JPS6056373B2 - Phase comparison relay device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase comparison relay device used for power transmission line protection.

Conventional phase comparison relay devices for power transmission lines have been used only in systems with power supplies at both ends or systems with fixed power supplies at one end.

Even when applied to a double-ended variable power supply system, a method is adopted in which only the power terminal is disconnected, and the non-power terminal is disconnected by a transfer disconnection, but when the transmission channel is limited It was impossible to cut both ends at the same time. As mentioned above, the object of the present invention is to eliminate the need for a special transmission channel even in a system that handles a variable power supply at both ends, and to use a conventional transmission channel to prevent simultaneous disconnection at both ends in the event of an internal accident. The object of the present invention is to provide a possible phase comparison relay device.

Before entering into the description of the present invention, a conventional example that is the background of the present invention will be explained in detail.

FIG. 1 shows a schematic diagram of a conventional phase comparison relay device. Conventionally, by controlling point d in FIG. 1 according to the power supply conditions of the system, it was fixed whether it was treated as a power source end or a variable power source end. In Figure 1, 1 is the protected transmission line, 2 is the current transformer (C
T), 3 is the input transformer of the relay, 4 and 5 are level detectors (LD), 4 outputs the output only when the instantaneous value of the current exceeds a certain level H, and 5 is the input transformer of the relay, and 5 is the output when the instantaneous value of the current exceeds a certain level H. The output is output only for a time that does not exceed a certain level L.
6 is a switching control unit for fixing the above-mentioned power supply end treatment and variable power supply end treatment; 7 is L, . A transmission delay compensation circuit compensates for the transmission delay time in order to compare the phases of the output of the H level detector and the received signal C sent from the opposite end, and 8 is a time measurement circuit for phase comparison.

Note that a is a relay output and b is a transmission signal. As is clear from FIG. 1, the conventional transmission signal is either the output of the L level detector 5 or the output of the H level detector 4, and for this reason, the power supply conditions at both ends of the system vary widely. However, this method could not be used, and the method used was to fix the power terminal as described above.

By improving the conventional phase comparison relay equipped with such two sets of level detectors, the present invention enables simultaneous operation at both ends even when applied to a system where the background power conditions at both ends change widely. There are things that make it possible to disconnect. 1 is a block diagram illustrating an embodiment of the present invention with reference to the drawings. FIG.

FIG. 2 is a block diagram showing one embodiment of the present invention. In the figure, the same parts as in FIG. 1 are indicated by the same symbols. 9,10
11 is a timer for determining whether the signal received from the other party's terminal is at L level or H level, and 11 is a circuit that reproduces the L level output time of the other party's signal from the outputs of timers 9 and 10. The received signal processing circuit will be described later. part of,
12 is a rectangular wave generation circuit (
RO circuit). Although FIG. 2 only shows one terminal of the power transmission line, the same device is installed at the other terminal as well. However, the same thing mentioned here means that the equipment is installed. This includes slight differences in characteristics that may be required depending on the power supply conditions at the location. In FIG. 2, the transmitted signal b! This is the OR of the processed output of the 1L level detector 5 and the output of the )j level detector 4. This relationship will be explained with reference to FIG. In FIG. 3, three types of transmission signals are shown depending on the relationship between the LlH level and the magnitude of the current 1.
Figure 3a shows the transmission signal when the current is small and the current 1 is below the L level, Figure 3b shows the transmission signal when the current 1 is L〈I〈H, and Figure 3c shows the transmission signal when the current 1 is below the L level. The transmission signals are respectively shown when H is greater than the H level and H<1.
FIG. 4 is a diagram showing the main part of FIG. 2 to show the response of the processing circuit for the received signal from the partner terminal. In the figure, c
is the received signal from the other party's terminal. Tl and T2 are timers that are a combination of an on-delay timer and an off-delay timer, respectively. That is, as shown in FIG. 5, the timer T1 is activated after the time Tll has elapsed since the reception signal C is applied, and becomes "1", and after the reception signal C becomes 0, the timer T1 is activated.
This timer returns to 0 after 2 elapses. Similarly, the timer T2 is a timer that becomes ``1'' after a time T2l has elapsed after reception, and becomes ``0'' after a time t has elapsed after no reception is received. [F] [F] The terminals are temporary terminals used to distinguish between high-level signals and low-level signals from the other terminal.Also, A, 口, and C are symbols used for explanations.Figure 5 shows , the response example in FIG. 4 is expressed using three cases of the transmitted signal in FIG.
] output is ゜゜0 - For explanation, the state of point A is ゜゛, the state of point 口 is ゜゜1゛, and the state of point C is ゜゜0 - the state of terminal [F] is "゜1". It shows that there is. Similarly, FIG. 5 b and FIG. 5 c show the state of each location depending on the magnitude of the current 1. By the way, the timers Tl and T in Fig. 4
The time 2 is set to be larger than the time width of the rectangular wave of the rectangular wave generating circuit 12 in FIG. 2, and the time width of the rectangular wave is made as small as possible within the transmission capacity of the transmission device.

