JPS5930015B2 - Phase comparison transport protection relay system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protection system in the event of multiple faults spanning both lines of a phase comparison relay device.

BACKGROUND OF THE INVENTION As protective relay devices for important power transmission lines such as so-called main power transmission lines in power systems, high-speed operation, high-reliability transport protection relay devices with excellent protection performance are generally employed.

In particular, ultra-high-voltage and ultra-ultra-high voltage power transmission lines are equipped with phase-comparison transport protection relay devices for each phase that can apply a multi-phase reclosing method that selectively cuts off only the failed phase and recloses the circuit at high speed.

This phase comparison carrier protection relay device correctly responds to and eliminates accidents between the terminals of the line in which it is installed, and conventional devices were able to respond correctly to various accidents within their protection responsibilities.

However, it was newly discovered that the system was malfunctioning due to an accident on an adjacent line, which was not originally under its protection responsibilities.

To explain this phenomenon, this is a parallel two-circuit power transmission line with a phase comparison conveyance protection relay device installed at each terminal.
This became a problem when accidents occurred on both lines at the same time.

At this time, the phase comparison relay device operates, and all four terminals of the circuit breaker are disconnected from the fault phase only, the fault is removed from the system, and after the reclosing no-voltage period, the tripped circuit breaker is closed again. .

At this time, if Line 1 is in an arcing accident and Line 2 is in a permanent accident, Line 2 will continue to have an accident due to re-closing, so the phase comparison relay will detect this and issue an output again. The circuit breakers at both terminals are then tripped for all three phases, regardless of the fault phase, removing the fault from the system.

However, Line 1 was cut off by the phase comparison relay due to an arcing accident, and the accident disappeared and the circuit was successfully reclosed.
You should be able to continue driving safely.

However, as will be explained in detail later, conventionally, a continuous trip permission signal (hereinafter referred to as continuous F2 signal) is sent to the other end during the breaker open period, so the phase comparison relay device has not yet recovered when the breaker is reclosed. I haven't.

Then, because the voltage has dropped due to a permanent fault on the adjacent line, the undervoltage relay is also in operation, and the re-closing failure detection condition for line 1 is met, and at the same time as line 1 is reclosed, it is cut off again like line 2. become.

In other words, originally two-line operation becomes one-line operation, but the grid connection between both terminals is maintained and power supply is supposed to continue, but an accident occurs on both lines at the same time, causing a one-line arc accident, In the case of a permanent single-line fault, as long as the conventional phase comparison carrier protection relay device is installed, both circuits will be cut off and the system will be unnecessarily divided, resulting in a significant drop in system reliability.

The present invention was made in view of these newly discovered problems, and an object of the present invention is to solve the problem by allowing the phase comparison relay to be restored more quickly than the circuit breaker has to be turned on again.

Specifically, the carrier from the power supply terminal is controlled to the F1 signal,
The above time relationship is satisfied by determining the time corresponding to the release of the circuit breaker.

Further, as a result of this, the continuous F2 signal becomes shorter, so when two-phase interconnection is confirmed from the F2 signal, this is stored until the breaker is turned on again.

An embodiment of the present invention will be described below.Prior to that, the operating principle of the phase comparison transport protection relay system for each phase will be explained with reference to FIGS. 1 and 2, and the conventional continuous F2 signal control circuit with reference to FIG. I will explain.

FIG. 1 shows the power system in which the phase comparison relay 7 is installed.

Installed at electrical station B.

Items common to both electrical stations are designated by the same reference numerals.

Reference numeral 1 indicates a busbar, and reference numeral 2 indicates a generator behind the power station. When a fault occurs on the power transmission line, the fault current is supplied from this generator.

The busbars 1 of electric stations A and B are interconnected by a power transmission line 5 via a circuit breaker 4, respectively.

When an accident occurs on the power transmission line 5, the relay side current 6 proportional to the fault current flowing through the power transmission line 5 is guided by the current transformer 3 installed at both electric stations to the phase comparison relay 7, and the output circuit 11 of 7 The circuit breaker 4 is opened.

The current 6 guided to the phase comparison relay 7 is converted from a sinusoidal alternating current into a rectangular wave by a rectangular wave shaping circuit 8 inside the phase comparison relay.

The relay side currents 6A and 6B detected at both electric stations have the same polarity when a passing current occurs in the event of an external fault as shown in FIG. 2a.

