JPS619121A - Parallel multichannel system ground-fault channel selective relay - 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 provides a high resistance
In particular, the present invention provides an excellent method for three-terminal systems.

In a parallel four-line system, depending on the system configuration, the mutual inductance between each phase of the system may be unbalanced, and an induced current (hereinafter referred to as circulating current) that circulates between the lines induced by the load current may occur.

In particular, the circulating current generated when one line is stopped, one line is stopped, and one terminal is open is significant and cannot be ignored compared to the fault current supplied from the neutral point resistor when one line is grounded. Therefore, the zero-sequence portion of the circulating current (hereinafter referred to as zero-sequence circulating current)
The relay tap value is increased to prevent the ground fault protection relay from malfunctioning. Therefore, there is a problem in that highly sensitive protection cannot be achieved as the zero-phase circulating current increases.

Line selection relay system to protect parallel 4-line circuits from ground faults 1 is - F 1 Solved the problem 0 mentioned above.
1, there are nine methods in which the constant zero-sequence current is stored and a faulty line is determined based on the change in the zero-sequence current at the time of a fault. However, in principle, this method responds to the change in zero-sequence current before and after a fault, so if an internal fault near the other end causes the other end to be cut off (series tripped), the zero-sequence circulating current will Because of this, it is difficult to identify the faulty line.For this reason, in the two-terminal, secondary system, after a certain period of time has elapsed after the fault occurs (the time before the other end is interrupted), the relay switches to the conventional line selection relay and detects the fault. A method is used to identify the line, but in a three-terminal system, the fault is removed by a three-stage series strip in which the other end experiences pre-cutting twice, so the above method cannot be expected to be sufficiently effective.

Another method is to calculate the zero-sequence circulating current by multiplying the measurable healthy phase circulating current by a vector constant (hereinafter referred to as a compensation constant) during a one-line ground fault, and then calculate the input current of the ground fault line selection relay. Since the inter-line zero-sequence difference current (hereinafter referred to as zero-sequence difference current) is a combination of the fault current and zero-sequence circulating current, subtracting the calculated value of the above zero-sequence circulating current from the zero-sequence difference current yields only the fault current component. There is a method in which the detected value is used as the new input current of the ground fault line selection relay to select the fault line. This method will be described in detail later on, but there is a problem that if there is a negative phase component in the load current, this will become an error current in the relay and reduce the detection sensitivity, and there is no way to solve this problem.

(Object of the Invention) An object of the present invention is to provide a ground fault line selection appliance that can reliably detect a ground fault line even in a high resistance grounded parallel 4-times II 3 terminal system in which a negative phase component exists in the load current.

(Summary of the Invention) The present invention subtracts an uncompensated value from the zero-sequence difference current between lines in a high-resistance grounded parallel multi-line system by excluding the positive phase component from the difference current between two phases of the line difference current. The first step is to find the value
a second means for determining the change in the load positive sequence current occurring in the inter-line difference current, and a third means for determining the direction of change in the load sum current occurring in the inter-line sum current. From to the first trip (first trip), the ground fault line is selected based on the amount of change and polarity before and after the occurrence of the ground fault with respect to the value obtained by the first means, and after the first trip, Value that cannot be obtained by the first method! and Jν
? The method is characterized in that the ground fault line is selected based on the polarity value and the difference between the sum and the estimated value obtained by the second means according to the direction of change obtained by the second means. be.

(Configuration of Embodiment) A ground fault line selector according to an embodiment of the present invention will be described below.

FIG. 1 shows the case where the present invention is applied to a parallel four-line three-terminal system. 11 to 16 indicate bus lines, 31 to 3
4 represents a power transmission line, and S and ~S represent electric stations.

The power transmission lines 31 to 34 from Sl to S are installed on the same tower. The power transmission lines 31 and 32 are at positions Pl*p
, and is configured as two parallel lines up to S3.

The power transmission lines 33 and 34 are configured as two parallel lines branching off from positions P8+P4 and ending at S4. Furthermore, the power transmission circuits 1fa33 and 34 are *tp, , p,! 6+″L
”CSs, Ss i ”RA*07m ””Ca1
l.

will be accomplished.

