JPS5937650B2 - Phase break detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new banknote detection circuit for detecting a reclosing condition of a phase comparison transport protection relay device.

As a protective relay device for an important power transmission line such as the so-called main power transmission line of an electric power system, a transport protection relay device with excellent protection performance, high speed operation, and high reliability is generally employed.

In particular, for ultra-high-voltage and ultra-ultra-high-voltage power transmission lines, a multiphase reclosing method can be applied that selectively cuts off only the failed phase, detects two-phase interconnection in two circuits, and recloses at high speed. A protective relay device will be installed.

By the way, in order to perform polyphase reclosing, it is necessary to detect two remaining phases in total of two circuits as a reclosing condition.

In addition, depending on the system, in consideration of the transient effect on the generator during reclosing, a method is adopted in which three phases remaining in two circuits in total are detected and multiphase reclosing is performed based on this condition.
The present invention will be described using a more general polyphase reclosing method in which two remaining phases are detected based on a total of two circuits.

For two-phase interconnection detection, which is the only reclosing condition for the high-speed multiphase reclosing method, it is necessary to accurately grasp the cut-off state of the own end and the cut-off state of the opposite end.

However, detection of a new faulty note at the own end can be easily achieved by detecting the trip command of each phase at the own end, but detection of a new faulty note at the other end is somewhat difficult. Regarding the terminal station, it will be explained in detail later, but in short, we focused on the fact that the terminal station that is treated as the power supply terminal sends a continuous trip permission signal when the power supply terminal is cut off, and the variable power supply terminal receives this signal to shut off the power supply terminal. phase can be detected.

However, this method cannot be used at terminal stations that are treated as power supply terminals, so a highly sensitive overcurrent relay is installed on each phase, and the phase on which this overcurrent relay is activated is interconnected, including the other end. A phase that is in operation or a phase that is not operating is determined to be a phase in which either both ends, the own end, or the opposite end are cut off.

In this way, with the conventional method of detecting phase cutoff using an overcurrent relay at the power supply end, if the charging current of the power transmission line increases due to the length of the power transmission line, only the other end is cut off. In such a case, the overcurrent relay will operate with a charging current, mistakenly determining that grid connection is present, and in severe cases, causing extremely serious problems such as connecting different systems and damaging the generator. There is a risk that it will cause

Next, this will be explained using the drawings.

First, the principle of operation of the phase comparison transfer protection relay power system will be explained with reference to FIGS. 1 and 2, and the conventional new banknote detection circuit will be explained with reference to FIGS. 3 to 5.

FIG. 1 shows a power system in which a phase comparison relay 1 is installed, and the phase comparison relay is installed at an A electric station and a Bt electric station.

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

1 is a busbar, and 2 is a combination of generators behind the electric station. When an accident occurs on a power transmission line or the like, 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.

Current 1 converted to relay side current by current transformer 3
6 is inputted to the phase comparison relay 7 via the overcurrent relay 6 for detecting new bills at the electrical station A, which is treated as a power supply end.

In the electric station B, which is treated as a variable power supply end, the current of the system is directly input from the transformer 3 to the phase comparison relay 7.

The current guided to the phase comparison relay γ is converted from a sine wave (alternating current) into a rectangular wave by a rectangular wave shaping circuit 8 inside the phase comparison relay.

At electrical station A, which is treated as a power supply terminal, a square wave made of a positive half wave becomes a trip permission signal (hereinafter referred to as F2 signal), and the other section is a trip lock signal (hereinafter referred to as F1 signal).
becomes.

Further, at the variable power supply end, the negative half-wave rectangular wave generated by the rectangular wave shaping circuit 8 becomes the F2 signal, contrary to the power supply end, and the other section becomes the F signal.

The square wave created in step 8 is the coincidence circuit 9 of the self-end phase comparison relay.
At the same time, the information is transmitted to the transmitter 13 of the information transmission device 12, and further generally transmitted to the receiver 14 of the other end information transmission device 12 via the microwave line 15.