In the phase comparison relay that is treated as the power supply end of electric station A, the rectangular wave made of a positive half wave that exceeds level LH becomes a trip-permissible phase signal (hereinafter referred to as F2 signal), and the other sections are tripped. This becomes a lock phase signal (hereinafter referred to as F1 signal).

In addition, in the phase comparison relay that is treated as a variable power supply terminal at electric station B, the rectangular wave created by the current on the side that includes zero at level L1 becomes the F2 signal, contrary to the power supply terminal, and the other sections are This becomes the F1 signal.

The phase signal generated by the rectangular wave shaping circuit 8 is guided to the matching circuit 9 (actually, it passes through a circuit that compensates for the transmission delay time until the phase signal transmitted from the other end reaches the matching circuit 9 at the other end). is omitted here for the sake of brevity), and is simultaneously transmitted to the transmitter 13 of the information transmission device 12, and generally further transmitted to the receiver 14 of the other party's information transmission device 12 via the microwave line 15. Ru.

On the other hand, in the same way, the other end phase signal sent from the transmitter 13 of the other end information transmission device 12 through the microwave line 15 passes through the receiver 14 of the information transmission device 12 at the other end, and then passes through the phase comparison relay 7. It is introduced into another input of the matching circuit 9.

In the matching circuit 9, an AND signal of the F2 signals at both ends is created,
If this magnitude is measured by the next integrating circuit 10 and is large enough to be determined as an internal accident to be protected (generally 60°) or more, the output circuit 11 issues a command to trip the circuit breaker 4.

Although only one set of phase comparison relays is shown in FIG. 1, in reality, they are installed for each of the A, B-, and C phases, and the above-mentioned operation is performed independently for each set.

Next, referring to FIG. 2, the response of the device shown in FIG. 1 to a system accident will be explained.

Components in FIG. 2 that are the same as those in FIG. 1 are designated by the same reference numerals.

Figure 2a shows the response to an accident outside the protected area, and as shown, the accident point F is outside the electrical station B.

Therefore, the current on the relay side of the transformer 3 is A terminal 6A and B terminal 6B.
Then, both the size and the phase will be the same.

The A terminal current, which is treated as the power supply terminal, is converted into a rectangular wave by the slice level LH in the rectangular wave shaping circuit 8 as shown in 8A, and then F2
The other sections are F1 signals.

The B-terminal current, which is treated as a variable power supply terminal, is converted into a rectangular wave by the slice level LL in the rectangular wave shaping circuit 8, and is converted into an F2 signal as shown in 8B, contrary to the electrical station A, which is treated as a power supply terminal, and the other section is an F1 signal. become.

The matching circuit 9 ANDs the F2 signals of 8A and 8B, but as shown in 9(A, B), there is no AND output of 9, and therefore the 10 integrating circuit and the 11 output circuit have 10(A, 8B), respectively. As shown in B) and 11 (A, B), there is no signal at all, so no breaker trip signal is issued.

Here, the slice level LH at the power supply end and the slice level LL at the variable power supply end, :! It is a well-known fact that : is configured so that LH>LL so that the F2 signals at both ends do not overlap due to an external accident.

Figure 2 shows the case of an internal accident when power is supplied at both ends, and as shown, there is an accident point F on the power transmission line 5 connecting electric station A and electric station B.

Due to an internal accident in the section, contrary to Figure 2a, the currents on the relay side of transformer 3 A terminal 6A and B terminal 6B are almost in opposite phase 8
As shown in A and 8B, phase signals are generated at each terminal station, and the F1 signal and F2 signal are generated, so the coincidence circuit 9 at both ends
A coincident output as shown appears at A and B, and when this is measured (integrated) by the integrating circuit 10, it reaches the slice level SL of the integrating circuit as shown at 10 (A, B), and the output circuit 11 ( Outputs are output from A and B), and this signal opens the circuit breaker and eliminates accident F.

In Figure 2 C, the accident point is inside the protected area as in Figure 2, but unlike in Figure 2, there is no power source behind electric station B at the variable power source end (there is no generator 2), so B This is the case where no fault current is supplied from the end.

Therefore, 6A and 8A are exactly the same as in figure b.

However, as shown in 6B, the current at the B end is not completely heated, so it is always below the LL level, and as shown in 8B, it is F over the entire section.
2, that is, it becomes a phase signal that allows continuous tripping.

