JP3372055B2 - High-speed reclosable grounding device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage power transmission line, in which a single line is formed by a reverse flashover generated between arc horns on a power transmission line. The present invention relates to a high-speed reclosable grounding device used to reclose a transmission line at a high speed when a ground fault occurs, particularly, in the other phase of the same line as the phase in which the ground fault occurred. Even if a trailing ground fault occurs with a time difference from the ground fault,
The present invention relates to a high-speed reclosable grounding device capable of retransmitting power by reclosing a circuit breaker. 2. Description of the Related Art When lightning strikes a transmission line, a reverse flashover occurs in an arc horn of a series of insulators suspended on the transmission line. Most of the accidents that occur in transmission lines are single-line ground faults caused by this reverse flashover. In order to eliminate the fault due to the ground fault, it is only necessary to set the fault section to no voltage and extinguish the reverse flashover which is the cause of the fault. Specifically, it is effective to cause the circuit breakers for the transmission line at both ends of the failed transmission line to perform the reclosing operation. The reclosing operation is to open the pole once, set the fault section to no voltage, extinguish the reverse flashover, and then turn it on again. By performing such a reclosing operation,
Retransmission can be performed without a power failure. As a typical method of reclosing, there is a single-phase reclosing method. This single-phase reclosing method is widely used because of its small power fluctuation and excellent transient stability. However, in recent years, with the increase in power demand, UHV transmission lines such as 1100 kV have been used as high-voltage transmission lines. When a single-phase reclosing is performed on this UHV transmission line, electrostatic electromagnetic induction received from another phase of the same line or another line that is paralleled is larger than in the case of the conventional 500 kV system. If such electromagnetic induction from other phases is large, the reverse flashover is extinguished when a reverse flashover of the arc horn occurs, even if the circuit breakers at both ends of the fault section are opened. It becomes difficult to do. Therefore, in a high-voltage transmission line such as a UHV system, a grounding switch is installed in each phase of the high-voltage transmission line in order to extinguish reverse flashover. In other words, after the location where the accident occurred is cut off from the transmission line by circuit breakers at both ends, this grounding switch is turned on at high speed in coordination with the switching operation of the circuit breaker, so that the electromagnetic induction current arc sustained by the insulator connected arc horn Is extinguished and the opening operation is immediately performed to cut off the induced current, thereby enabling the power transmission by the reclose circuit of the circuit breaker. [0004] A protection system employing this grounding switch will be specifically described below with reference to the drawings. FIG. 4 is an explanatory diagram showing the configuration of this system. In the figure, 1 is a bushing and 3 is a UHV-type steel tower. Reference numeral 2 denotes a high-voltage transmission line, which has three lines of an upper phase, a middle phase, and a lower phase, and is stretched between the bushing 1 and the tower 3 or between the towers 3. Each tower 3 has an insulator 3b with an arc horn 3a.
And the transmission line 2 is connected to the tower 3 by the insulator string 3b.
Suspended. At both ends of the fixed section of the transmission line 2, a circuit breaker GCB and a ground switch HSES are provided. In addition, 4 is a thundercloud and 5 is lightning. In this system, when a lightning strike 5 falls from a thundercloud 4 on a certain line of a three-line power transmission line 2, a reverse flashover 3c is generated in an arc horn 3a of an insulator string 3b suspending the transmission line 2, and a transmission is performed. The tower 3 from the electric wire 2 through the reverse flashover 3c
An earth fault fault current flows, and a ground fault occurs. [0005] The circuit breaker GCB and the earthing switch HS in the event of a single-line ground fault due to the reverse flashover 3c
The operation sequence of the ES will be described with reference to the operation sequence diagram of FIG. That is, before the occurrence of the ground fault, the circuit breaker GCB is in a closed state, and the ground switch HSES is in an open state. When a ground fault occurs in the power transmission line 2, the circuit breaker GCB first performs an opening operation after a lapse of a time T1 which is a transmission line fault detection and protection relay time. However, an induced current flows through the accident transmission line 2 due to electrostatic electromagnetic induction from another phase, whereby the reverse flashover 3c is still maintained between the arc horns 3a. Therefore, in a state where the circuit breaker GCB is opened, the grounding switch HSES is forcibly turned on at a high speed, and the induced current grounded in the arc horn 3a is guided to the grounding switch HSES side, thereby forming an arc. The reverse flashover of the horn 3a is extinguished. Ground switch
After the reverse flashover is extinguished by continuing the closed state for θ hours, the switch returns to the open state to cut off the induced current, and finally the circuit breaker performs the closing operation to restart the power transmission. Next, a ground fault current and a current flowing through the grounding switch HSES will be described with reference to FIG.
