JPS5959011A - High speed reclosing line system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for high-speed reclosing of power transmission lines in a power system.

[Technical background of the invention]

High-speed reclosing methods have been widely applied to overhead power transmission lines in power systems in combination with protective relay devices to improve transient stability of power systems and reliability of power supply. Generally, accidents involving overhead power lines are often caused by lightning strikes, and the high voltage of lightning causes the air insulation to break down, resulting in an accident. If you do, the accident will disappear,
This method has been applied with the focus on the possibility of power transmission again.

Next, a re-closing method in the event of a one-line ground fault will be described. FIGS. 1(a) to 1(c) are diagrams showing an outline of the high-speed single-phase reclosing method. In Figure 1(a), I is 2
Indicates a power transmission line composed of phases (R, S, T phases), A, B
are electric stations at both ends of the same power transmission line 1, 2 is a breaker for the transmission line at electric station A, 3 is a breaker at electric station B, and 4 is T.
Each line of the phase transmission line has a single-wire ground fault.

In this way, when the T-phase single-wire ground fault 4 occurs, the transmission line protection relay devices installed at electrical stations A and B operate,
The circuit breaker for only the T phase, which is the 9th fault phase shown in FIG. 1(b), is cut off. Then, the T phase is left in a voltage-free state for a certain period of time, waiting for recovery from the accident (that is, recovery from air insulation breakdown due to lightning strike - arc extinguishment), and then the breaker for the T phase is turned on at LL) degrees.

In this case, it is desirable that the time that the faulty phase is cut off (called the no-voltage time) be as short as possible from the standpoint of system stability and power supply, but if it is shortened, the insulation recovery of the air due to a lightning strike (arc extinction) is desirable. ) is not possible, and even if the power is turned on again, the accident will continue, and there will be no choice but to shut it off again (in this case, cut off not only the accident phase but also the gold phase).

In other words, it is desirable for this reclosing no-voltage time to be as long as possible from the perspective of recovering the air insulation at the fault point, but there are conflicting factors: from the perspective of system stability and power supply, it is better to make it as short as possible. .

However, in order to successfully reclose the circuit, it is necessary to insulate the accident point (
Arc extinction) is an absolute requirement, and it is desirable to set this no-voltage time so that the circuit breaker can be turned on very quickly after the arc at the fault point is extinguished. By doing this, there will be almost no cases where the re-closing fails, and there will be no waste of not turning on the circuit breaker even though the air insulation has been restored.

[Problems with background technology]

However, in the conventional re-closing method such as /1, this no-voltage time is uniquely determined as an empirical value, and there is no confirmation of arc extinction, etc. Therefore, re-closing is necessary. There is a serious problem if the circuit fails because the arc has not been extinguished, or conversely, if the breaker is not turned on even though the arc has been extinguished.

[Purpose of the invention]

The present invention was made in view of the above-mentioned drawbacks of the conventional system, and its purpose is to almost eliminate cases of reclosing failure, reduce fluctuations in the power system, and contribute to improving the stability of the power system. The purpose of this invention is to provide a high-speed reclosing method that allows for

[Summary of the invention]

In order to achieve the above object, the present invention detects the voltage of the new transmission line after the breaker of the fault phase is cut off in the single-phase reclosing circuit as shown in FIG. If this voltage exceeds a predetermined value, it is determined that the arc of the new transmission line has been extinguished (the air insulation has been restored), and the circuit is reclosed. It is characterized in that the voltage-free time of the circuit is not always constant, but that the circuit is reclosed on the condition that the arc is extinguished.

[Embodiments of the invention]

First, the phenomenon and principle targeted by the present invention will be explained.