Therefore, the F2 signal of 8A appears as it is in the double-end coincidence circuit 9 (A, B), and the breaker trip signal is clearly generated from 10 (A, B) and 11 (A, B).

In other words, if it is treated as a variable power supply terminal, the breaker can be tripped even if no fault current flows.

Using Figure 3, Figure 4, Figure 6, and Figure 1, in the case of the simultaneous accident on both circuits mentioned earlier, with an arcing accident on Line 1 and a permanent accident on Line 2, the circuit was successfully reclosed and stable operation continued. 1 that should be possible
We will explain in detail the defects that cause the line to be cut off again due to permanent accidents.

Of the components shown in these figures, those that are the same as those in FIG. 1 are denoted by the same reference numerals, and it is clearly stated here that this concept is followed in the drawings that appear below.

First of all, Figure 3a shows the power system in which the phase comparison relay is installed, similar to Figure 1, but unlike Figure 1, electric station A and electric station B are connected to a two-circuit transmission line, that is, one line 5. -1L is connected to the 2-blade line 5-2L.

It is assumed that the accident point on Line 1 is FA, and an arc accident has occurred.

Therefore, if the circuit breakers 4 at both ends of 5-1L are opened, the fault FA will disappear, so if the circuit breakers 4 at both ends of 5-1L are turned on again after a no-voltage period, the system should return to its original stable state. be.

It is assumed that the accident point on Line 2 is FP and a permanent accident has occurred.

Therefore, even if the circuit breaker 4 at both ends of 5-2L is opened and then reclosed, the accident continues and the circuit is shut off again, and the circuit breaker 4 at both ends of 5-2L remains open.

Figure 3 shows the concept of a breaker circuit, where 7-a is a normally open contact that closes when the phase comparison relay operates, and 16 is a normally open contact of an undervoltage relay for fault detection, which is used to detect faults in the system. , it operates and closes when undervoltage is detected.

Therefore, if an accident occurs inside the protected area in the system, contact 7
- Since a and 16 are closed, a cutoff command is generated from the operation bus P to the cutoff coil of a breaker (not shown), and the breaker is opened.

FIG. 4 shows a transfer control circuit for sending Fl and F2 signals formed from the currents at each end to the other end.

11 is a contact of a coil that is energized by a pallet switch when the breaker contact is opened, and is closed when the breaker is opened.

18-1 is a contact of a coil (described later) which is energized by the excitation signal of the closing coil for restarting the circuit breaker, and is opened when the closing coil is excited.

, OR represents an OR gate, and PT represents a power supply for a signal.

In this circuit, when the breaker is closed, the contact 17 is open, and when there is a signal from the rectangular wave shaping circuit 8 of the phase comparison relay 7 to the transmitter 13 of the information transmission device 12, the F2 signal is transmitted to the transmitter 13. When there is no signal to the other end, the F1 signal is sent to the other end.

Then, when a cutoff command is issued and the breaker opens, contact 17
Since the circuit is closed, a signal is continuously supplied to the transmitter 13 from the power supply PT, so a continuous F2 signal is transmitted to the other end, and this continues until the breaker is turned on again.

Here, the reason why the continuous F2 signal is forcibly generated when the circuit breaker is open is explained. One of the reasons is to facilitate the circuit breaker, especially at the end of the variable power supply.

In other words, a) if the breaker at the power end side opens in advance for some reason when an accident occurs, or b) an internal accident occurs when only the breaker at the power end side is opened and the line is being charged from the variable power end side. Considering that, the carrier signal sent by the phase comparison relay at the power supply end is a continuous F1 (trip prevention) signal because the current detected by it is zero due to the opening of the breaker, and the carrier signal sent by the phase comparison relay at the power supply end is a continuous F1 (trip prevention) signal. Regardless of the situation, the breaker array cannot be removed at the variable power source end.

The second reason is that one of the conditions for allowing reclosing is that there is a total of two or more phases of interconnection between two circuits.

” can be given.

This is to confirm that the power supplies at both ends of a two-line power transmission line are synchronized. For example, in the first line, the human phase and B phase are open due to an accident, and in the second line, the B phase and C phase are open. Assuming that the phases are open, two phases A and C are interconnected between the two poles.

On the other hand, if the A phase and B phase of both the first and second lines are open, only the C phase is interconnected.