01 to 01G indicate the sections of the power transmission line, and their tower installation diagrams are shown in FIGS. 2(A) to 2(C). In this figure 2 a.

b and c indicate phases.Table 1 shows the results of the system simulation of the circulating current induced by the load current in the above system using a large-scale computer to determine the zero-sequence circulating current.

As the system simulation results show, the circulating current is proportional to the load current inducing it. Although this is confirmed theoretically, the properties of circulating current can be summarized as follows.

Margin below J) Properties L　a, b, C phase and zero phase circulating current Iae.

Ihc, Ice, Ioc are examples of the load current distribution that induces it.

Property 2 The proportionality constant is determined by the operating status of the parallel four-circuit system, its wire arrangement, and load current distribution.

Properties & Properties 1.2, zero-sequence circulating current I defined next
The vector ratio between oc and the amount obtained by excluding the positive phase component from the two phase circulating currents (also referred to as compensation instruction) is determined by the operating state of the parallel four-circuit system (its wire arrangement) and the load current distribution.

R (blank space below) Circulating current constants Km and Kb of each line obtained by performing system geonylation on the system configuration diagram in FIG.

The results of determining Ke are shown in Table 2.

(Left below) 1. Same as above, from the circulating current generated in the difference current between each line (the current required for the relay), for example between circuits 11i, 131 and 32, the vector ratio Ka, Kb defined in equation (1) is calculated.
.

This value for KO is also determined by the system operation status of the four parallel circuits (their wire arrangement) and their load current distribution.

First, I would like to briefly mention that this is one of the line selective relay systems that protect a parallel four-line system from ground faults using the conventional method.
There are some that have been made based on the properties (1) to (3) above.

I will discuss this in detail. A ground fault line selection relay that selects a ground fault line between lines 31 and 32 will be taken as an example.

When a single-wire ground fault occurs in phase a, the difference currents Ibd and Icd between phases B and C, which are healthy phases, between lines 31 and 32 do not include the fault current component, and are as follows. The difference current indicates the difference current between lines 31 and 32).

However, Ibe, IcL: B-phase and C-phase load currents (hereinafter referred to as load currents) generated in the difference current between lines 31 and 32.

Ibc, Ice: B-phase and C-phase circulating currents (hereinafter referred to as circulating currents) due to induction caused by the difference current between lines 31 and 32.

The load current is included in the difference current when there is a load at the branch end, or when the other end is ahead or cut off due to a system failure.

Further, the healthy phase difference current does not include a fault current component. (
2) Expressed by the load current components IbL, IeL, positive phase, and negative phase components LIL, IcL (assuming there is no zero-sequence component), however, 1. −;÷π1. −6j÷π.

In order to remove the influence of the positive phase component LL from this b-phase and C-phase difference current, the following calculation is performed.

・・・・・・・・・(4) Here, calculate the zero-sequence circulating current at the time of a-phase ground fault t
Therefore, the value of m shown in equation (1) and (Ibe-a in equation (4))
A = Ka (Ibd - aged) = roe
+ (a-1) KaI wealth L・river・song”・(
5) However, foe xKa (Ibc - alaa). This person is called the calculated value of the zero-phase circulating current.

Further, Ioa is referred to as operation Ioo. Similar calculations are used to calculate the ground faults of the B and C phases, as shown in Table 3 below.

Table 3 Next, the zero-sequence difference current 1od at the time of a one-wire ground fault is the fault current Iod
! x, +Ioa -・----(6) Of these, the zero-sequence circulating current Ioc included in the zero-sequence difference current Iod
Ninthly, the following calculation is performed using the above-mentioned calculated value At- of the zero-phase circulating current to find the relay input Iin.

11n=Iod-A=Iy+Ioc-(Ioa+(a-1)KaIgL)
=:=ry-(a 1)Kho'I*I, +jIoc
・・・・・・・・・(7) However, ΔIoc+=I
oc-Ioe ΔroC: Error Ioc In this way, in the conventional method, ΔroC is opposite to the load current.
Ioc is a constant Km in 5 columns, which will be explained later.
By setting the values of Kb and Ka, they can be made sufficiently small to be practically acceptable. but.

There is a problem in that the sensitivity of the ground fault line selection relay decreases due to the relay error current due to the negative phase component IIL of the load current.