Generally, as high-speed reclosing, the method of shutting off only the fault phase and reclosing, called single-phase recirculating or multi-phase reclosing, is used for ultra-high voltage systems with a system voltage of 187 kV to 5001 cV,
Furthermore, it will be applied to (7) 1000kV power transmission systems in the future. In such high-voltage power transmission lines, the capacitance between each line and between each line and ground is quite large, and the mutual inductance between each line can be ignored. Therefore, for example, if only one phase of the power transmission line is cut off, a voltage due to electrostatic induction or electromagnetic induction will be generated in the cut off power transmission line from other healthy phases or lines. Figures 2 and 3 briefly illustrate the mechanism for generating this induced voltage.

FIG. 2 shows how an electrostatic induced voltage is induced from a healthy phase power transmission line to a breaker power transmission line when one phase is cut off in a single line power transmission line. In the figure, ・5 is a healthy hR phase,
6 is the healthy S phase, and 7 is the disconnected T phase. CRR+C8s, CTT, etc. are the 1-wire ground leakage capacitance of each phase transmission line, cas, C8T r CTR is the mutual electrostatic capacitance between each phase. capacity. The voltage induced in the circuit breaker T-phase 7 Vc is as follows, where the ground voltage of each healthy phase is set to bs. Here 1. Assuming that the transmission line is completely suspended, CRR-css == CTT ”” csl C
If R8''csT==CTR='Cm, it is expressed as, and a fairly large voltage is induced in the current pair.

In addition, in this mode, the arc, etc. caused by an accident is in a state where the gobo has disappeared (a state where there is no fault on the breaker transmission line).

Next, FIG. 3 similarly shows a state in which a voltage is induced in the current pair by electromagnetic induction. In FIG. 3, 8 shows the T phase, which is a new set.

In this case, the voltage induced in the shunt is roughly expressed by the following equation.

#'r=jω paste・(iR+rs)
-(3) Here, Lm indicates mutual inductance between each phase and power transmission line. As you can see from equation (3),
The induced voltage due to electromagnetic induction varies greatly depending on the value of the current (tidal current) flowing through a healthy phase when one phase is cut off, and when the tidal current is large, a high induced voltage occurs, and when the tidal current is small, a low induced voltage occurs. become.

Note that among these induced voltages, the present invention focuses on the electrostatic induced voltage phenomenon that is not affected by tidal currents and the like, so all induced voltages described hereinafter indicate electrostatic induction.

Next, an explanation will be given of induced voltage in a state where the transmission line fault continues (the arc does not go out) even though the fault phase has been cut off due to the occurrence of a fault.

FIG. 4(a) shows how the accident continues (arc continues) even though the fault phase transmission line is cut off. In the same figure, 9 indicates a fault in the T-phase feeder line, and even though both electrical circuit breakers A and B are open, arc current continues from the healthy phase through mutual capacitance, causing the fault. It shows that it will not disappear. FIG. 4(b) shows this mode in the same way as the previous FIG. 2, and shows an accident that is still continuing in the 10th class.

Now, assuming that the fault shown in 10 is a ground fault with a resistance value close to zero, the voltage generated in this shingle assembly can be summarized using equation (2) as follows: Here, since C3-F has been short-circuited with almost zero resistance due to an accident, C8, F-equivalent to ω (infinite).

Note that this case assumes that the resistance at the fault point is almost zero, so the induced voltage is zero, but in reality there are many cases where the resistance at the fault point is not zero. However, even if this resistance is not zero, if the fault arc remains, the voltage generated in the fault phase is sufficiently lower than the voltage induced in the fault-free state according to equation (2) above. It is something.

The present invention detects the voltage induced in the fault phase after being cut off as described above, determines whether the fault is continuing based on its magnitude, and turns off the breaker when it is determined that the fault has disappeared. It is an attempt to close the circuit. To give an example of the judgment level for whether or not this accident will continue, let us say that the voltage on the T-phase transmission line side of the T-phase cut-off section is VL, and this condition is met at the format level of (η: Marnon, for example, 05). It is also possible to reclose the circuit when it is satisfied.

Next, an example of the configuration of the present invention based on the above principle is shown in FIG.
This will be explained using (b). FIG. 5(a) shows the overall configuration of the system, and in the figure, lt, s.