On the other hand, similarly, the other end rectangular wave sent through the microwave line 15 by the transmitter 13 of the other end information transmission device 12 passes through the receiver 14 of the information transmission device 12 at the other end, and then passes through the phase comparison relay 7. is introduced into another input of the matching circuit 9.

The matching circuit 9 generates an F2 signal at both ends, and if this magnitude is measured by the next integrating circuit 10 and is large enough to determine an internal fault (generally 60°) or more, the output circuit 11 triggers the circuit breaker 4. A removal command will be issued.

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

Furthermore, although the power transmission line 5 only shows one circuit or one circuit in Figure 1, it usually has a two-circuit configuration, so there are six phase comparison relays in one electrical station, two circuits for each phase, for a total of six. will be installed.

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.

FIG. 2a shows the response to an accident outside the protected area, and therefore the relay side current 16 of the transformer 3 has the same magnitude and phase at the A end (16A) and the B end (16B).

The A terminal current treated as the power supply terminal is converted into a rectangular wave by the slice level LH as shown at 8A in the rectangular wave shaping circuit, and becomes the F2 signal in the positive half wave and the F1 signal in the other sections.

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 other than that it is converted into a F2 signal with a negative half wave as shown in 8B, contrary to the A electric station, which is treated as a power supply terminal. The section becomes F1 signal.

The coincidence circuit 9 ANDs the F2 signals of 8A and 8B, but as shown in 9 (A, B), there is no AND output of the AND circuit 9 in the event of an external fault, and therefore the integrator circuit 10 and the output circuit 11 each have an AND output. 10 (A, B), 11 (A,
As shown in B), there is no signal at all, so no breaker row removal signal is issued.

It is a well-known fact that the slice level LH at the power source end and the slice level LL at the variable power source end are configured such 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 current on the relay side of transformer 3 is almost in opposite phase at terminal A (16A) and terminal B (16B), and as shown in 8A and 8B, the current on the relay side of transformer 3 is almost in opposite phase. Since a rectangular wave is created and the F1 signal and F2 signal are generated, a coincidence output as shown appears in the coincidence circuits (9 (A, B)) at both ends, and this is measured (integrated) by the integration circuit 10. Ba,
As shown in 10 (A, B), the slice level SL of the integrating circuit is reached, and an output is generated from the output circuit 11 (A, B).
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 the B end This is the case when no fault current is supplied from the

Therefore, 16A and 8A are exactly the same as shown in FIG.

However, the B terminal current does not have any total heat as seen in 16B, so L
It becomes below the L level and becomes F over the entire section as shown in 8B.
2, that is, a continuous trip permission signal.

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

In other words, if it is treated as a variable power supply terminal, the F2 signal will be generated in the negative half wave, making it possible to trip the breaker even if no fault current flows.

FIG. 3 shows a conventional conveyance control circuit represented by the F1 signal and F2 signal, which is installed at the power source end and uses the F2 signal continuously until the circuit is reclosed after a tripping command is issued.

Of the components shown in FIG. 3, 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.

Now, 17 is the OR gate, and 18 and 19 are the normally open contacts of the auxiliary relay.

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

Reference numeral 19 exhibits the same operating state as the contact that issues the breaker command, and is a contact of a so-called time-limited return type auxiliary relay that returns after a certain period of time after the breaker is opened.

PT represents the power supply of the transistor circuit. According to this circuit, when there is an input signal to the transmitter 13 of the information transmission device 12, the F2 signal is transmitted, and when there is no input signal to the transmitter 13, the F1 signal is transmitted to the other end (variable power supply end).

Therefore, since 19 is closed at the same time as the cutoff command is issued, a signal is continuously supplied to 13 from PT, so that a continuous F2 signal is transmitted to the other end.

As a result, the breaker tripping at the other end is caused by the output (Fl) only from the rectangular wave shaping circuit 8 at the other end.

