 91a of the string quadrant data and the output of the change pattern data unit 11a on the other end side. In the processing section, lla indicates a change pattern data section that sends out string quadrant data at the other end relay 10, and 12 indicates a comprehensive judgment data section that outputs section detection data of the center point of step-out.

When the tax center point exists between ends a and b, the P-Q locus is shown in Figure 4. If it is on the back power source 1 side of the own end, it is as shown in Figure 5, and the back power source 2 of the b end is If it is on the side, it will be as shown in Figure 6. FIGS. 4, 5, and 6 (a) show the self-end, and f→ shows the locus at the b-end. Note that in FIGS. 4, 5, and 6, A represents a point at φ=90°, and B represents a point at 180°.

Now, in FIG. 4(a), when the P-Q locus is moving from the origin to point A, it is assumed that the locus is moving in the direction of the first quadrant. From point A to point B is the direction of the second quadrant, and similarly in Figure 4 (c), from the origin to point A is the direction of the second quadrant.
The direction from point A to point B is the first quadrant. In FIG. 5(A), the direction changes from the direction of the fourth quadrant to the direction of the third quadrant. These quadrant directions are treated as quadrant vectors, and this quadrant vector [
1→2:), [2→1].

When a change of [4→3] or [3→4] occurs, it indicates that φ=90° has been exceeded. In the self-end relay shown in Figure 1, the quadrant vector [
When a change from 1 to 2] occurs and the quadrant vector transmitted from the b-end Ray changes from the quadrant vector [2 to 1], it is determined that there is an out-of-step center point inside the b-end Ray. If the quadrant vector is quadrant vector [3→4], it is determined that it is outside the b end. These combination judgments are obtained by the comprehensive judgment data section 1z, and are as shown in Table 1 below.

Table 1 In the above embodiment, the own end is over 90° and the opposite end is 90°.
As shown in Table 1, when the self-end is a quadrant vector [1→2], if the b-end quadrant vector becomes [2→1], the overall judgment is internal. I can do it. That is, it is clear that an internal/external determination can be made by looking at the quadrant vector of the other end without looking at the change at the other end.

[Effects of the Invention] As described above, according to the present invention, since the quadrant vector building or its change pattern at the own end and the opposite end are compared to determine whether the center point of the out-of-step is inside or outside, the out-of-step is detected at the time of predicting the out-of-step. It is possible to determine whether the center point is inside or outside, which enables optimal system separation, and provides a protective relay system that can contribute to stable operation of the power system.

[Brief explanation of the drawing]

Figure 1 is a simulated power system diagram, Figure 2 is a-end, b-end
Characteristic diagram of active power P and reactive power Q with respect to the phase difference angle at the ends,
Figure 3 is a locus diagram of active power P and reactive power Q, Figures 4, 5, and 6 are explanatory diagrams explaining the loci of active power P and reactive power Q, and Figure 7 is one of the loci of this invention. It is a block diagram of a protective relay system explaining an example. 1.2... Back power supply, 3.4... Bus bar, 5.6...
・Transformer, 7.8...Transformer, 9...A terminal relay,
10...Other end relay, 1 piece...Power transmission line, 7a...
1st calculation section, 8a... Second calculation section, 9a... Judgment section, 10a... Pattern judgment processing section, 11a... Change pattern data section, 12... Comprehensive judgment data section. Agent Masuo Oiwa Figure 1 Figure 2 Figure 4 Figure 5 (0)

Claims (1)

[Claims] Voltage and current signals from the power system are introduced, sampled at a predetermined period, A/D converted, and digitally calculated by a microprocessor to detect tax adjustment phenomena in the power system and protect the power system. In the protective relay system,
Calculate the active power and reactive power from the above voltage and current signals, detect the locus of the active power and reactive power, detect the out-of-step of the power system from the locus of the active power and reactive power, and at the other end of the protection zone. The locus of active power and reactive power obtained from the locus of active power and reactive power at the own end is compared, and it is detected whether the center point of the step-out is within the protected area or outside the protected area, and the above power A protective relay system that protects the grid.