For example, if the transmission capability of the transmission device is 1 KHz, the width of the rectangular wave should be about 17 ns (500 Hz), and in this case, the timer of the received signal processing circuit needs to be set to a time slightly larger than 1 ms. To determine whether an accident occurs inside the protected area or an external accident, the reception signal from the other terminal is determined by checking the level L of the other terminal.
．． The waveforms of [F] and [F] for H, and the L. ．． H
This can be done by comparing the phase of the output signal with the waveform after transmission delay compensation. That is, FIG. 6 shows a waveform diagram showing the response of the apparatus of the present invention shown in FIG. 2 when an external accident occurs, and FIG. 7 shows a waveform diagram showing the response when an internal accident occurs. Internal faults and external faults are determined by phase comparison between the H level signal at the own end and the L level signal received from the other end, and the L level signal at the own end and the received signal from the other end. Output is output by ORing the phase with the H level one.

Hereinafter, three types of cases will be described in which the magnitude of the current in the system is higher than the H level, between the H level and the L level, and lower than the L level.

FIG. 6 is an example of an external accident, and shows the output of the phase comparison of the A terminal.

As is clear from Figure 6, the H level of the phase comparison relay at its own end and the L level at the other end, and the L level at its own end and the H level at the other end.
The level phase comparison signal output does not appear, indicating normal operation.
The response of the relay at the B terminal is the same as that of the relay at the A terminal. In addition, Figure 7 shows an example of an internal accident.The current input from either terminal must necessarily be at H level or higher, so for the sake of explanation, the current at A terminal is set at H level or higher, and the current at A terminal is set at H level or higher. It shows up to the phase comparison signal output of the relay.

The presence of this phase comparison signal output indicates that an internal fault has been detected. In the case of Figure 7c,
Since the current at electric station B is below the L level, the transmission signal from electric station B continuously transmits ゜"0゛."

On the other hand, since the current at electric station A is higher than the H level, the transmission signal is an alternating signal of a rectangular wave and an intermittent signal. Furthermore, since the received signal from the A electric station is a continuous "0" signal from the other end, the receiving section classifies the L level signal as a continuous "1" and the H level signal as a continuous "0". Therefore A
The terminal phase comparison relay does not output a phase comparison output between the L level signal at its own end and the H level signal received from the other end, but
An internal fault can be determined based on the output of the phase comparison between the H level signal at the own end and the L level received signal from the opposite end. At this time, the phase comparison relay of electric station B is
level signal and the L. level signal transmitted from A electric station. ．． H
Since the phase of the high-level signal is compared with the H-level signal, it can be determined that there is an internal accident at the same time as the electric station A.
The case of Fig. 7b shows the case where the current at electric station B is above the L level and below the H level, but in this case also, Fig. 7c
At the same time, electric station A compares the phase of the H level signal at its own end with the L level signal from the other end and outputs it, while electric station B outputs the L level signal from its own end at the other end. H from
By comparing the phase with the level signal, it is determined that it is an internal accident.