As described above, the transmission line 2 has an upper phase, a middle phase, and a lower phase, and a predetermined load current flows in each phase. Assume that it has occurred. In the middle phase of the transmission line 2, T01 in the figure is
02 is the start of the opening operation of the circuit breaker GCB, and the fault current flows only in the middle phase of the transmission line 2 between T01 and T02. However, since the middle phase of the transmission line 2 receives electrostatic and electromagnetic induction from the upper and lower phases, which are other sound phases, and other parallel lines, the arc horn is opened when the circuit breaker is opened. Since the reverse flashover caused by the induced current still occurs in the power supply, the ground switch is turned on to extinguish the reverse flashover. Then, as shown in FIG. 6, after the closing point T03, a ground fault current including a DC component and an electromagnetic induction current are superimposed on the grounding switch, and a current shifted from a current zero point flows into the grounding switch. Then, as the ground fault current is grounded, the electromagnetic induction current component increases and an alternating current passing through the current zero point flows. Therefore, when the induced current is interrupted by the grounding switch, the opening operation is performed by capturing the timing at which the current becomes zero. However, such an electromagnetically induced current is
As shown in FIG. 8, when the current is interrupted, as shown in FIG. 8, the transient recovery voltage in which the transient phenomenon of the electric circuit and the electrostatic induction voltage received from the other line by the faulty transmission line are superimposed as shown in FIG. Is applied. Such a relatively large current and the interruption of the transient recovery voltage condition of a relatively large rising rate and a high peak value are interrupted by a parallel-type grounding switch which merely opens and closes a rod-shaped contact in SF6 gas. And a grounding switch having a puffer type arc-extinguishing chamber like a circuit breaker is required. FIG. 9 shows a specific configuration of a device conventionally known as the above-mentioned grounding switch. This grounding switch is housed in a grounding tank 19 filled with an insulating gas, and a conductor 11 connected to the transmission line side is provided at the center of the tank 19, and a fixed electrode 12 is provided at a part thereof. ing. A movable electrode 13 is provided on a portion of the tank 19 facing the fixed electrode 12.
Are supported so as to be able to approach / separate toward. This fixed electrode 1
2 is connected at its base to an operating device (not shown). A nozzle 14 for guiding an arc-extinguishing gas is provided concentrically with the movable electrode 13 on the tip side of the movable electrode 13. The nozzle 14 is fixed to a tip of a puffer cylinder 18 which is arranged concentrically on the outer periphery of the movable electrode 13. The base of the puffer cylinder 18 is
, And reciprocates with the movable electrode 13 toward the fixed electrode. A space between the movable electrode 13 and the puffer cylinder 18 is a puffer chamber 16, and the tip side thereof communicates with the nozzle 14. A fixed puffer piston 17 is provided on the base end side of the puffer chamber 16 (the side opposite to the nozzle 14). The puffer piston 17 includes the movable electrode 13 and the puffer cylinder 1.
8 is freely slidably mounted. When the conventional grounding switch having such a configuration is brought into the open state as shown in FIG. 9, an operating device (not shown) is driven to move the movable electrode 13 and the puffer cylinder 18 to the tank 19 side. (Down in the figure) to separate the fixed electrode 12 and the movable electrode 13 from each other. Then, the volume of the puffer chamber 16 between the moving puffer cylinder 18 and the fixed puffer piston 17 is reduced, and the insulating gas inside the puffer chamber 16 becomes the arc-extinguishing gas 21 and is blown out from the nozzle 14 to be fixed. The arc between the electrode 12 and the movable electrode 13 is extinguished. FIG. 10 shows the relationship between the stroke 20 of the movable electrode 13 and the puffer pressure ΔP in the puffer chamber 16 in this case. That is, the puffer pressure reaches the maximum value in a stroke approximately half of the opening stroke of the movable electrode 13, and the pressure decreases with the completion of the opening. [0010] By the way, when the current is interrupted by the earthing switch as described above, another phase adjacent to the transmission line, for example, at time T04 in the upper phase of FIG.