In the former case, the remaining one phase is also considered to be in a synchronized state, but in the latter case, where only one of the three phases is interconnected, synchronization cannot be guaranteed.

Needless to say, reclosing without confirming synchronization is not allowed, and the easiest and most reliable way to confirm two-phase interconnection at the other terminal at the own terminal is to detect the continuous F2 signal when the breaker is opened. It depends.

In order to determine whether the accident continues after the breaker is turned on again, contact 18-1 is opened at the same time as the closing coil is energized to cancel the continuous F2 signal.

Figure 6 shows the re-closing circuit of the breaker, and Figure 1 shows the signal waveforms of various parts after the occurrence of an accident until the breaker is re-closed (I is on the variable power supply end side, ■ is on the power supply end side) It shows.

Using FIG. 7 to explain the functions of FIGS. 3b and 4 until the accident is removed, the accident occurs at the time t.

In the previous state, the response was similar to that in the case of an external accident as shown in FIG.

Due to the occurrence of an accident, the carrier signals sent from both ends become almost in the same phase, and the F2 signals match.

As a result, before t, both the undervoltage relay 16 and the phase comparison relay 7 are in a non-operating state, and when an internal fault occurs, they are activated to open the circuit breaker 4 at time t1.

However, the time when the F2 signal matches the delayed phase signal from the own end and the phase signal from the opposite end, this state continues for a predetermined time, and the phase comparison relay 1 enters the operating state is t.

Set to 1. The contact 17 in FIG. 4 is closed when the circuit breaker 4 is opened, and thereafter the carrier signal 15 transmitted from its own end becomes a continuous F2 signal as shown by the solid line.

The operation up to this point is exactly the same at the power supply terminal and the variable power supply terminal.

By opening this breaker, the voltage is restored and the undervoltage relay 1
6 is inoperative at either terminal, but when looking at phase comparison relay 7, it is inoperable at the power supply end (a continuous F2 signal is obtained from the other end, but since the current is zero at the own end, it is at a level equivalent to a continuous F1 signal). It's a signal.

), the variable power source terminal operates (a continuous F2 signal is obtained from the other end, and since the current is zero at the own end, the signal is at a level equivalent to the continuous F2 signal).

) continues. FIG. 1I shows the variable power supply end, and it is the variable power supply end that will malfunction in the event of an accident that spans both lines.

The reclosing circuit shown in FIG. 6 starts operating from this accident removal time t1.

In FIG. 6, 97 is a contact that closes when the circuit breaker 4 is opened, thereby exciting the auxiliary relay 34.

34-1 is the contact point of 34. Reference numeral 26 is a contact that is closed only when re-closing is performed. For example, during single-end line charging operation in which one breaker is opened and the line is charged only from one end, re-closing is not performed, so contact 26 is closed. It remains as it was.

23 is a timer for measuring no-voltage time.

Timer 23 closes contact 2 at time t2 after the no-voltage time has elapsed.
3-1 is closed.

18,20゜21 is the auxiliary relay coil, 201.20
-2 is the normally open contact of the coil 20, 21-1, 21-2 is the normally open contact of the coil 21, 22 is the normally open contact of the auxiliary relay that is energized when the breaker is closed again, and 23-1 is the normally open contact of the auxiliary relay The normally open contact 24-1 of the timer 23 that counts the no-voltage time from the removal time t1 is connected to the re-closing condition (for example, 2 circuits total for 2 circuits).
Auxiliary relay 24 that operates if interconnection is established
The normally open contact 25 (described later with reference to FIG. 9) is the normally closed contact of the auxiliary relay that is energized in the event of a system fault.

Further, 19 is a closing coil of the breaker, 96 is a pneumatic contact that closes when the operating air pressure of the breaker is normal, and PN is a DC operating bus bar.

In FIG. 6, the circuit section that determines the operation of contact 23-1 (consisting of auxiliary relays 34, 23, etc.) measures the no-voltage time from the time the circuit breaker is tripped. The time at which the breaker tripping command signal is issued may be used as a reference.

The auxiliary relay 27 is added according to the present invention, and its function will be described later.

The operation of FIG. 6 will be explained with reference to FIG. 7 as follows.

Contact 23-1 closes at time t2 when the voltage-free time has elapsed from fault removal time t1.

At this time, if there is no accident in the system and the reclosing conditions are satisfied,
Since the contacts 24-1 and 25 are both closed, the auxiliary relay 20 is energized and self-maintained by the contact 20-1, and the auxiliary relay 21 is energized by the contact 20-2.