This is further ensured by the continuous F2 signal sent by the closing operation of the contact 19, rather than relying solely on the repeated F2 signal.

In addition, when the breaker is tripped by a command from the protective relay device after contact 19 is closed, 18 is closed, and there is a continuous signal from PT to 13 until the next breaker is closed, and the other end A continuous F2 signal is transmitted.

In this way, the F2 signal is continuous until the breaker is closed again after the breaker closes command is issued.

The main role of the contact 18 is that during re-closing operation, when the breaker at the variable power supply end is closed in advance due to variations in the no-voltage time between both ends or for some other reason, even if the accident remains as a permanent accident, This is to transmit a continuous F2 signal from the power supply terminal to the variable power supply terminal and immediately cut it off again using the phase comparison relay.

If the continuous F2 signal is not sent from the power supply terminal to the variable power supply terminal in step 18, when the variable power supply terminal is turned on in advance due to a permanent fault, the variable power supply terminal will always receive a trip permission signal (F2 signal) due to the fault current. However, the circuit breaker is not yet turned on at the power supply end, and no fault current flows, so the power supply end is continuous, F
This is because the variable power supply terminal cannot open the breaker using the phase comparison relay, which delays the re-cutoff and increases the influence on the grid.

On the other hand, when the power supply terminal is turned on in advance, the current is O even if the breaker at the variable power supply terminal is not turned on, so the phase comparison relay at the variable power supply terminal transmits a continuous F2 signal, so there is no possibility of permanent failure. It is possible to re-shut off the power supply end breaker at

For this reason, it is not necessary to provide equipment for transmitting continuous F2 signals to the other end through the 18 contacts at the variable power source end, but in order to match the circuits, the circuit shown in FIG. 3 is also provided at the variable power source end.

FIG. 4 shows a continuous F2 signal detection circuit installed at the variable power source end, which detects when the breaker at the power source end is open and transmitting a continuous F2 signal.

Reference numeral 20 is a timer of a limited-time operation type, which is used to confirm that continuous F2 signals are being received.

In other words, the output of the receiver 14 of the information transmission device 12 has a level when the F2 signal is present and has no level when the F1 signal is present, but even at all times, the F1 signal and F2 signal are qualitatively repeated at a 180° cycle. The time limit T is set to 6 so that this F2 signal does not respond and outputs 20 only when receiving the continuous F2 signal.
It is normal to adjust the time to about 0 ms (time equivalent to 3 Hz in the case of a 50 Hz system).

When the timer '20 has an output, the relay amplifier 21 is driven once and the auxiliary relay 22 is activated.

That is, the operation of the auxiliary relay 22 means that the circuit breaker at the power supply end is opened.

Note that the circuits 20, 21 and 22 are provided for each phase.

FIG. 5 shows a circuit for detecting the re-closing condition, and here, as described above, if there is interconnection of two or more phases in total of two circuits, the auxiliary relay 23 is operated.

Note that a in the figure shows a circuit at the power supply end, and a shows a circuit at the variable power supply end.

5. 22-1, 22-2 and 22-3 are the contacts of the auxiliary relay 22 shown in FIG. It is a point of contact.

Also, those with a ' (dash) in 22'-1, 22'-2, and 22'-3 are the A phase of the dual-line auxiliary relay 22.

These are normally closed contacts for B and C phases.

32 is a contact that indicates the open/close state of the breaker at its own end (variable power supply end), and is 32-1.32-2.32.
-3 is not shown, but it operates at the same time as the line 1 cutoff command.
Normally closed contact of auxiliary relay that is self-held until re-closing or final cutoff, 32'-1, 32'-2゜32'-
3 similarly performs the same operation as line 2.

Items with the symbol ' (dash) that appear in the following explanation and figures are defined as those for Line 2.

Reference numeral 23 denotes an auxiliary relay for detecting reclosing conditions which is energized when detecting interconnection of two or more phases.