An object of the present invention is to provide a line selection relay for a high-resistance grounded parallel 4-line 3-terminal system that is not affected by the circulating current induced by the load current and the negative phase component of the load current. The principle of the three-terminal system kM will be explained below.

Blanks Below (First Embodiment) A ground fault line selection relay determines a faulty line based on the magnitude and direction of the zero-sequence difference current between the lines at its own end (hereinafter referred to as zero-sequence difference current). Therefore, in the case of a fault near the other end, there is no zero-sequence current at the end of the eye until the other end is cut off in advance, resulting in a so-called series trip in which the other end is cut off first and the end of the eye is cut off. Figure 3 (Enter 1, fBl
, (C) is a diagram showing an example of the teno7 lease trip of the parallel four-time s3 terminal system. 1 is designated as an electric station 81. In the figure, 1 is the power supply, and 2 is the neutral point grounding resistance bjG.
R1411 to 444 are circuit breakers, and 82 to 8d are loads connected to the four mating buses 12 to 1B. The prisoner in the same picture is at the other end's electrical station 8. A ground fault occurred at the 310F point of the line near the
Indicates the case where this occurs. In this case, the ground fault line selection relays for lines 31 and 32 are activated, and the electrical station 88.8. ．． 8° times lol
The circuit breaker installed at A31 is tripped. Since the zero-sequence difference current between the current end and the other end electric station S, S, is close to zero, the line selection relay cannot respond.

When this occurs, as shown in FIG. 3 IBI, the breaker 412 at the other end is the first to cut off (or make the first trip). When the breaker 412 is opened, the zero-sequence difference current at the end and the opposite end increases, but the zero-sequence current at the other end carries the setting value of the ground fault relay, and the zero-sequence difference current at the own end carries the setting value of the ground fault relay. If the value is not exceeded, the breaker 413 at the other end is cut off (second trip) as shown in FIG. 3, 1cI.
. After that, although not shown, the fault current at the edge increases, and the ground fault line selection relay at the edge electric station 81 operates, and the breaker 41
1 trips and the fault is removed (third trip).

Considering such series tripping and excluding the influence of the negative sequence component of the load current, first obtain the relay input current by the following method until the other end is cut off in advance.

Electrical station 8 shown in Figure 3. If the negative phase component of the load current that appears in the differential current when the system is healthy due to the T-branch load of single-line power reception, which is the load of S6, is 12L, then the relay input current 1tn (hereinafter 1n) with which the zero-sequence circulating current is completely compensated is
is the relay input current with fully compensated zero-sequence circulating current. Setting Δ″X00=0 is obtained from the above equation (7) as follows:
)n. (However, 〒in + 12L means the amount when the system is healthy, and is the opposite phase component of the relay input current and load current before the one-phase ground fault.) Next, from the occurrence of the a-phase ground fault, the other end The input current 〒1n before cutting off is given by the formula (7).〒1n==IF+(a-1)Ka-LL "" (9
). 1# During a ground fault, it is impossible to measure the negative phase component of the load current from only the current at its own end, but in a high-resistance grounding system, the line voltage during a 1-wire ground fault is almost the same as when the system is healthy. Therefore, assuming that the magnitude of the T-branch load does not change before and after the occurrence of a ground fault, the negative phase component that appears in the differential current will also be kept at an approximately constant value before and after the ground fault (12
L=〒2L).

Therefore, if the change in the relay input current 11n before and after the occurrence of a ground fault is ΔIin, then from equations +81 and +91, we get:
"0 in l2L-i2L.

becomes. The calculated value ΔIin of equation [101] excludes the negative phase component and zero-sequence circulating current component of the load current, and contains only the fault current component. If this current Δ〒1n is newly set as the relay input current, a ground fault circuit can be determined.

1 (a = 1-73 Otsu 30°, Δ〒in stops by the change in the negative phase difference current.

Further, when Ka=0, Δ〒1n becomes a change in the zero-sequence difference current, but there is no relay error current in either case, and the relay performance remains unchanged.