The auxiliary relay 21 is self-held by the contact 21-2, and at the same time, the closing coil 19 is closed by the contact 21-1 at time t2□.
is excited, and if the air pressure is normal, the contact 96 is closed, so the circuit breaker is closed at time t4.

Contact 21-1 also excites auxiliary relay 18 in parallel with closing coil 19 at time 121, and opens normally open contact 18-1 (FIG. 4) of auxiliary relay 18 at time t3.

At the time of this opening, the power side side comparison relay 7 is not outputting (the current at its own end is zero until time t4 when the circuit breaker 4 is turned on again, and corresponds to the continuous F1 signal ++ 0 II
Output the level.

) Therefore, the carrier transmitted from the power supply end immediately becomes a continuous F1 signal and is received by the variable power supply end at time t31 after the transmission delay time Td.

Upon reception of this F1 signal, the phase comparison relay 7 at the variable power supply end goes into the recovery state and becomes completely inoperable at t.

Regarding the carrier sent out from the variable power supply end, the contact 18-1 (
The F2 signal is continuous regardless of whether the circuit breaker is opened (FIG. 4) (when the current is zero when the circuit breaker is opened, the variable power supply terminal outputs a 1'' level corresponding to the F2 signal).

). After time t4, it is determined by the input current.

In the above description of FIG. 1, it is assumed that all other operations except for the operation of the phase comparison relay 7 are substantially the same at both terminals, and that the sequences at both terminals proceed substantially simultaneously.

As is clear from this figure, on the variable power supply end side (Fig. 7 1), the phase comparison relay's recovery time 1. (T1 hours after time t2 after the no-voltage time has elapsed) is breaker closing time 14 (from time t2 to T).

hours later).

By the way, the operating time of the auxiliary relays 18 and 20.21 is approximately 15 (msec) each, the operating time of the closing coil 19 is 30 to 40 (msec), and the transmission delay time is approximately 5 (msec).
msec), the recovery time of phase comparison relay 7 is approximately 20
(msec), To and T1 are each 60 to 70
GT1sec), about 70 (msec).

This did not pose any problem in the conventional phase comparison relay device described above.

In other words, in the first case, if there is no internal fault when the breaker is turned on at time t4, the undervoltage relay in the tripping circuit shown in Figure 3 is inoperable and contact 16 is open. Because there is, it will not be cut off again.

In the second case, if there is an internal fault at time t4, a tripping signal can be instantaneously provided by the operation of the undervoltage relay, which is rather convenient for high-speed operation.

As a third case, when an external accident occurs at time t4, it is possible that the circuit will be erroneously cut off and the re-closing will fail, but this is almost impossible in practice.

That is, in FIG. 6, the excitation of the closing coil 19 of the breaker is caused by the contact 25 without any accident (the contact 25 is that of an undervoltage relay).

) has been confirmed, and it is impossible as an accident phenomenon that there is no accident at time t2 and an external accident occurs by t4 immediately thereafter.

In this way, follow-up accidents like the third case (two or more accidents occurring consecutively) are also limited to a short period of time based on the time of the second occurrence. Since such phenomena are completely absent, it was considered that the conventional phase comparison relay device is completely reliable in terms of reclosing operation.

However, this is the first time that it has been revealed that a third case like this occurs.

This is the single-blade wire erroneous disconnection during the single-blade arc accident and permanent fault of Line 2 mentioned above, and the line 1 re-closing failure occurred due to the voltage drop due to the permanent fault occurring when the two-blade wire was reclosed. Become.

Such a case is virtually unprecedented, and it would have been impossible to predict that there would be a case where a problem would surface due to reclosing the circuit.

The present invention aims to take measures against this problem, and the seventh
As is clear from the time diagram in the figure, in the conventional method, T1>To
Therefore, the arc fault line will be shut off again.

From the above explanation, it would be better to restore the phase comparison relay, which operates at the LL level and is treated as a variable power supply terminal, a little earlier.

To this end, the breaker on the phase comparison relay side, which operates at the LH level and is treated as a power supply end, should be turned on early.

For example, if the no-voltage time on the power supply end is set shorter than that on the variable power supply end, the phase comparison relay 7 on the variable power supply end can be reset before the breaker on the variable power supply end is turned on. good.