T indicates the power transmission line of each phase connecting electric stations A and B, and 11R
rl IB+I IT indicates the power transmission line protection relay device for each phase of electric station A. This protection device can detect transmission line faults and reclose (re-energize) the circuit breaker.
Also issues orders. 12R812s+127 is a voltage transformer for each phase (usually called a line PD, etc.) on the transmission line side of electric station A (on the transmission line side from the circuit breaker), and 13 is the judgment function Ronok of the present invention. This shows the circuit.

Note that this diagram only shows the area outside electrical station A, but
The same applies to the 4-if configuration on the B electric station side. Also,
11T for Rononok circuit 13.

Although it only describes information exchange with 12T, 11n+
Similar exchanges are required for 11s, I2R, and 12s. In other words, in the figure, if the T phase is cut off, the line voltage of the T phase is detected and introduced into this system, and it is determined whether the fault continues or not using the decision logic shown in equation (5) above. Then, the conditions for determining that the accident has disappeared are passed to the power transmission line protection relay device, which issues a re-closing command to the circuit breaker.

Next, FIG. 5(b) shows an example of the above-mentioned determination function ronok. In the figure, 14 is a power transmission line protection relay device, 15 is a 3 (1) constant function logic circuit, 16 is a voltage input from a line side PD (voltage transformer), 17 is an auxiliary transformer, and 18 is a voltage input from a relay device. The contact 19 closes upon receiving information that the power transmission line has been cut off, and 19 is a judgment unit that outputs 1" at 19A when the judgment condition is met. 20 has some confirmation time for the judgment condition. No limit sheath timer, 2
In the event that the boat is cut off due to a cut-off from the safety relay,
1” is maintained, 22 is A for the judgment condition and cutoff condition.
The ND circuit 23 is an r1 closing command to the breaker, and here it is once passed to the protective relay device, and then the command is issued from the same device to the breaker.

As described above, by configuring the system of the present invention in combination with the Jl) Leh device, an optimal system can be realized, particularly for high-speed single-phase reclosing of trunk power transmission systems with high voltage levels.

Although the figure only shows a circuit for one phase, a circuit for three phases is actually required.

Furthermore, the command to re-energize the circuit breaker may be issued directly from the main/stem without going through the IJ relay device.

Furthermore, FIG. 5 shows an example of the system configuration, and any configuration may be used as long as it is based on the determination algorithm of the present invention based on line voltage value detection.

〔Effect of the invention〕

As explained above, according to the present invention, a high-speed reclosing method that can almost eliminate cases of reclosing failure, reduce fluctuations given to the power grid, and contribute to improving the stability of the power grid can be achieved. I can do it.

[Brief explanation of the drawing]

Figures 1 (a) to (c) are diagrams for explaining the normal high-speed single-phase reclosing system, and Figure 2 shows the electrostatic induced voltage during one-phase interruption (after the breaker fault has disappeared). Figure 3 is a diagram to explain the induction of electromagnetic induced voltage. Figure 4 (a) shows when one phase is cut off, and when an accident (arc) continues in the cut-off phase. Figure 4 (b) is a diagram that explains the electrostatic induced voltage when one phase is cut off and an accident (arc) continues in the cut-off phase. (a) and (b) are configuration diagrams showing one embodiment of the present invention. 11R~IIT, 14...Protection relay device, 13゜1
5... Judgment function Ronok circuit, 19... Judgment circuit,
20...Time-limited timer, 22...AND circuit. Degan Single Agent Patent Attorney Takehiko Suzue Figure 1 (a) (b) (c) Figure 2 Figure 3 ρ Figure 4 (a) (b) Figure 5 (a)

Claims (1)

[Claims] In the high-speed reclosing method, which is implemented in combination with a protective relay device in the event of a power transmission line accident, the voltage induced in the line or circuit breaker that was disconnected due to an accident is detected, and if the voltage exceeds a predetermined value, the A high-speed re-closing method characterized in that the circuit is closed every time it is determined that the wire failure has been recovered.