JPH0520976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a backup system for centralized loop protection relays.

Conventional technology Loop power transmission and distribution, as shown in the single-loop method shown in Figure 2, uses the same substation as a power source to supply power to loads via loop-shaped transmission and distribution lines, and displays line connections at selected and disconnected fault sections. A relay system is adopted, and there is a centralized processing system shown in FIG. 2 that corresponds to this relay system. In a loop power transmission/distribution line that connects a power supply substation bus 1 to load buses 2 to 5 in a loop and has sheath disconnectors 6 to 15 at each load end and substation, the central processing unit 16 calculates the substation voltage and The current detection signals of both transmission and distribution lines are transferred to transformer 17 and current transformers 18 and 19.
The A/D converter 20 captures the current detection signal at each load end and sends the current detection signal to the current transformers 21 to 28 and slave stations 29 to 28.
32 and the loop-shaped signal line 33.
By the calculation method shown in the figure or Fig. 4, the
I choose ~15 and decline. The slave stations 29 to 32 are
The detected currents of the current transformers 21 to 28 are A/D converted and sent from the transmitter (T) to the signal line 33 to the central processing unit 16, and the shear break command from the device 16 is sent to the signal line. 33 is received by the receiving section (R), and the trip circuit causes the shear disconnectors 8 to 15 to be disconnected.

In FIG. 3, the relay elements R in the central arithmetic processing unit 16 are combined so as to intersect with each other, and when a failure occurs in each section, a loop breaker shown by a broken line is disconnected from each relay element R. In FIG. 4, the relay element R causes the shears on both sides of the section to be doubly disconnected.

Problems to be Solved by the Invention When the conventional loop protection relay cannot eliminate an accident due to an abnormality in the central processing unit or slave station, a backup relay 3 is installed at the power substation.
4 and 35 (Fig. 2) caused the disconnectors 6 and 7 to fail, resulting in a problem in which the power outage range was wide.

For example, in the case of power loss failure of slave station 2, current transformer 2
1 and 22 cannot be transmitted to the device 16, and a trip command from the device 16 to the slave station 2 cannot be received. At this time, if the device 16 regards the information of the current transformers 21 and 22 as zero and continues the protection calculation, the processing method shown in FIG.
1 and 22 (R _A , R _B , R _C ,
_Normal operation cannot be obtained for relay elements R (R _A , R _B , R _C ) in the method shown in Fig. 4.
Normal operation cannot be obtained.

Also, depending on the setting of the relay sensitivity, it may malfunction due to constant current, or the breaker 10, the breaker 15,
Malfunctions may occur due to accidents outside the protection range up to 7. In order to avoid this, if a method is used to lock the relay elements that use the data of the faulty slave station, conversely the fault within the section of the slave station 29 cannot be removed, and the operation of the backup relay 34 in the power supply substation is reduced. The range of power outages will be expanded.

Means and Effects for Solving Problems The present invention provides an overcurrent relay for short circuit protection and a ground fault direction relay for ground fault protection at the end of a power supply substation, and includes an abnormal slave station detection means and a detection means for detecting an abnormal slave station. A lock means is provided for locking all relay elements using the detection information of the abnormal slave station, and furthermore, the detection signal of the overcurrent relay, the detection signal of the backup relay element such as the ground fault direction relay, and the detection signal of the abnormal slave station detection means are provided. A trip circuit is provided that trips the disconnector at both ends of the abnormal slave station when each condition of the signal is satisfied, and in order to satisfy the conditions, the detection signal of both relays is set to be shorter than the operating time of the backup relay at the end of the power supply substation. It is also characterized in that the determination is made with a delay using a timer that has a longer time limit than the operating time of other relay elements.

Embodiment FIG. 1 is a main circuit diagram showing an embodiment of the present invention. A ground fault direction relay 41 and an AC overcurrent relay 42 are respectively provided at the power substation ends (A and B in Fig. 2), and their protection outputs are logically ANDed after time limits Tθ ₁ and Tθ ₂ by timers 43 and 44, respectively. It is used as a condition input to the circuit 45. The detection data of the abnormal slave station detection means 46 is given as another condition input to the determination circuit 45.