In other words, in the conventional reclosing condition detection circuit installed at the variable power supply terminal in Figure 5, the phase 32 of the open phase operates when the breaker at its own end is opened, and the breaker at the other end is opened. Phase 22 of the open phase operates and opens its normally closed contacts, but
If there is interconnection of two or more phases in total of two circuits, 23 is activated and the reclosing condition is satisfied.

FIG. 5a shows a conventional reclosing condition detection circuit installed at the power supply end.

6-1.6-2.6-3 are the normally open contacts of phase A, phase B, and phase C of the overcurrent relay 6 for detecting new bills on line 1, and 6'-1゜6'-2 , 6'-3 is that of Line 2.

Therefore, if the circuit breaker at either end is opened, no current will flow, and the overcurrent relay 6 will not operate, so its normally open contact will remain open.

Therefore, if there is interconnection of two or more phases in total of two circuits, the re-closing condition detection auxiliary relay 23 is activated and the re-closing condition is established.

As is clear from the explanation so far, the reclosing condition detection circuit installed at the power supply end in Figure 5a detects phase interruption by the operation of a highly sensitive overcurrent relay, so the power transmission line is connected over long distances. When the ground charging current in the protected area becomes large due to such reasons, the overcurrent relay for detecting new bills will operate due to the charging current even though the other end is cut off.
There is a habit of treating it as interconnected even though the phase is cut off.

On the other hand, if you set the overcurrent relay so that it does not operate in a charging current, it will not be able to operate even if there is actually a connection to the grid and a small current is flowing; There is a risk that the re-closing operation may be prevented inadvertently based on this judgment.

If it is assumed that there is interconnection due to charging current even though there is no interconnection, and if different systems are connected in parallel by re-closing, various power transmission equipment may be damaged, and some countermeasures will be required.

In view of the above, it is an object of the present invention to provide a new bill detection system that is necessary for correctly reinserting a circuit breaker after opening.

The present invention was made in view of these problems, and instead of conventionally transmitting a continuous trip permission signal from the variable power supply terminal when the circuit breaker operates, it now sends a continuous trip lock signal with a gradual time limit. It is something.

Therefore, in addition to eliminating the need for an overcurrent relay for detecting new banknotes, phase breakage can be reliably detected even when the charging current becomes large.

An embodiment of the present invention and its operation will be described below with reference to FIGS. 6 to 9.

FIG. 6 shows an embodiment of the conveyance control circuit according to the present invention installed at the end of the variable power source, and is an alternative to FIG. 3.

Although not shown here, 28a is a normally open contact of a timer that is energized under the reclosing circuit start condition and is excited in parallel with the no-voltage timer, and the timer is shorter than the timer that measures no-voltage time. Δt4 has been set.

29 is an inhibit gate, 30 is an ant game-1, and 31 is an or gate.

FIG. 9 shows its operating waveform, and the operation will be explained next.

Normally (before TO), both 18° and 19.28a are inactive and open, so the output of the square wave setting circuit 8 of the phase comparison relay 7 is transmitted directly to the transmitter 13 of the information transmission device 12 via 29° 31. It will be done.

Now, an accident has occurred inside the protected area, and a breaker disconnection command is issued from the phase comparison relay device at time t.

19 is closed, and this contact 19 opens at time t2 when a suitable time Δt1 has elapsed after time t1 when the breaker was opened.

During this period (to''t2), a signal is applied via the contact 19 and the OR circuit 31, resulting in a continuous F2 signal.

The contact point 18 is connected during the period when the breaker is open (11 to 1.
) is closed to provide input to the lock side terminal of the inhibit circuit 29.

During this period, the output of the inhibit circuit 29 is blocked.

By the way, the time limit of the contact 28a of the timer energized under the reclosing circuit activation condition is set to a settling time shorter than the time limit of the timer that measures the no-voltage time, and the contact 28a is activated at time t3 before the breaker is turned on. Closed for the first time.