By the above method, it is possible to exclude the influence W of the negative phase component of the load current until the opposite end is replaced (including external failures). However, as shown in Figure 3 IB), when the other end is cut off in advance at 'F', the load current generated in the difference circuit at the own end is large, and the reverse phase component of the load current appears in the difference current at the end. Since the change Δ〒2L before and after the occurrence of the ground fault does not become zero, (a −1)KaΔX2L in the C101 formula
remains as an error current in the relay input current. Therefore, after the other end is cut off in advance, the relay input current is obtained by the following method.

To explain this method in an easy-to-understand manner, we will first take the parallel two-line, two-terminal system shown in FIG. 4 as an example.

When the force of the load current is close to ioo%, the phase relationship between the positive phase component i1L of the load current and the fault current component IF with respect to the ground fault phase at the time of a one-line ground fault will be in-phase or anti-phase ( (See Figure 5 (C)).

In Figures 4 and 6 (C), solid line arrows indicate the direction of the load positive sequence current before the preceding trip, chain line arrows indicate the changing direction of the load positive sequence current after the preceding trip, and ■ indicates the direction of the load positive sequence current before the preceding trip. The positive direction is the same as the fault current direction that appears in the line difference current (difference between the zero-sequence currents of the lines 31 and 32) at the time of a fault, and θ indicates the reverse direction, which is the opposite direction. Also, -n
Δ11L represents a change in the load positive-sequence current applied to the relay input terminal, and n is a constant.

As shown in FIG. 4, the line 31 is connected to the electric station 8. When a failure occurs at point F in the vicinity of , the electric station BvO line selection relay operates first, causing the circuit breaker 412 to trip in advance. Then Figure 6 Prisoner~
Electrical station S as shown in icl.

Since the receiving power is a power current, the change ΔIll in the load positive sequence current caused in the line difference current is in the opposite direction, but Δ"X1Lt
- If it is detected and applied to the relay input terminal in the same direction as the fault current, the negative phase component of the load current is usually less than 5 to 10% of the positive phase component, so it will be affected by the negative phase component of the load current. It is possible to select a ground fault line without any problems. In a parallel 4-circuit, 3-leakage system, when one terminal trips in advance, the direction of change in the load positive sequence current that occurs in the differential current of the line selection relay installed line, which is the faulty line of the remaining 9 terminals, and the load positive sequence that occurs in the sum current. Tables 4 to 8 show the results of determining the direction of current change.
It is a table.

In Table 6 below, the positive phase' current is in the direction with respect to the ground fault phase (the same applies hereinafter), the same direction as the fault current appearing in the differential current e (E), and the opposite direction as ○.

However, the number of loaded power wheels is 1, and the same applies hereafter).

Tables 4 to 6 are as shown in the table, respectively.
6) to tEt in FIG.

In Figures B to G), all the changes from the busbar to the transmission line side are inward, and the opposite direction is outward (the same applies below).

4th table electrical station 8. If is the preceding trip, see Figure 6 (corresponding to the sword).
] Table 6 [The direction of the preceding trip is tidal current.

Table 7 [The direction of the preceding trip is the feed current.

Table 8 [When electric station S3 trips in advance.

Corresponds to Figure 6(E). ] However, the changes in fault current and load positive sequence current that occur in the differential current of the line with the line selection relay installed, which is a healthy line, are omitted because they are zero. Of these, Table 6 shows the case where the faulty line at electric station S2 was tripped in advance due to the power flow, and the changes in the load positive sequence current that appear in the differential current of the line where the line selection relay of the remaining terminal is installed and its direction are shown. Table 9 shows the amount of change in the load positive sequence current that appears in the sum current and its direction.

Table 9 Load shown in the differential current of the line selection relay installed line when one more terminal is cut off in advance and only one terminal remains The direction of change in positive sequence current and the load shown in the sum current Tables 10 to 12 show the results of determining the direction of change in the positive sequence current.

Table 10 [Remaining terminals are 8. In the case of the power transmission line 31. Corresponds to Figure 6 TFI. ] Table 11 [Remaining terminals are electrical station 8. transmission line 3]. Fig. 6 (corresponds to Gl). When the remaining terminal in Table 12 is the power transmission line 31 of electric station 8. Corresponds to Fig. 6 (H).] From the above, when a preceding trip is detected, the line selection relay, In order to operate correctly, for the zero-sequence difference current equation (7) that compensates for the zero-sequence circulating current, the direction of application of the change Δ11L in the load positive-sequence current appearing in the difference current is changed according to the direction of change in the sum current. and as shown in Table 13.

