JPH03214076A - Fault section detector for substation - Google Patents

Abstract

PURPOSE:To enable the specifying of a section where a fault occurs even when an electric reception is made simultaneously from a plurality of lines by computing zero- phase components from data of currents and bus voltages in phases respectively to determine directions of faults in current detectors from a phase difference between both the results. CONSTITUTION:The newest data pertaining to a zero-phase voltage and a zero-phase current are stored into a memory 17 from a bus voltage transformer GPT and current detectors 9 and 10. An arithmetic section 18 reads a zero-phase current I01 from an addition circuit 14 from the memory 17 and when the current exceeds a fixed value, a phase difference is computed from a zero-phase voltage V0 read from the memory 17 as determined with an addition circuit 13. Direction of the current I01 is judged to be left when the current is the same in phase as the voltage V0 while to be right when it is opposite. Moreover, when each of breakers CB1 and CB2 makes, electric reception of one circuit is given from respective power source supply lines and when both the breakers make, electric reception of two circuits is given from both the lines. Hence, the type of condition is inputted. The arithmetic section 18 judges a fault section on specified conditions from above-mentioned information (presence and direction of zero-phase currents I01 and I02 determined from the detectors 9 and 10).

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a method for detecting which section of a plurality of sections divided by switching equipment the ground fault occurs in when a ground fault occurs in a substation. The present invention relates to a device for detecting whether or not a problem has occurred.

[Conventional technology]

FIG. 5 shows, for example, a conventional accident area 1m detection device of this type disclosed in Japanese Utility Model Application Publication No. 63-6361, which is installed in a gas-insulated substation. It is a circuit diagram showing what is applied to a leap device.

In the figure, (1), (2> and (3) are the first, second and third opening device elements as divided sections; ) and between the second and third switchgear elements (2) and (3) are connected by conductors (a) and (5) supported by insulating spacers IS and ■S2, respectively. IL and 2L4 . is the power supply line, and this gas-insulated switchgear is configured such that power is supplied to either line. CBI and CB2 are circuit breakers, DS, and DS2 are disconnectors, T H1~'I' lt 3 is a transformer, RyIIR3
'+2 is short cable protection relay, RY 21+ R5' 22
is ground fault protection relay, GPT is bus voltage transformer, c'r
, .

(i i'' is a current transformer inserted in each line nLL, 21-, and 14. Paralysis H2 is a magnetic field sensor installed in insulating spacer ■S1 and 182.

No. 61M is magnetic field sensor H,, H2 and each protection relay R3
/II~R1/2. This is an operating circuit for an accident area detection device that identifies an accident area from the output of the . That is, the magnetic field sensor H, is a conductor (4) supported by an insulating spacer ls+.
) and outputs a detection signal Sh1 proportional to the magnitude of the current. Similarly, the magnetic field sensor H2 outputs a detection signal sh proportional to the magnitude of the current flowing through the conductor (5).

Fault current detection signal generation port n(6) is short-circuited or grounded M1
Detection signal S h + or Sb captured when an N fault occurs
When either or both of them reach a predetermined level or higher, a fault current detection signal Sa or sb or both are generated. In addition, the short circuit protection relays Ry, and RyI2 detect the occurrence of a short circuit accident from the outputs of the bus voltage transformer GP T and the current transformers CT, CT2, and issue short circuit detection signals S, respectively.
Output H4 and S+2. Ground fault protection relay R5'2
1 and R3'22 similarly detect the occurrence of a ground fault and output ground fault detection signals Sol and S22, respectively.

Since the combination of generation of each detection signal Sa, Sb and S, I to S2□ differs depending on the section where a short circuit or ground fault has occurred, each judgment circuit (7a) (
7b) The section where the accident occurred can be specified by (8a>(8b)).

[Problems to be Solved by the Invention] The conventional accident section detection device is configured as described above, and according to the specified method, power is supplied from either line 1 or 21. If so, is it possible to identify the section where the accident occurred?
If the scope of application is expanded to include the case where power is simultaneously supplied from L, no matter which section an accident occurs, the fault current will flow from both lines 117 and 2L, and the output signal of magnetic field sensor H6゜1 (both 2) will be There was a problem in that this caused the accident area to become impossible to identify.

