JPS6281926A - Protecting relaying 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 1 of the Invention The present invention relates to a protective relay device, and particularly to a protective relay device equipped with a circuit that prevents tripping at the time of tax adjustment.

[Technical Preface of the Invention] Power line protection relay devices using distance relays may operate during severe power fluctuations or step-outs.

Therefore, it is common to be asked about a dedicated protective relay device in addition to the normal power transmission line protective relay device.

This dedicated protection relay device is installed at an appropriate position in the power system, and has the function of making an appropriate cutoff when detecting a step-out phenomenon. In order to protect against loss of synchronization by a dedicated device, the transmission line protection relay device is equipped with a circuit (hereinafter referred to as a loss of synchronization lock circuit) that prevents the loss of synchronization during tax adjustment as described below. is set up.

FIG. 3 is an RX diagram for explaining the principle of tax adjustment detection, and FIG. 4 is a block diagram of a conventional protective relay device having a tax adjustment locking function and a 1gi tripping circuit. R in Figure 3
-More characteristics with different operating ranges as shown in the diagram 1
7. Two distance relays with offset Mho characteristic 1 are provided so that the operating range of offset Mho characteristic 1 completely includes the operating range of Mho characteristic. At this time, if the impedance seen by the relay is within the operating range 1 of the offset Moh characteristic and outside the operating range 17 of the Moh characteristic for a certain period of time or more, it is determined that the impedance is out of synch, and the impedance is determined by the Moh characteristic. Prevents disconnection of circuit breaker.

In other words, in this step-out detection method, in the event of an accident, the impedance seen by the distance relay suddenly changes and the relay reaches its maximum sensitivity angle (which matches the impedance angle of the power transmission line) shown at point 10 in Figure 3. However, at the time of tax adjustment, the impedance seen by the relay is as shown by the locus 16 in Figure 3.
It focuses on gradual changes.

Now, if a step-out occurs within the protection section of the power transmission line, the impedance seen by the relay will gradually move on the R-X diagram, as shown in the impedance locus 16 in Figure 3, and first, the off-let mode will move. It enters inside characteristic 1 and produces an output "1" in circuit 1 in FIG.

On the other hand, since the output of the circuit 17 remains "0" until the locus moves inside the Moh characteristic, the output of the AND circuit 3 remains "1" for a certain period of time. This time is the time-limited relay 4
If the operation time exceeds , the output of time-limited relay 4 becomes "1".
, which is held in the flip-flop 5, produces rOJ at the output of the inverter 11, and blocks the breaker disconnection circuit. After that, the impedance locus 1G becomes mo=
When entering the special bamboo, the output of the AND circuit 3 becomes rOJ, but the holding action of the flip-flop 5 continues to prevent the circuit breaker from being removed.

Note that the holding of the flip-flop 5 is released when the impedance change at the time of tax adjustment becomes slow and the period 115i, which is outside the operating range of the Offzet I-Moh relay, becomes longer than the operating time of the time-limited relay 9.

On the other hand, in the event of an accident within the protection zone, the offset circuit 1 to Mho and the relay having the Mho characteristic operate almost simultaneously, so the time-limiting relay 4 does not produce an output, and therefore the negative circuit 1
The output of 1 remains "1" and produces an output "1" in the AND circuit 12 with the output of the relay having the mho characteristic 17,
If this is not the case, a strict removal will be carried out. Since the normal step-out phenomenon is a three-phase balanced phenomenon, that is, a phenomenon similar to a three-phase short circuit,
For this detection, one of the three representative phases, e.g. ab, bc
A relay may be installed in the ab phase of the Sca phase. However, if only one phase is installed, the step-out phenomenon can be detected reliably, but in the event of an actual accident, it may be mistakenly detected as a tax adjustment, which may prevent the circuit breaker from being disconnected.

That is, it is now assumed that the distance relay 1.17 is installed for the ab phase. Here, if a two-phase contact occurs in the bc phase, the impedance seen by the bc phase relay will be point Po in Figure 3, but the impedance seen by the ab phase relay will be 11 points in Figure 3. The tax adjustment detection circuit starts,
This results in a problem that prevents the circuit breaker from being removed after the operating time of the time-limited relay 4 has elapsed.

In order to solve this problem, the output 17 of the relay based on the Moh characteristic shown in FIG. 3 may be made into a three-phase OR output of ab%bc and ca. In this way, in order to solve the above-mentioned problem, the relay with the mho characteristic installed in the bc phase can be
It operates by looking at the impedance shown at point Po in the figure, so
The AND circuit $ does not produce an output, and the time-limited relay ff
14 does not operate, thereby preventing unnecessary step-out detection. This method can be easily configured if an external relay for the inverter Igi trip device shown at 17 in FIG. 3 is installed in each phase, and has been conventionally used. A relay is installed in each phase of a three-phase circuit, and the total
l Apart from the so-called distance relay system for each phase, which protects a three-phase power system with three relays, there is a switching distance relay system, which protects a three-phase system with one relay corresponding to one phase. There is something.

