JPS59175323A - Transmission line protecting relay unit - 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] [Field of Application of the Invention] The present invention relates to a transmission line protection relay type of a resistance grounding system, and is particularly applicable to line-to-line short-circuit failures caused by the three-lead jump phenomenon that occurs due to ice and snow. On the other hand, the present invention relates to a power transmission line protection relay device equipped with a three-lead jump detection circuit so as to provide an appropriate reclosing no-voltage time.

[Prior art]

In areas with heavy snowfall, resistance grounding type feed line maintenance relays are often equipped with three-lead jump countermeasures.
), high-speed single-phase reclosing, failure of two or more wires, i.e., two-wire short circuit failure (2φ-8), two-wire short circuit failure (2φ-G
), for three-wire failures (3φ-8, 3φ-G), a low-speed three-phase recirculation method of several minutes or a medium-speed three-phase recirculation method of several seconds is adopted.

By the way, with such a one-line protection relay, it is desirable to perform high-speed three-phase reclosing for about 20 cycles in combination with a high-speed protection relay in case of a failure of two or more wires. In transmission lines where three-lead jumps lead to line-to-line short circuits, it usually occurs repeatedly at intervals of several seconds, so if high-speed rerouting is performed, it is likely to fail. Medium or low speed three-phase reclosing shall be performed in such cases. However, in the past, it was difficult to distinguish between short-circuit faults caused by three-lead jumps and normal short-circuit faults, so only medium-speed or low-speed three-phase reclosing was performed for short-circuit faults without distinguishing between the two. .

[Purpose of the invention]

The purpose of the present invention is to completely distinguish between short-circuit faults caused by three-lead jumps and normal short-circuit faults, to perform medium-speed or low-speed three-phase reclosing only in the case of short-circuit faults caused by three-lead jumps, and to perform medium-speed or low-speed three-phase reclosing only in the case of short-circuit faults caused by three-lead jumps. Accordingly, it is an object of the present invention to provide a power transmission line image retention relay device that employs high-speed three-phase reclosing.

[Summary of the invention]

The key point of the present invention is that when the feed tS is short-circuited due to a three-lead jump, the pure 2φ
-8, only pure 2φ-8 is detected, and when this is detected, the no-voltage time setting timer of the three-phase reclosing circuit is switched from high speed to medium speed or low speed. This is what I did.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a single-line power transmission line connecting electric station A and electric station B in a resistive grounding system. In the figure, 1 indicates a power supply and 2 indicates a neutral point grounding resistor. Now, if a two-phase short circuit occurs between the C phase and the b phase due to a three-lead jump at point F in the figure, a fault current lAlIb flows in the electrical station A. In addition, as shown at each end of the bus voltage at electric station A and electric station B, the line voltage V1b between the C phase and b phase decreases as shown in the vector diagram, but the line voltage V1b between the C phase and C phase decreases as shown in the vector diagram. Line-to-line 'm pressure V between phase and C phase
b e Hv6. voltage drop is small. As described above, in the case of pure 2φ-8 due to three-lead jump, only the line-to-line voltage between the two short-circuited lines decreases significantly, so it is understood that it is sufficient to detect this. FIG. 2 shows a schematic diagram of a circuit for detecting a pure two-phase short circuit and a timer starting circuit for setting the no-voltage time of a three-phase reclosing circuit. 3al in the figure,
3a2.3b are undervoltage relays (not shown) configured to operate on line voltage installed at electrical station A and B.
Normally closed contact (3al l) of C phase (operated by V-b)
382 ) and a normally open contact (3b), 4as +
4az + 4b and 5 al + 5 a2+ 5
b indicates similar contacts in the B phase (operates with VB) and C phase (operates with V), respectively (note that the normally closed contacts are closed when the voltage is correct; (■ indicates a contact that closes when positive pressure decreases.) o 6ai * 6 a
2T 6 b is the C-phase normally open contact (6 at
, 6az) and the normally closed contact (6b) p, , 7
a1.7az, 7b and 8al, 8a2+ 8b indicate similar contacts of the b phase and C phase, respectively, and the circuits marked with * in the figure are the corresponding parts. 9 is a contact that opens when the earth fault overvoltage relay (not shown) is operated, and 10 is an undervoltage relay and an overcurrent relay. Auxiliary relay 7 for detection, 10 as +10a2
and 10b are its operationally closed and operationally open contacts, respectively. Reference numeral 11 indicates a contact point for a restart signal, which closes when the circuit is cut off at high speed by, for example, a carrier relay device. Reference numerals 12 and 13 indicate timers for setting the re-closing no-voltage time, and 12 is for high-speed re-closing, which is normally activated in series by the re-closing starting signal 11. 13 is for medium speed or low speed reclosing.