However, in recent years, phase comparison relays installed in ultra-high voltage systems or ultra-super high voltage systems often have two series as shown in Figure 5, and in series A, electric station A is treated as the power source end, and electric station B is treated as the variable power source. In the B series, unlike the A series, electric station A is treated as the variable power source end, and electric station B is treated as the power source end, so phase comparison relays that operate at the LL level are installed at both electric stations. Therefore, it is no longer possible to take measures by making a difference in the no-voltage time.

Therefore, one embodiment according to the present invention is shown in FIGS. 8 and 9, and its effectiveness will be explained.

FIG. 8 shows a transport control circuit according to the present invention.

The difference between this Fig. 8 and the conventional example shown in Fig. 4 is that the contact 1
7 and 18-1 as a continuous F2 signal,
This point is determined by contact points 17 and 27.

This contact 27 is a normally closed contact of the time-limited auxiliary relay 27 shown in FIG. 6, and is driven in response to tripping of the breaker and opens at time t11 approximately 100 (msec) later.

Therefore, both contacts 17 and 27 close to produce a continuous F2 signal, which is approximately 100 m
00 (between.

Generally, the no-voltage time is 300 to 400 (msec), so the F2 signal is continuous for a sufficiently short time compared to the conventional method.

By the way, if we look at the operating status of each circuit before time t1□, this is the same as before, so we will omit the explanation, but if we consider what happens when contact 27 opens at time tll, at the power supply terminal The sending carrier is a continuous F1 signal as shown by the dotted line (one input of the OR circuit OR in FIG. It inputs zero current and outputs +10 jj.

). This continuous F1 signal is received at the variable power supply end and resets its phase comparison relay 7.

After t1, the time it takes for the phase comparison relay 7 at the variable power supply end to actually recover is over 100 msec, and at time t
By the time the circuit breaker was turned on again in step 4, it had completely recovered.

Therefore, even in the case of an arcing accident on the own line or a permanent accident on the adjacent line as shown in FIG. 3, there will be no possibility of erroneous re-closing failure.

In addition, considering the operation of the variable power supply terminal after t1□ in FIG. The continuous F2 signal continues to be output regardless of the current state.

The phase comparison relay 7 at the power supply end receives the continuous F2 signal, but is inactive because it generates the continuous F1 signal at its own end.

The circuit shown in FIG. 6 will be properly restored after the circuit breaker is turned on again, and will return to the state before the accident occurred.

According to the circuit of the present invention, as mentioned above, the continuous F2 signal is used to detect phase interruption at the other end and detect the re-closing condition, for example, two-phase interconnection in two lines in total, but since the continuous F2 signal is only transmitted for a short period of time, If a cut-off phase is detected during this temporary time period, it becomes necessary to maintain that condition.

However, this can be realized very easily as shown in FIG.

Figure 9 shows a circuit provided for each phase to detect that the carrier from the other end is a continuous F2 signal. The normally closed contact of the auxiliary relay 21 (see FIG. 6) is operated, and 30 is the normally closed contact of the auxiliary relay that operates at final cutoff (cutoff due to failure of reclosing).

31 is a normally open contact of an auxiliary relay (not shown) that operates when the F2 signal is determined to be a continuous F2 signal when the length is, for example, 20 msec or more, and 28-a is a self-holding contact of the auxiliary relay 28. It is.

By this circuit, the continuous F2 signal between t1 and tit in FIG. 7 is stored until reclosure is performed and final cutoff is performed.

FIG. 9a shows that this circuit is used to confirm that there is interconnection of two or more phases in total for two lines.

In FIG. 9a, 211, 28-2, and 28-3 are the A phase, B phase, C Normally closed contact of phase, 28'-1゜28'-2, 28'-
3' (dash) indicates the A, B, and C phases of the auxiliary relay shown in the figure, which similarly operates by detecting the continuous F2 signal from the other end of the adjacent line. It is a normally closed contact.

29-1゜29-2.29-3 is a normally closed contact of an auxiliary relay for each phase, which operates simultaneously with a cutoff command at its own line end and is self-maintained until reinsertion or final cutoff, although 29-3 is not shown. -1, 29'-2, and 2g-3 similarly perform the same operation at the adjacent line's own end.

According to this circuit, a continuous F2 signal cannot be obtained before the accident occurs, the auxiliary relay 28 is inoperative, and the contact 28°2
8' is closed.