When a follow-up failure with a large DC current component occurs, an induced current with a large DC current component caused by electromagnetic induction due to the fault current in the upper phase flows through the medium-phase transmission line, and as shown in part A of FIG. A zero-miss current that does not form a current zero point flows through the middle-phase ground switch. It is much more difficult to cut off this zero-miss current than to cut off the zero point of ordinary alternating current, and it exceeds the capability of a conventional earthing switch. As a result, when the follow-up failure occurs exactly at the same timing as the opening timing of the middle-phase earthing switch, if the follow-up failure current includes a large amount of DC current, reclosing is not realized, A severe problem will arise for high voltage power transmission. This point will be described in detail according to the operation of the earthing switch shown in FIG. First, in the apparatus shown in FIG. 9, the insulating arc-extinguishing gas in the puffer cylinder 18 is generated between the fixed-side and movable-side contacts 12 and 13 until the movable-side contact 13 stops the opening operation. The arc is extinguished, the arc is extinguished, the current is interrupted, and the voltage tolerance between poles after the current is processed. However, considering the transient recovery voltage performance at the time of opening required for the earthing switch, the transient recovery voltage peak is obtained in a half cycle of the commercial frequency as shown in the waveform of FIG. A speed equivalent to that of a circuit breaker is required, and the time t from the start of opening in FIG. 10 to the end of stroke is short,
The actual gas flow blowing time when ΔP is equal to or more than a certain value is limited to about two cycles. On the other hand, if the follow-up failure occurs in the adjacent phase as described above immediately after the earthing switch opening operation and before the earthing switch completes the current interruption, the current zero point as shown in part A of FIG. A condition arises in which an induced current (about several thousands A) that does not form a current flows for about four cycles. In this case, the arc extinguishing mechanism of the alternating current makes it difficult to extinguish an arc that does not form a current zero point. An arc will continue to form between the poles. Then, even after the current zero returns to the restored arc current, the arc extinguishing state remains in the arc extinguishing state because the gas flow blowing time from the puffer chamber, which is about two cycles, has already elapsed. The present invention has been proposed in order to solve the above-mentioned problems of the prior art. The purpose of the present invention is to generate a back-to-back ground fault in another phase after a single-line ground fault occurs. However, even during the opening of the grounding device in the accident occurrence phase, the induction current in the accident occurrence phase can be reliably shut off, and the high-speed re-closing of the circuit breaker can be performed thereafter. An object of the present invention is to provide a closed-circuit grounding device. [0014] In order to achieve the above object, the present invention is provided in each phase of a high voltage transmission line connecting a circuit breaker, and an insulator link provided on the transmission line is provided. In response to a single-line ground fault caused by reverse flashover in the arc horn, the closing operation at the both ends of the transmission line is opened at a high speed, and the opening operation is performed after the reverse flashover is extinguished. In a high-speed reclosable grounding device provided with a grounding switch, the grounding switch is connected to a first grounding switch.
And, the other of the first second grounding switch connected in parallel to the grounding switch provided in each phase, the phase of the transmission line, the phase of the same line in which the ground fault occurs In the phase, a transmission line accident detection protection relay for detecting that a back-to-back ground fault has occurred with a time difference from the ground fault has been connected, and the contact has been opened since an opening command was output to the first switch. During the operation, when the power transmission line fault detection and protection relay detects the trailing ground fault accident, it immediately issues a closing command to perform a closing operation to the second switch, and continues. And a control unit that issues an opening command to perform an opening operation after the ground fault in the other phase is eliminated by opening the circuit breaker of the other phase . In the present invention having the above configuration,
When a back-to-back ground fault occurs in another phase of the same line where the influence of electrostatic electromagnetic induction is large within a certain time difference from the time when the opening command is issued to the first grounding switch of the ground fault occurrence phase Then, the ground fault detection protection relay of the phase in which the follow-up fault occurs generates a ground fault detection signal. Based on this detection signal, the first opening / closing
The opening operation has been performed since the opening command was output to the
During the transmission line fault detection and protection relay,
When an accident is detected, the closing operation is performed on the second switch.