This invention was made to solve the problems mentioned above, and provides an accident section detection device that can identify the section where a ground fault has occurred even when power is being received from multiple lines at the same time. The purpose is to

[Means to solve the problem]

The accident section detection device according to the present invention includes a current detection device for detecting each phase current flowing between sections, and a current detection device for detecting each phase current flowing between sections,
a voltage detection device for detecting 11 voltage, a ground fault detection device for detecting a ground i1 fault occurring at the substation, a memory section for sequentially storing output signals from the current and voltage detection device for a predetermined period of time, and the ground fault. The operation is started by the ground fault detection signal of the detection device, and before the trilough operation based on the information of the auxiliary contact of the circuit breaker installed at the end of the power supply line of the above-mentioned substation and the above-mentioned ground fault detection No. 18 of the above-mentioned circuit breaker. The present invention is equipped with a calculation unit that specifies, by calculation, an area in which a ground fault has occurred from the information stored in the memory unit.

(Operation) The calculation unit calculates the zero phase portion of each phase based on the current and shore line voltage data read from the memory unit, determines the fault direction for each detection device from the phase difference between the two, and calculates the fault direction and the shoreline voltage. Based on the status of the power receiving line of the substation obtained from the auxiliary contact of the circuit breaker, the occurrence of the ground fault is determined by calculation.

〔Example〕

FIG. 1 is a circuit diagram showing a substation to which an accident section detection device according to an embodiment of the present invention is applied. In FIG. ) and the internal section tm (3) A current detection device that detects each phase current flowing between the internal section (tm), (10) is the internal section (
2) and the internal section (3), a current detection device for detecting each phase IC current flowing between the current transformer C'I' I
+ C'r2 and bus voltage transformer G as voltage detection device
Ground fault protection relay (12) is a ground fault detection device that detects ground faults that occur within the substation from the output of the PT.
C current detection device (9) (10), ground fault protection relay (11)
The fault section detection section identifies the internal section where the ground fault occurred based on the output information of the circuit breaker CB + and the information of the auxiliary contacts of the CH2, the details of which are shown in Figure 2.

In Figure 2, (13) is an adder 9 circuit that adds each phase bus voltage from the bus voltage transformer GP'1' to calculate the zero-phase voltage o, and similarly, (14) and (15) are respectively Adding each phase current from the current detection device (9) and (1 (J)) and flowing to the zero phase -. Addition circuit that calculates 1, 1°2,
(16) is the adder circuit (13>(14) which converts the output value from (15) into a digital signal A/l) 9 converter, (17) is the output signal from the A/' IJ converter (16) is sampled at a predetermined time interval and a fixed time '1
゛. (18) is a calculation unit whose operation will be explained in detail above, and (19) is a calculation unit (18).
This is an output display section that displays the results of detecting the accident section.

Next, the operation will be explained with reference to the timing chart of FIG. 3 and the flow chart of FIG. 4.

The memory section (17) always stores the latest data on the zero-sequence voltage and current from the bus voltage transformer G P ``f'' and the current detection devices (9) and (10) for time T0. As shown in Figure 3, if a one-wire ground fault occurs in the substation at time t1, the ground fault protection relay (11)
detects this and outputs a ground fault detection signal at time t2.

Upon receiving this signal, the calculation section 18) starts its operation, and the accident section detection section (12) including this calculation section (18)
Based on the above ground fault detection signal, the circuit breaker C
B1. (132 trips at time t. Therefore, the memory unit (17) stores data for '1' before this time t. For 12 hours, transient components consisting of current components and harmonic components are superimposed on the data, so remove this component <'r
, when fm ('I"1=Tl+1'2) (')
The above arithmetic processing is performed using the '7'-data.

First, the arithmetic unit (18) reads the zero-sequence current 1111 obtained by the adder circuit (4) from the memory unit (17), and determines whether or not this is above a certain level. If it is not above a certain level, it is assumed that no zero-sequence current is flowing, and the result is sent to a subsequent processing step. If the zero-sequence current is above a certain level.