The AND circuit 30 provides an output only during the period (ta to 1.) when both 28a and 18 are closed.

As is clear from FIG. 9, the signal sent from the variable power supply end to the power supply end is t before and after the breaker is opened.

-t2 becomes a continuous F2 signal. Then, from t2 to t3, there is a continuous F1 signal, and the t before re-closing
3 to t4 becomes a continuous F2 signal again.

Here, as described above, the continuous F2 signal has the effect of further ensuring opening of the circuit breaker at the power source end.

The subsequent continuous F2 signal is used to prevent the situation where the circuit breaker at the variable power supply terminal is turned on in advance in the event of a permanent accident, and the power supply terminal may be shut off again as described above.

In the present invention, the detection of a new banknote at the power supply terminal is performed from t2 to
By performing continuous F and double signals during t3, the conventional overcurrent relay 6 is unnecessary, thereby improving the reliability at the time of reclosing.

Figure 7 shows a cutoff command detection circuit installed at the power supply terminal, and when a continuous F1 signal is received from the variable power supply terminal, the auxiliary relay 2
7 to operate.

24 is a knot gate, 25 is a timer of limited operation type, 2
6 is a relay amplifier, and 27 is an auxiliary relay.

When the continuous F1 signal is transmitted from the other end, the information transmission device 1
Since the output level of the receiver 14 of No. 2 becomes O continuously and the output of the NOT circuit 24 becomes YES, the timer 25 is energized, and when the setting time limit of No. 25 is reached, the relay amplifier 26 is driven, and then the auxiliary relay is activated. By operating 27, the disconnection of the other end is detected.

Here, the timer 25 is the same as the timer 20 in FIG.
This is to prevent the terminal from responding to the F1 signal when the Fl and F2 signals are repeated, and to output an output only when the continuous F1 signal is transmitted from the other end.

FIG. 8 shows a reclosing condition detection circuit according to the present invention installed at the power source end, which replaces the conventional circuit shown in FIG. 5a.

Next, the operation will be explained with reference to FIG. 28b is a normally closed contact that operates in the same manner as in FIG. 6 28a, 2γ-1, 2
7-2 and 27-3 are the normally closed contacts of the A-phase, B-phase, and C-phase, respectively, of the auxiliary relay for detecting a new banknote on line 1, which operates when the continuous F1 signal is detected from the variable power supply terminal, and 27'- 1, 2
7'-2.

Similarly, 27'-3 is a normally closed contact of the A-phase, B-phase, and C-phase of the line 2 new bill detection circuit auxiliary relay.

32-1.32-2.32-3.32'-1.32'-
Reference numerals 2 and 32'-3 indicate normally closed contacts of auxiliary relays for detecting new bills for each phase on the power supply end side, which operate exactly the same as shown in FIG.

33 and 34 are the contacts of the auxiliary relay, which are not shown, but 33 is the normally closed contact of the auxiliary relay that operates at time t8, which is a gradual time period Δt2 after the re-closing execution time t4, and 34 is the auxiliary relay that operates at the re-closing final cut-off time t5. It is a normally closed contact of a relay.

35 is a normally open contact of an auxiliary relay that operates at time t7 after a gradual time limit Δt3 when the reclose circuit is activated.

Although not shown, 36 is a normally closed contact that operates at time t6 when the tracking failure occurs.

Since 23a is a normally open contact of the auxiliary relay 23, when the auxiliary relay 23 for detecting re-closing condition is activated, 33, 34, 36
The auxiliary relay 23 is self-retained through 23a.

Then, this self-holding circuit is released when a re-closing is performed and 33 is opened, or when a final cutoff is made and 34 is opened.

In this Fig. 8, normally closed contacts such as 27-1, 27-2...
The signal is received within 3 minutes, and when a new banknote is detected, the circuit is opened.