An instantaneous turn-on command is issued to turn on the second grounding switch. Later, the follow-up failure of the other phase was resolved,
An opening command is issued to the second grounding switch in view of the timing when the zero-point miss current disappears, and the induced current in the ground fault occurrence phase is cut off at the current zero point by the second grounding switch. I do. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the high-speed reclosing and grounding apparatus according to the present invention will be specifically described below with reference to FIGS. The same parts as those in the conventional technique shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. (1) Configuration of the Embodiment FIG. 1 is a configuration diagram of a system including this embodiment. As shown in FIG. 1, circuit breakers GCB are provided at both ends of the transmission line 2 of each phase constituting the same circuit as in the prior art.
Near the circuit breaker GCB, there are provided first and second ground switches HSES-A, B connected in parallel with each other. The earthing switches HSES-A and B of each phase are connected to the operation control unit 10, respectively.
It opens and closes based on a closing command and an opening command from 0 to extinguish the reverse flashover 3c generated in the arc horn 3a and cut off the induced current. The operation control unit 10 of the earthing switch is connected to a transmission line fault detection protection relay Ry for detecting a ground fault of each phase. This protection relay Ry
Is to detect a ground fault in the phase in which it is provided, and send a detection signal to the operation control unit 10. Conventionally known detecting means can be appropriately used as the ground fault detecting means. In the present embodiment, a current transformer CT is provided in the vicinity of the circuit breaker GCB of each phase, and the current is transmitted by the current transformer CT. The ground fault is detected by monitoring the current of the electric wire 2. The configuration of the operation control unit 10 is as shown in FIG. This operation control unit 10
An input unit 10a of an opening command of the grounding switch HSES of the ground fault occurrence phase and a detection unit 10b of a trailing ground fault detection signal input from the protection relay Ry of another phase of the same line are provided. After this, the detection unit 10b of the trailing ground fault detection signal
Means that the operation holding time is between 1 and 5 cycles as an example.
Is connected to a time holding timer 6 whose setting can be changed, and the time holding timer 6 and the input section 10 a of the opening command are connected to an AND circuit 7. The AND circuit 7 has a closing command output unit 8 for the second ground switch and opening command outputs 9A and 9B for the first and second ground switches. Opening command output section 9B
Is, for example, to set the post-timed operation time from 1 cycle to 1
Set the post-timer operation timer 10c that can be changed in seconds.
The operation control unit 10 is connected to a second ground switch HSES-B outside the operation control unit 10. The opening command input unit 10a is directly connected to the opening command output unit 9A of the first grounding switch, without going through the AND circuit 7 or the timed operation timer 10c. (2) Operation of the embodiment In this embodiment having the above-mentioned configuration, as shown in FIG. 3, when a single-line ground fault occurs in a certain phase, the power transmission line 2 in that phase causes an accident. At time T1 after the occurrence, the circuit breaker GCB opens and cuts off the current. Then, at a certain timing, the first
GSES-A ground switch is turned on and the arc horn 3
The reverse flashover 3c of a is extinguished. An opening command is issued to the input ground switch HSES-A after a lapse of a predetermined time T2. This opening command is input to the operation control unit 10 from the input unit 10a, and is sent from the opening command output unit 9A of the first ground switch to the first ground switch HSES.
-A is output to start the opening operation,
An instruction to start counting the operation holding time is given to the time holding timer 6. In this state, if the trailing ground fault does not particularly occur in another phase, the opening of the first grounding switch HSES-A is successful, the induction current is cut off, and the circuit breaker GCB is subsequently turned on. The transmission line is reclosed. However, if a back-to-ground fault occurs in a phase other than the operating phase of the first earthing switch HSES-A during opening, a zero-point miss current is generated due to the influence, and the opening operation as described above is performed. In such a case, the interruption of the induced current may not be possible. Therefore, in this embodiment, when a trailing ground fault accident of another phase is detected by the transmission line fault detection protection relay Ry , a ground fault fault detection command of the other phase is transmitted to the operation control unit 10 of the already operating phase. I will When the other-phase ground fault detection command is received immediately after the opening of the first grounding switch HSES-A, that is, within the operation holding time of the time holding timer 6 (generally about 5 cycles), the time holding timer 6
The other-phase ground fault detection command is input to the AND circuit 7 via the. Only when the AND condition between the other-phase ground fault detection command and the opening command for the first grounding switch HSES-A already input to the operation control unit 10 is satisfied, the second condition is satisfied. Is output from the output unit 8, and the second earthing switch HSES-A re-inputs the transmission line 2 in the accident phase. The return of the closing command to the second grounding switch becomes a count start command to the post-timed operation timer 10c.