In the case of Fig. 7a, the current at electric station B is higher than H level, but in this case, the transmitted signal at both ends is an alternating signal of a rectangular wave and an intermittent wave, and the received signal is also at L level and H level. The waveform will be as shown in the figure. Therefore, the phase comparison is performed by comparing an H level signal at the own end and an L level signal at the other end, and between an L level signal at the own end and an H level signal at the other end.
The output of each phase comparison will be output and it will be determined that it is internal. In the above explanation using the waveform diagram in FIG. 7, the current at electric station A is fixed at H level or above, but even if the current at electric station A is below H level and the current at electric station B is above H level, Needless to say, it can also be determined that it was an internal accident. Instead of the intermittent signal in the above explanation, it may be changed to a level.

For example, by changing the level of the transmission signal between an L level signal and an H level signal and transmitting at a frequency corresponding to this level, the receiving end can distinguish between an L level signal and an H level signal. This is shown in FIG. However, in this case, L
The difference between level and H level signals is not the timer but the F/V.
Needless to say, it is necessary to use a level detection circuit after passing through a converter. Further, in the above explanation, the time when there is no L level signal is treated as an intermittent signal, but the same effect can be applied even if the time when there is an H level signal is used as an intermittent signal.
Also, in the above explanation, L. ．． Although the polarities of the H level detectors were made to be different, it is not necessary to make the polarities particularly different.

As described above, according to the present invention, regardless of whether the present invention is used in a double-ended power supply system, a single-ended variable power supply system, or a double-ended variable power supply system in which the backing power supply at both ends changes widely, the H level of the own end is always maintained. In order to simultaneously compare the phases of the L level signal and the L level signal of the received signal from the other end, and the L level signal of the own end and the H level signal of the received signal from the other end, both ends may be disconnected at the same time. becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an outline of a conventional phase comparison relay device, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIGS. 3 a to 3 c show the operation of the device in FIG. Waveform diagram for explanation; Figure 4 is a circuit diagram showing the received signal processing circuit; Figure 5 is a waveform diagram for explaining the operation of the circuit in Figure 4; Figures 6 a-c are for external accident occurrence. FIG. 7 is a waveform diagram for explaining the relay operation when an internal accident occurs, and FIG. 8 is a waveform diagram for another embodiment of the present invention. 4...H level detector, 5...L level detector, 6a...NOT circuit, 7...
・Transmission delay compensation circuit, 8...Time measurement circuit, 9
, 10... Timer, 11... Reproduction circuit, 12... Rectangular wave generation circuit.

Claims (1)

[Claims] 1. In a phase comparison relay device that protects a power system by providing the same relay device at each electric station, a first level detection circuit having a predetermined detection level; a second level detection circuit having a detection level smaller in absolute value than the detection level of the level detection circuit; a first signal corresponding to the output of the first level detection circuit; and an output of the second level detection circuit. a transmission circuit that transmits a second signal corresponding to the second signal to the other end via the same transmission path; and a received signal processing circuit that separates the first signal and the second signal from the received signal received from the other end. , compares the phase of the first signal of the own end with the second signal of the opposite end, and compares the phase of the second signal of the own end with the first signal of the opposite end, and outputs according to the OR condition. A phase comparison relay device comprising a phase comparison circuit. 2. Claims characterized in that the transmitting circuit is a circuit that transmits the first signal and the second signal to the other end via the same transmission path by distinguishing between continuous signals and intermittent signals. The phase comparison relay device according to item 1. 3. Claim 3, characterized in that the transmitting circuit is a circuit that transmits the first signal and the second signal to the other end via the same transmission path by providing a difference in frequency and distinguishing between the two. The phase comparison relay device according to item 1. 4. The phase comparison relay device according to claim 2, wherein the received signal processing circuit is a circuit that uses a timer to separate the first signal and the second signal from the received signal. 5 Claims characterized in that the received signal processing circuit introduces the received signal into a frequency-voltage converter and separates the first signal and the second signal by determining the level of the output. The phase comparison relay device according to item 3.