When the condition of the determination circuit 45 is met, the trip circuit 46 obtains a trip output that disconnects the loop circuit breaker at both ends of the abnormal slave station. Here, both ends of the abnormal slave station mean the entire protection range of the relay element whose calculation data is the alternator detection signal obtained from the abnormal slave station.

In addition to such backup, the central processing unit 16 or external device is provided with a locking means 48 for locking all relay elements using detection information of an abnormal slave station.

In such a backup configuration, if, for example, the slave station 29 becomes abnormal, the locking means 48 locks the relay elements R _A , R _B ,
R _C and R _D are locked. In this operating state, in the event of an accident in each section from point _S1 to _S5 , the sheath disconnectors 6 and 10 are tripped by the trip circuit 47 shown in FIG. 1, thereby eliminating the accident. Here, even if the accident is outside the section, if the accident is inside the loop, the ground fault direction relay 4
1 and overcurrent relay 42 are operated, timers 43 and 44 are provided, and in the event of a section fault, the fault is eliminated by the operation of other normal relays. Therefore, the time limits Tθ ₁ and Tθ ₂ of the timers 43 and 44 are set as follows, respectively.

T _B > Tθ ₂ > T (short circuit) T _B ′> Tθ ₁ > T′ (ground fault) However, T _B is the operating time of the overcurrent relay of the backup relays 34 and 35 in the power substation,
T _B ' is the operating time of the ground fault direction relay of the relay 34, and T and T' are the operating times of the relay element R that operates based on the detection data from the normal slave station.

Due to these conditional operations, for example, an accident at point S ₆ (Fig. 3) in a faulty state of the slave station 29 will cause a trip in the shield disconnectors 6 and 10 and a trip in the shield disconnectors 11 and 12, which can also cause a blind spot accident. I can handle it.

Similarly, in the processing system shown in FIG. 4, relay elements R _A , R _B , and R _C are locked in a failure state of slave station 29, and the trip operation in the event of an accident is performed in the same manner as described above.

Effects of the Invention According to the present invention, when an abnormal slave station occurs, all relay elements that use the detection data of the slave station are locked,
Ground fault faults detected by ground fault backup relays such as ground fault direction relays at the end of power supply substations and short circuit faults detected by short circuit back-up relays such as overcurrent relays occur due to abnormalities at both ends of the slave station. Since it is possible to respond to accidents by quickly disconnecting the disconnector, it has the effect of minimizing the range of power outages caused by accidents while simplifying backup means. Furthermore, by appropriately setting the time limits of the timers 43 and 44, it is possible to reliably eliminate an external accident caused by an abnormal slave station.

[Brief explanation of the drawing]

FIG. 1 is a main circuit diagram showing an embodiment of the present invention;
Figure 2 is a configuration diagram of a centralized processing type loop protection relay.
3 and 4 are equivalent circuit diagrams showing the processing method of the relay element of the central processing unit in FIG. 2. FIG. 1... Power substation busbar, 2, 3, 4, 5... Load busbar, 6, 7, 8, 15... Shiya disconnector, 16...
...Intensive processing unit, 20...A/D converter, 2
9, 30, 31, 32...Slave station, 33...Signal line, 34, 35...Backup relay, 41...
...Ground fault direction relay, 42...Overcurrent relay, 4
3, 44...Timer, 45...Judgment circuit, 46...
... Abnormal slave station detection means, 47 ... Trip circuit, 4
8... Locking means.

Claims (1)

[Claims] 1 A central processing unit that sends current detection signals at the power substation end and load end of the loop power transmission and distribution line from a slave station to a centralized processing unit, and gives a command to the slave station to remove the fault section using a relay element in the unit. A processing type loop protection relay includes backup relay elements such as a ground fault direction relay and an overcurrent relay provided at the end of a power substation, a detection means for detecting an abnormality in the slave station, and a detection means for detecting an abnormal slave station by the detection means. lock means for locking the relay element using information; and a detection signal of the backup relay element having a time limit shorter than the operation time of the backup relay at the end of the power substation and longer than the operation time of the relay element. A centralized processing type loop protection relay comprising: a timer that delays the output of the abnormal slave station; and a trip circuit that trips the circuit breakers at both ends of the abnormal slave station when the output of the timer and the conditions for the occurrence of the abnormal slave station are satisfied. Backup method.