Reference numeral 14 indicates a contact that opens when the recirculation is performed or when the reclosing conditions are not satisfied, and is necessary for releasing the self-holding state of the auxiliary relay 10.

Now, at point F in Figure 1, phase a to b due to three-lead jump.
The effect of the present invention when a two-phase short circuit occurs between phases will be explained in detail. As shown in the vector diagram, the eg, EEV, and b of phases a and b decrease, so the undervoltage relay of phase C is activated. In Figure 2, 3b is closed and 4a
If 1.5ax remains closed, the auxiliary relay 10 operates and maintains itself via 14. In this case, since it is a pure two-phase short circuit, the ground fault overvoltage relay is inoperative and the circuit 9 remains closed. 10 operates and uses a pure two-phase short circuit, contacts 10a1 of the same relay close, 10
b is opened, the reclosing no-voltage time is switched from timer 12 to timer 13, and medium-speed or low-speed reclosing is performed. In addition, when the fault currents I- and Ib are large and the bus voltage drop is small at the power station A, the C-phase and B-phase overcurrent relays 6a1 and 7a2 are activated by the circuits marked with * in Fig. 2.
is in operation, and 8b is inoperable, so there is no problem since a two-phase short circuit is detected. For faults accompanied by ground faults other than three-lead jumps, the ground fault overvoltage relay operates and 9 opens, and in the case of three-wire faults, the line voltage drops in all three phases (not shown) or , since the fault current flows into all three phases, the auxiliary relay 10 is
does not operate, and when the cylinder speed is cut off due to such a failure, the shutoff timer 12 is activated by the contact 11, and high-speed re-closing is performed, thereby achieving the object of the present invention.

〔Effect of the invention〕

According to the present invention, high-speed reclosing is performed in response to normal failures, and a great effect can be expected in maintaining the stability of the power system. Additionally, in general, carrier relay devices, etc.
As failure detection relays, an underpressure relay and an overflow relay are provided (A), so they can be used in common.

[Brief explanation of the drawing]

Figures 1 (a), (b), and (c) are explanatory diagrams of the failure mode at the time of a two-phase short circuit failure in a power transmission line, and Figure 2 is a reclosing kq! of the present invention that detects a pure two-phase short circuit. FIG. 3 is a sequence diagram of a non-starting pressure time setting timer circuit. 3a+, 3az, 3b... A and b contacts of undervoltage relay C phase, 4as, 4a2, 4b... Undervoltage relay B phase, 5al, 5a2.5b... Undervoltage relay C phase, 6as + 6a2+ 6b”・Overcurrent relay C phase a and b-i points, 7 at * 7 R217b
...Overcurrent relay b phase, 8al, 8a2, 8b・
"Overcurrent relay C phase, 10... Auxiliary relay. Agent: Patent attorney Akio Takahashi

Claims (1)

[Claims] 1. Undervoltage relays and overcurrent relays are used to distinguish line-to-line short-circuit failures caused by the so-called three-lead jump phenomenon that occur due to ice and snow in resistance-grounded power transmission lines from normal failures and to detect only three-lead jumps. Equipped with a three-lead jump detection circuit based on a combination of operating conditions,
A power transmission line protection relay device characterized in that the reclosing no-voltage time is set separately for a normal failure and a three-lead jump.