Zero-sequence voltage ■ determined by the adder circuit (13) and read from the memory section (17). Which phase difference is calculated? Then, the direction of the zero-sequence current is determined by assuming that the direction of the zero-sequence current is to the left if it is in phase with the zero-sequence voltage, or to the right if it is in the opposite phase. , *lX is processed by adding circuit breaker auxiliary contact information to the information on the presence or absence of this zero-sequence current and the direction of the zero-sequence current.

This breaking 3 auxiliary contact information clarifies the conditions from the power receiving perspective of the substation at the time of occurrence of the ground fault accident, which is essential for analyzing the accident section. That is, blocking 3 CB 1
Person, CI (when 2 people are disconnected, 1 line power is received from the line IL; when the circuit breaker B1 is disconnected, CB, 1 line power is received from line 21 when there are people, and when the circuit breaker is CF31 and CB2, both lines are received) The type is tl as 2-line power reception from IL, 21-
The processing step for XlX identification is performed manually.

The calculation unit (18) determines the accident zone based on the above information based on the conditions shown in Tables 1 to 3 below.

Table 1 (for single line power reception from line IL) Table 2 (
Table 3 (In the case of 1-line power reception from line 21) (In the case of 2-line power reception from both lines 1 L 21-) However, in the above table, 1.1 indicates each phase current from the current detection device (9) The zero-sequence current found from ■. 2 is a current detection device (
10) Zero-sequence current obtained from each phase current, "-"
is a zero-sequence current or less than a certain level, and (left) and "right" indicate the direction of the zero-sequence current set corresponding to the phase difference between the zero-sequence current and the zero-sequence voltage described above.

According to the condition L:11-, it is determined by calculation whether the accident zone is present, the time is determined, and the result is displayed on the output display section (19).

According to this invention, it is possible to specify the fault section not only in the case of one-four-wire power reception but also in the case of two-line power reception. and,
After a ground fault occurs, the data stored in the memory section (17) is successively retrieved and subjected to arithmetic processing, so there is no need to process a large amount of data at high speed, and the arithmetic section (18) uses one microprocessor. It is inexpensive, and improves reliability and accuracy.

In addition, in the above embodiment, the power supply line of the substation or 211
! Although the case where two circuit breakers are provided for one line has been described, the present invention can be similarly applied to a case where the number of lines and the number of circuit breakers are further increased, and the same effect can be obtained.

Furthermore, the substation may be a gas insulated switchgear or the like not shown in FIG. Therefore, it is possible to identify the section where a ground fault has occurred regardless of the conditions related to the number of times the substation receives power, and the required calculations can be processed at low speed, improving reliability and accuracy, and making the equipment cheaper. .

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a substation to which a fault section detection device according to an embodiment of the present invention is applied, FIG. 21X1 is a block diagram showing the fault section detection section, and FIGS. FIG. 5 is a circuit diagram showing a cass insulation switchgear to which a conventional fault section detection device is applied, and FIG. 6 is a circuit diagram explaining the operation of the conventional device. In the figure, (1), ('2), and (3) are internal sections of the substation, ('J)<10) is a current detection device, (II) is a ground fault protection relay as a ground fault detection device, and (12) is the accident section detection section, (17) is the memory section, (18) is the calculation section, GPT
is a bus voltage transformer as a voltage detection device, LL, 21-
is the power supply line, CB. CB2 is a circuit breaker. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] For detecting the section where an earth fault occurred in a substation that is connected to multiple power supply lines and divided into multiple sections with switching equipment, detects each phase current flowing between the sections. A current detection device, a voltage detection device that detects each phase bus voltage of the substation, a ground fault detection device that detects a ground fault that occurs in the substation, and output signals from the current and voltage detection device for a predetermined period of time. A memory section that sequentially stores information, and information on an auxiliary contact of a circuit breaker that is activated by the ground fault detection signal of the ground fault detection device and is provided at the end of the power supply line of the substation, and the ground fault detection of the circuit breaker. 1. A fault section detection device for a substation, comprising a calculation section that specifies, by calculation, a section in which a ground fault has occurred from information stored in the memory section before the trip operation based on the signal.