From B, an opening command is issued to the second ground switch HSES-B. At this point, the back-to-ground fault accident of the other phase has already been eliminated by the action of the circuit breaker and the earthing switch of the other phase, and for example, the zero point miss current that continues for about four cycles has been eliminated, so that the opening operation is performed again. In the second earthing switch, the induced current in the accident phase can be interrupted by utilizing the current zero point by the arc-extinguishing gas flow from the puffer chamber. Generally, the second grounding switch HSE
Protection relay Ry of the follow-up accident phase which becomes the SB opening command
Is output based on the opening operation of the circuit breaker in the phase of the follow-up accident. Therefore, even if the second earthing switch is opened immediately after being turned on, the Is eliminated. Therefore, the second grounding switch may be configured to perform the opening operation immediately after the second grounding switch is turned on, without using the post-timed operation timer 10c in the control unit 10. As described above, according to the present invention, when a back-to-back ground fault occurs in another phase and the current cannot be cut off by the first grounding switch, the second By turning on the earthing switch, and opening after a certain period of time, the induced current that does not form a zero point in the operating phase due to electrostatic or electromagnetic induction due to a trailing ground fault in another phase is reliably cut off It is possible to provide a high-speed reclosable grounding device capable of high-speed reclosing even in the event of a trailing ground fault.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system configuration diagram showing one embodiment of a high-speed reclosable grounding device according to the present invention. FIG. 2 is a circuit diagram showing an operation control unit section in the embodiment in FIG. FIG. 3 is an operation sequence diagram in the embodiment of FIG. 1; FIG. 4 is a system configuration diagram showing an example of a conventional ground switch. FIG. 5 is an operation sequence diagram of a conventional ground switch. FIG. 6 is a characteristic diagram showing a change in a current flowing through a grounding switch and each phase. FIG. 7 is a waveform diagram showing characteristics of an electrostatic induction current and an electromagnetic induction current from another phase to an operation phase of the grounding switch. FIG. 8 is a transient recovery voltage waveform diagram when the grounding switch is opened. FIG. 9 is a sectional view showing an open state of an electrode portion in a conventional puffer-type grounding switch. FIG. 10 is a graph showing a relationship between a puffer chamber pressure and an operation stroke in the grounding switch shown in FIG. 9; [Description of Signs] GCB: Circuit breaker HSES-A: First ground switch HSES-B: Second ground switch CT: Current transformer Ry: Transmission line accident detection protection relay 1: Bushing 2: Transmission line 3 ... Tower 6 ... Time keeping timer 7 ... And circuit 8 ... Opening command output unit 9A ... Opening command output unit 9B of the first grounding switch 9B ... Opening command output unit 10 of the second grounding switch 10 ... Grounding switch Operation control unit 10a: Opening command input unit 10b: Other phase trailing ground fault detection command input unit 10c: Timed operation timer

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroaki Toda 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Hamakawasaki Plant of Toshiba Corporation (56) References JP-A-5-199653 (JP, A) JP-A-55-92530 (JP, A) JP-A-61-139206 (JP, A) JP-A-61-51632 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02B 13 / 02,13 / 075 H01H 33/70-33/99 H02H 1/00-3/07 H02H 7/22-7/30

Claims (1)

(57) [Claims 1] One line is installed in each phase of a high-voltage transmission line connecting a circuit breaker, and one line is formed by reverse flashover in an arc horn of a series of insulators provided on the transmission line. In the event of a ground fault, a high-speed switching device provided with a grounding switch that performs a closing operation at a high speed with the circuit breakers at both ends of the transmission line being opened, and performs an opening operation after the reverse flashover is extinguished. In the closed-circuit grounding device, the grounding switch is a first grounding switch, and a second grounding switch connected in parallel to the first grounding switch is
Provided to each phase, the phase of the transmission line, transmission detects that the rear chase ground fault with the ground fault and the time difference in the other phases of the phase and the same line of the ground fault has occurred has occurred A wire fault detection protection relay is connected, and during the opening operation after the opening command is output to the first switch, the power line fault detection protection relay detects the trailing ground fault. In such a case, a closing command is immediately issued to perform the closing operation to the second switch, and a ground fault in the other phase is caused by the opening of the circuit breaker in the other phase.
Fast reclosing ground apparatus characterized in that a control unit that emits opening command to perform the opening operation after being removed Ri.