Contacts 29 and 29' were also closed before the accident occurred.

As a result, all the contacts in FIG. 9a are closed and the auxiliary relay 24 is in an energized state, closing the contact 24-1 in FIG. 6.

These contacts are opened by disconnecting the breaker array as described above, and are maintained in the open state until final shutoff occurs following completion of re-closing.

In this circuit, the two sets of series contacts with a dash or the two sets of series contacts without a dash represent the open/closed state of that phase of the line, for example contacts 29'-2,
The fact that the 3σ-2 series circuit is open means that the breaker of the adjacent line B phase is open.

The circuit composed of the six sets of contacts on the rightmost side in FIG.

” holds true and energizes the auxiliary relay 24.

Similarly, the six contact groups on the center and left side are [own line B
The phases are interconnected, and at least one of the adjacent lines A phase or C phase is interconnected.

In other words, the circled line A phase is interconnected, and at least one of the adjacent line B phase or C phase is interconnected.

This is to confirm that

It has been confirmed that each of these 6 contact groups has 2-phase interconnection for a total of 2 circuits, and according to the overall configuration shown in Figure 9a, 2
This means that it will be detected that there is interconnection of two or more phases in total lines.

Output contact 24-1 of auxiliary relay 24 is used in the reclosing circuit of FIG. 6 to prevent breaker reclosing when two-phase interconnection is not confirmed.

It should be noted that FIG. 9 only shows one phase, and it goes without saying that all the other phases are also self-supported independently.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the principle of the phase comparison transport protection relay system, Figure 2
Figure 3 is a diagram explaining the response under various conditions of the same system, Figure 3 is a diagram explaining problems in the conventional system, Figure 4 is a conveyance control circuit diagram, Figure 5 is a diagram of a two-sequence phase comparison conveyance protection relay system, 6
FIG. 7 is a diagram of a conventional transport control circuit, FIG. 7 is a time chart showing its operation, and FIGS. 8 and 9 are circuit diagrams of a phase comparison transport protection system according to the present invention. 1... Bus bar, 2... Generator, 3...
... Current transformer, 4... Breaker, 5...
...Transmission line, 6...Relay input current, 7...
... Phase comparison relay, 8 ... Rectangular wave shaping circuit, 9 ... Matching circuit, 10 ... Integrating circuit, 11 ... Output circuit, 12 ...... Information transmission device, 13... Transmitter, 14... Receiver, 15... Microwave line, 11...
. . . A contact that closes between circuit breakers, 27 . . . A contact that closes after a predetermined time after starting the re-closing circuit.

Claims (1)

[Claims] Applied to a power transmission line with a 12-line configuration, the current of the transmission line is detected for each phase at each terminal of the transmission line, and when the current passing through the transmission line is viewed as having the same polarity at each terminal, phase comparison is performed as if it were treated as a power supply terminal. The relay sends a phase signal to the other end that allows tripping during a period when the current is above a predetermined current level and does not include zero current, and prohibits tripping during other periods, and the phase comparison relay, which is treated as a variable power supply end, and sends a phase signal to the other end that allows tripping during a period including zero current and prohibits tripping during other periods, and sends a continuous phase signal that allows tripping to the other end at the open terminal of the breaker, At each terminal, the phase comparison relay at its own end determines whether the phase signal at its own end matches the trip permissible portion of the phase signal at the other end and outputs it, when it detects a drop in the line voltage at its own end and detects an undervoltage. The fact that the relay is also outputting opens the circuit breaker at its own end, and when the transmission line is reclosed, it sends a message from the other end that at least two phases of interconnection are maintained between the two transmission lines. In the phase comparison relay method, which uses continuous trip permissible phase signals that are received by the user to confirm the breaker reclosing circuit, the phase comparison relay, which is treated as a power source end, is used to confirm that a predetermined period of time has elapsed after the breaker is opened. Then, the transmission of the continuous phase signal that is trip-permissible due to the opening of the breaker is stopped, and the first point in time when the phase signal is received at the variable power supply terminal and the phase comparison relay is restored is the variable power supply terminal. At least at the variable power supply end, the two-phase interconnection is confirmed and re-confirmed from the received continuous trip permission signal. The circuit breaker is closed or the circuit breaker is closed.7
A phase comparison transfer protection relay system characterized by storing signals up to power failure and using the stored signals as conditions for two-phase interconnection.