FIG. 5 is a block diagram of the switching type distance relay.

In Fig. 5, 18 is a back power source, 19 is a bus bar, 21 is a transmission line, 20 is a current transformer (hereinafter referred to as CT), 2
2 is an instrument transformer (hereinafter referred to as 吋). The three-phase voltages and currents are then introduced through PT and CT to fault phase detection relays installed in each phase shown at 13a, 13b, and 13c in the switching type distance relay 14, and the operation of these relays is Based on the results, a faulty phase is selected by a faulty phase selection circuit 23. That is, if the fault is a two-phase fault in the bc phase, after the faulty phase detection relays 13b and 13C operate, the output of the faulty phase selection circuit 23 causes the voltage/current switching circuit 24 to switch between the three-phase voltages and currents. Vbc (bc phase-to-phase voltage)
, and l bc (bc4n lightning current) are selected, and this voltage/current is introduced into the distance measuring circuit 25, which is configured to judge the distance to the accident point. Even in this case, the response to step-out is the same as for each phase-type distance relay, and a step-out lock circuit is required.

Figure 6 is a diagram showing the characteristics of each distance relay when a tax adjustment locking circuit is added to a protection device using switching type distance relays. In the figure, 14 is the characteristic of the switching type distance relay, and 1 and 2 are tax adjustment detection. This is the characteristic of the relay for. As mentioned above, in order to reliably lock out of synchronization at the time of tax adjustment, and on the other hand, to prevent the tax adjustment lock from being erroneously performed in the event of an actual accident, relay 1 must be connected to a specific phase among the three phases, and relay 2 must be If a total of three phases are installed in each of the three phases, it can be constructed in the same way as the case of each phase type distance relay.

[Problems with back m technology] In the above configuration, the relay for tripping the circuit breaker, which is the main function, was installed for only one phase out of three phases to simplify the configuration. For out-of-step detection, which is an additional function,
1 phase as relay 1, 3 phases as relay 2, total 4
This is not preferable, especially from an economical point of view, as it requires the installation of multiple relays.

[Objective of the Invention 1] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a protective relay equipment that minimizes the number of relay elements and is equipped with a tax adjustment lock function.

[Summary of the Invention] In the present invention, when a fault phase detection relay is operating for all three phases, or when the amount of electricity introduced into two relays installed for tax adjustment detection is connected to the corresponding phase. Only when only the failure phase detection relay of the same phase is operating, the out-of-step detection function is utilized by comparing the responses of the two relays.

[Embodiments of the Invention] Examples will be described below with reference to the drawings. FIG. 1 is a block diagram of one embodiment of a protective relay device according to the present invention. In FIG. 1, circuits having the same functions as those in FIG. 4 are designated by the same symbols. 1.2 in FIG. 1 is the output of a relay having the characteristics shown in 1.2 in FIG. Only one phase of each phase is installed so as to respond to the situation. Also the first
14 in the figure is the output of a switching type distance relay having the characteristics shown in 14 in Figure 6. The impedance up to the fault point is measured according to the type of fault phase in the protection system, and its dynamic V\ If it is within the range, it will produce an output and the disconnector will be configured in the same way. 10 is an AND circuit, and 13a, 13b and 13c are outputs of fault phase detection relays installed in each phase shown in FIG. The other configurations are the same as in FIG. 4.

First, let's take a closer look at what happens when an actual accident occurs. Here, relays 1 and 2 are installed in the AB phase, which is one representative phase of the three phases, and the accident is assumed to be a two-phase short circuit in the BC phase.

In this case, outputs are generated in the failed phase detection relays 13b and 13c, but since the a phase is a healthy phase, no output is generated in 13a, and the output of the AND circuit 10 remains "O".

Therefore, relays 1 and 2 installed in the ab phase are connected to the bc phase 2.
At the time of phase contact, the impedances shown at 11 points shown in Fig. 3 are observed, so even if relay 1 is activated and relay 2 is deactivated, no output is generated in AND circuit 3, and the time-limited relay for tax adjustment detection is activated. 4 is not activated.

Therefore, the flip-flop 5 is not set and its output is "0", and the output 1 of the NOT circuit 11 remains "1". Here, since the switching type distance relay is a bc phase two-phase short circuit accident, after the electrical quantities of Vl)C and lbc are applied and distance measurement is performed, if the result is within the set value, it will produce an output. , this passes through the AND circuit 12 and leads to tripping of the circuit breaker.

That is, as shown in Fig. 1, the step-out detection circuit is installed with relays 1 and 2 for detecting step-out only on one phase only, and on the condition that the fault phase detection relay is operating on all three phases. If activated, it would be possible to solve the problem of incorrectly detecting tax control and preventing the circuit breaker from tripping in the event of an actual accident.