(Leaving space below) Table 13 Also shows the relay input terminal that takes the change before and after the ground fault (1@Formula There is also a method of applying the above ΔIsp according to the direction of change in the sum current, but it is not effective. There is the above method.

To cancel the relay error current due to the negative phase component of the load current 〒2L, the change in the load positive sequence current that appears in the differential current ΔI4L
is the phase current ΣAL1. of the line selection link-installed line for the relay input terminal equation (7). Spreading in the direction of change,■
Alternatively, apply in the O direction. However, electric stations 8. And for the line selection relay B4, Δ″X1L is always applied in the {circle around (2)} direction without detecting the changing direction of Σhi and L.

I in = rod −A :i:nΔ LL= I
y −(1-a)KalzL±, nΔIIL ・”9
Detecting the change in the load positive sequence current that appears in the °C difference current 1
For example, as shown in Table 14, a healthy phase current that does not include a fault current component is detected.

Table 14 Detection of Δ〒1L However, -'ad * Ibd+ red i as b*
C phase difference current.

11d/12d; Positive/negative phase difference current (based on ground fault phase)
.

Δ　1 Change before and after ground fault failure show.

Although the circulating current has a positive-sequence component, the amount of normal-sequence circulating current induced by the load current in the shared system is 6% or less, so Δ11L is detected by the above equation.

Similarly, the detection of the change in the load positive sequence current appearing in the sum current is as shown in Table 15.

1@z s However, rra* EZb*JTC1as b+ C phase sum current.

Σ Engineering 1. Σ12 t Positive sequence, negative sequence current.

Δ　Change before and after the ground fault.

The values of the constants Ka*ib and icc greatly influence the error LOc, Δroc, shown in equation (7), so setting these values is important.

However, Δroe + calculation error of zero-phase circulating current.

1 Indicates l+absolute IK.

However, since the constant Ka l Kb I Kc takes individual values depending on the system operation status as shown in Table 2, the constant is set to the constant Ka * Kb as follows to minimize the calculation error. Select r Kc f.

The current in each line of the relay installation terminal is measured and classified into several types of patterns depending on the magnitude of the effective portion relative to the reference voltage that does not change due to a one-wire ground fault and the condition of no current, and the corresponding pattern is determined for each individual pattern. Constants IC"', K"' that minimize the calculation error of the zero-phase circulation α9 flow that occurs under the system operating conditions.

a b K, gold, is determined in advance from the simini region of the strain in question. Other means are shown below.

(Second Example) The relay input terminal eQI formula from the occurrence of a failure to the first trip is the change in the negative phase difference current with Ka: 1.73,430°, and after the second trip, the line selection relay is The direction of change of the positive sequence component of the sum current of the installed circuit (depending on the direction of change of the positive sequence current of the difference current, apply it in the same direction or in the opposite direction,
Select the ground fault line without being influenced by the circulating current and the negative phase component of the load current.

(Third embodiment) Relay input terminal 'tIl from failure occurrence to first trip
In Equation 1, the change in the zero-sequence difference current with Ka = 0 is taken as the change in the zero-sequence difference current, and from the second trip onward, depending on the direction of change in the positive-sequence phase current of the line where the line selection relay is installed, is the positive-sequence of the difference current. The current change is set in the same direction or in the opposite direction, and the ground fault circuit is selected without being influenced by the influence of the circulating current and load current reverse phase components.

(Fourth embodiment) Relay input terminal 't-1 from failure occurrence to first trip
In formula 101, Ka = L73 O 30 degrees or zero, and from the second trip onwards, the difference will be calculated depending on the direction of change of the positive phase component of the sum current of the line where the line selection relay is installed for the negative phase difference current or zero phase difference current. The positive sequence current change portion of the current is applied in the same direction or in the opposite direction, and the ground fault line is selected without being influenced by the influence of the circulating '1 current and the negative sequence component of the load current.

Among the inventions described above, Example 1 is the most effective.

A first embodiment of the present invention will be described in more detail.