Normally closed contacts such as 32-1, 32-2, etc. open when the self-ended breaker is disconnected.

Then, at the time t7 when the time limit Δt has gradually elapsed after the re-closing circuit starts, the circuit 35 is closed and the circuit 28b is opened.
The presence or absence of two-phase interconnection is determined between t7 and t13 up to t3.

Auxiliary relay 2 for detecting reclosing conditions if there is interconnection of two or more phases
3 operates and maintains itself.

As can be seen from the above explanation, when the reclosing no-voltage time has elapsed and the reclosing is to be performed, the auxiliary relay 28b operates and opens, but if the reclosing conditions have been established by then, the auxiliary relay 23 will operate automatically. Therefore, polyphase reclosing can be reliably performed.

As described above, the present invention is configured to transmit a continuous F1 signal from the variable power supply terminal in order to detect a new bill when the circuit breaker is opened.

By the way, in Fig. 3, it was stated that if the continuous trip permission F2 signal is not transmitted before the breaker is re-closed, it will not be possible to re-shut it when the breaker is re-closed, but in this invention, as can be seen from Fig. 9, 28a with time to work
There is no need to worry about this problem since the F2 signal is operated and the continuous F2 signal is transmitted as before.

Specifically, the reclosing no-voltage time is about 0.5 seconds, while t3
Since it is sufficient to transmit the continuous F2 signal with the interval between t4 and t4 being about 0.1 seconds, 28 can be settled for about 0.1 seconds with sufficient margin.

In addition, in the case of a so-called follow-up failure in which an accident occurs during the no-voltage period after 28b is opened, 36 operates and 23
The memory of is reset once, but in order to restart the no-voltage time from the beginning, the timer 28 installed in parallel with the no-voltage timer is reenergized, so 28b is closed again and 23 is chased. The grid connection will have to be changed again after the failure occurs.

In one embodiment of the present invention shown in FIGS. 6 to 8, the presence of two-phase interconnection is detected and it is found that the condition is satisfied after restart, but the absence of two-phase interconnection is detected and the re-closing condition is not satisfied. It goes without saying that the re-closing lock may be performed by detecting this.

The gist of the present invention is to transmit continuous F and double signals to detect a circuit breaker.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the principle of the phase comparison transport protection relay system, Figure 2
The figure is an explanatory diagram of the response under various conditions of the same system, Figures 3 to 5 are conventional breaker detection circuits for reclosing conditions, and Figures 6 to 5.
FIG. 8 shows an example of a breaker detection circuit according to the present invention, and FIG. 9 is a diagram for explaining the operation of one embodiment of the present invention. 1... Bus bar, 2... Generator, 3...
... Current transformer, 4... Breaker, 5...
...Power transmission line, 6...Overcurrent relay, 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 ... Micro line, 16 ...
・Relay input current introduction circuit, 24... Knot gate, 25... Timer, 26... Relay amplifier, 27... Auxiliary relay, 28...
...Timer contact, 29...Inhibit gate, 30...And gate, 31...
・Orgate.

Claims (1)

[Claims] 1 One power station A of the power transmission line is the power source end, the other power station B
is used as the variable power supply terminal, and the trip permission signal or trip prevention signal according to the current phase of each phase of the transmission line is transmitted as an information signal between the two electrical stations, and each phase phase comparison transmission is used to control the opening and closing of each phase breaker. In the new circuit breaker detection method adopted in protective relay equipment to confirm that there is interconnection of two or more phases as a condition for reclosing after opening a circuit breaker, at least A first device installed in electrical station A that forcibly generates a continuous trip permission signal in the open state, for each circuit breaker of each phase of its own, forcibly generates a continuous trip prevention signal for a predetermined period of time during its open state. A second device installed at electric station B, installed at each end electric station, uses the open state of the circuit breaker of each phase of itself and a predetermined information signal for each phase transmitted from the other end. and a third device for detecting that there is interconnection of two or more phases.