Next, a response to a step-out will be explained. As mentioned above, the normal 12-tone is a three-phase balanced phenomenon, that is, a phenomenon similar to a three-phase short circuit, so the failure phase detection relays 13a, 13
b and 13c operate together, and the AND circuit 10 has an output "
1". As shown in FIG. 6, the impedance locus 16 at the time of step-out first enters the operating range of the relay 1 at point 12, but by the time it moves to point 13, more than the operating range of the time-limited relay 4 has elapsed. Therefore, the flip-flop 5 is set and a signal "1" is input to the NOT circuit 11, and the output of the NOT circuit 11 becomes "0". At this point, the switching type distance relay 14 for switching off the breaker is inoperative. After that, even if the step-out locus 16 moves to point 14 and enters the operating range of the circuit breaker exception relay (switchable distance relay) 14, the output of the negative circuit 11 will not flip. Due to the holding action of , rOJ continues, and breaker exception is prevented.

Furthermore, time passes and the out-of-sync trajectory is 85 points → P6 points → P
If you move to 7 points, the above P2 point → P3 point → P4
Although the response is completely opposite to the point, the output of the negative circuit 11 is rO
J continues, the breaker exception occurs and the circuit remains blocked.

That is, even in the event of a step-out, step-out detection can be reliably carried out, and an exception can be made to prevent the step-out.

FIG. 2 shows another embodiment of the invention.

In Fig. 2, the difference from Fig. 1 is that instead of using all three phases as a fault phase detection relay, only one relay is used.
and 2 is that only a fault phase detection relay of the same phase as the installed phase is used.

That is, relays 1 and 2 in FIG.
This shows an example where the relay is installed in the AB phase among the B, BC, and CA phases, and 13a and 13b of the A phase and B phase, which are the same phase, are used as the fault phase detection relay. There is.

First, we will explain how to respond in the event of an actual accident. Considering the bc phase two-phase short circuit as described above, 13b and 13C/fi operate as faulty phase detection relays. Here, since the a phase is a healthy phase, 13a does not operate, and therefore no output occurs in the AND circuit 10 in FIG. Therefore, the out-of-step detection circuit is not activated, and the subsequent response of the circuit is exactly the same as that at the time of the bc phase two-phase short circuit described above, and 12th adjustment will not be detected erroneously in the event of an actual accident.

Next, we will explain the response to the 1st tax adjustment. As mentioned above,
Since a normal step out is similar to a three-phase short circuit, the fault phase detection relays 13a and 13b operate together, and the AND circuit 10 produces an output of "1". Therefore, after this, by comparing the responses of relay 1 and relay 2, the circuit response is exactly the same as in the case of the step-out described above, and the breaker exception is reliably prevented after the step-out is detected.

Note that although Fig. 2 shows an example in which relays 1 and 2 are installed in the AB phase (inter-phase), if they are installed in the BC phase, two failure phase detection relays 13b and 13c are installed. If relays 1 and 2 are installed in the Ca phase, it may be combined with two fault phase detection relays 13b and 13C.

In short, it is sufficient to use a combination of fault phase detection relays of the same phase as the phases in which relays 1 and 2 are installed.

In addition, in Figures 1 and 2, the fault phase detection relays are as follows:
The figure shows an overcurrent relay that introduces only current, but if the relay has a fault phase detection function, it can handle voltage or voltage/voltage.
It is clear that the present invention can be applied to relays driven by both electric current and electric current.

[Efficacy of invention! ! ] As explained above, according to the present invention, a switching type distance relay and two relays with different operating ranges installed in only one of the three phases of the system can reliably detect and shut off synchronization during tax adjustment. Therefore, it is possible to provide a protective relay device that prevents erroneous step-out detection in the event of an actual accident.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the protection relay device according to the present invention for detecting step-out and excluding the breaker, Fig. 2 is a diagram showing another embodiment of the present invention, and Fig. 3 explains the principle of detecting step-out. R-X diagram for,
FIG. 4 is a block diagram of a conventional step-out detection and breaker exception circuit, FIG. 5 is a diagram for explaining the configuration of a beam 8 type distance relay, and FIG. 6 is a distance relay constituting an embodiment of the present invention. Electric;
FIG. 2 is an RX diagram showing the characteristics of S. 1...Output of offset motor relay 2...Output of motor relay 3.8.10.12...AND circuit 4.9...Time limit @# electric appliance 5...Flip-flop 6.7. 11...Negation circuits 13a, 13b, 13c...Failure phase detection relay 1
4...Switchable distance relay 15...Relay maximum @maro angle 1G...Impedance locus at step-out 17...Moh characteristic relay output 18...Back power supply 19...Bus bar 20...
Instrument current transformer 21...Power transmission line 22...Instrument transformer 23...Failure phase selection circuit 24...Voltage/power cutoff 8 circuit 25...Distance measuring circuit

Claims (1)

[Claims] A first relay installed in each phase to input the voltage and current of the three-phase power system and detect the fault phase in the event of a system fault;
a second relay that responds to the voltage and current of any phase of the three phases of the power system; and a second relay that responds to the voltage and current of the same phase as the second relay, and a wider operating range than the second relay; and a third relay having a
and a protective relay device that detects an out-of-step in the power system by comparing the responses of the second relay and the third relay only when a relay of the same phase as the third relay is operating. .