FIG. 7 shows an embodiment of a parallel four-line three-terminal system. Although the power transmission line has a two-terminal configuration to simplify the drawing, there is no difference between the embodiments even if the power transmission line has a three-terminal configuration. The earth fault protection relay according to the present invention is installed at the electrical station 81°S, , S, and B4 ends, and the line selection relay is installed at the terminals 31.32 and 33.3 of the electric station.
It will be installed at 4. In Figure 7, 1a-1c are three-phase power supplies, 2
are neutral grounding resistors N()R, 1la-11c and 12
a-12c shows the bus line, 31a-34c shows the power transmission (line), of which 31832 and 33.34 are No. 1 (
IL), No. 2 (2L), No. 3 (3L), and No. 4 (4L) lines. Also, 3 is a transformation for voltage detection.

A Hb @ C phase voltage P 1 (w
a *Eb, PC) Zero-sequence' voltage E. Detect. 41
1a-411c indicates a circuit breaker. 51a-54c indicate current transformers for current detection, and power transmission lines IL, 2L.

IL IL 3L, 4L a @ bg C and zero-sequence current 1 (
1.

Shou L IL Yui L j? L
2L 2L 2L 2Lx
,1 ,r ),I (1,II, ,I
. , Eng. ), b c O BL ILL ILL Sumi L Crystal L AL
4L AILI (I, I II,
r), 1 (1, I.

a b a Oa
B Engineering 4LI T4L) is detected. 8. indicates the opposite end electric station, and 82 indicates a three-phase load.

First, electric station 8. The ground fault line selection relay for selecting the line 31.320 ground fault circuit M will be described with reference to FIG.

4 denotes a first data converter, and "IL'2" of each line of the analog quantity detected by the current transformers 51a to 54c.
L "ILL 'AL Each phase current DI (I +
X + X + Reference numeral 3 in FIG. 7 is a voltage detection section, which is composed of a phase voltage detection transformer, which is a first voltage detection section, connected to the bus 11, and a zero-phase voltage detection transformer, which is a second voltage detection section. . Reference numeral 6 indicates a second data converter, in which the analog quantity a detected by the voltage detection unit 3,
The b and c phase voltages Ha, ib, Me (D,) and zero-sequence voltage io (DI) are A/D converted to digital quantities Ds (Ba Iieb * Ec) and (÷
0) t-output.

6 is a first filter section, which inputs the digital quantity of the output D4 (a, b, c phase current of each line) of the first data converter 4 and selects the lines 31 and 32 where the line selection relay is installed.
The difference current between the two phases is calculated, the positive phase component is excluded from the line difference current of the two phases, and the difference current is outputted as Dat. The digital quantity Ds consists of the following three quantities.

7 is the compensation constant setting section, which is the output D of the data converter gain.
4 (a, h, and c phase currents of each line) and the output voltage of the second data converter 5 (each phase voltage of the bus line),
They are classified into several types depending on the magnitude of the effective component of each line IE current with respect to a reference voltage (line voltage) that does not change due to a one-line ground fault, and the condition of no current. For each individual baton, constants Ka and Kb that minimize the calculation error of the zero-sequence circulating current generated for the corresponding system conditions are set.
, EcK, constants Ka, Kb, Kc, Kfx b, calculated in advance and selected according to Batan classification.
D o t - Output Thru.

8 is a first calculating section, which calculates the calculated value D of the zero-phase circulating current from the output of the first filter section 6 and the output of the setting section 7.
Ask for IG. This calculation value is . are the following three calculated values.

Reference numeral 9 denotes a second calculation unit, which outputs the output D4 of the first data conversion unit 4 and the output D14 of the ground fault detection unit 12, which will be described later.
Input k to find the change I)it in the load positive sequence current before and after the ground fault failure, which appears in the differential current of the line where the line selection relay is installed. I) ts are the three quantities shown in Table 13.

Reference numeral 10 denotes a third calculation unit, which outputs the output D4 of the first data conversion unit 4 and the output Dwat of the ground fault detection unit 12, which will be described later.
- Manually find the change D1'*t'' in the load positive sequence current before and after the ground fault, which appears in the sum current of the line where the line selection relay is installed.Dl is the three quantities shown in Table 14.

Reference numeral 11 denotes a ground fault phase detection unit, which determines the ground fault phase when a one-wire ground fault occurs. □To give one example, the digital quantities of a + b #, which is the output D6 of the second data converter 6, and the C phase' voltage are input and the following calculation is performed.

However, lIi! +2 is the square of the absolute value is a scalar coefficient.Furthermore, the ground fault phase detection unit 11 determines the ground fault phase from the above-mentioned L1 to L6 using the determination formula shown in Table 18 below, and determines the ground fault phase at the time of a 1m ground fault. Outputs a discrimination signal DIM.

Its characteristics are shown in Figure 9.

Table 16 shows the ground fault detection section.One example is the output of the second data conversion section 5, that is, the digital quantity of the zero-sequence voltage is input, and the magnitude thereof exceeds a certain value. A ground fault is detected by the ground fault, and a ground fault fault detection signal D14 is output.

13 is a first selection unit which inputs the discrimination signal I)ti of the p1 ground fault phase detection unit 11 and the calculated value D1° of the first calculation unit 8;
The calculated value D'**t- of the divided zero-phase circulating current at the time of a ground fault in one line of the system is selected by the ground fault phase discrimination signal D□.

14 is the fourth arithmetic unit, and the system 1'? m At the time of a ground fault - Calculate the input current ΔIin t of the line selection ground fault relay from the occurrence of the fault to the preceding trip on the other end. This calculation section 14
The calculation value of the zero-sequence circulating current at the time of a ground fault in the system IM, which becomes the output Dll of the selection unit 13, and the digital amount of the zero-sequence current of each line, which becomes the output of the first data conversion unit 4, and By inputting the ground fault detection signal that becomes the output I)ta of the ground fault detection unit 12, the calculated value ΔIt''(Dta
) Output k. That is, the zero-sequence difference current Iod f of the line where the line selection relay is installed is calculated from the zero-sequence current of each line, the calculated value A of the zero-sequence circulating current is subtracted from this, and the occurrence of a ground fault is detected by the signal D14 for that value, and the
(The change amount ΔIin t- before and after the occurrence of the ground fault shown in equation 1)
Calculate and output ・Also, the value shown in equation (7), that is, the value DI? which is obtained by subtracting the calculated value of the zero-sequence circulating current from the zero-sequence difference current Iod? Output.

Reference numeral 15 denotes a second selection section, which inputs the ground fault phase discrimination signal Dts and the calculated value D1g of the calculation section 9, and selects the ground fault phase discrimination signal 8.
．． The output Dla is set to the value selected according to the change in load positive sequence current ΔILL t shown in the difference current at the time of a ground fault in one line of the system as shown in Table 14.

1B is a third selection section, which inputs the ground fault phase discrimination signal D1M and the calculated value of the calculation section 10, and receives the ground fault phase discrimination signal I)
Let the output I)to be the generally selected value of the load positive sequence current change Δi,L, which appears in the sum current at the time of a single line ground fault in the system due to sm, in Table 16.

Reference numeral 17 is a preceding trip detection section at the other end, which is the change ΔIt1. in the load positive sequence current before and after the occurrence of a failure, which is represented by the difference current that becomes the output D1g of the selection section 15. e is input, and if this absolute value is greater than a certain value, it is determined that there is a preceding trip at the other end and a signal Dsxk is output, and when the absolute value is less than a certain value and it is determined that there is no preceding trip at the other end, a signal is output. Full output.

Reference numeral 18 denotes a first ground fault line selection section, which calculates the digital quantity of ΔItn(LL (see equation 1), which becomes the output I)ts of the calculation section 14, and the zero-sequence voltage VO, which becomes the output D7 of the data conversion section 6. , the output I) of the opposite end advance trip detection section 17 and the other end advance trip no signal which becomes to are input, and the ground fault line is selected until the period when there is a system 1 line ground fault and the other end is not tripped in advance. Ground fault line discrimination signal D*z*D
Output tsk. In this selection unit 18, the relay input terminal during the period from when a ground fault occurs until the other end trips in advance becomes DI6, which is the input from the calculation unit 14.
It is iin.

As an example, a ground fault line is determined based on the following (g): From equation 09, the effective part of Δrin as a zero-sequence voltage vo bipolar voltage is greater than or equal to a certain value ±ε or less.

However, (△Itn-÷O) is the vector inner product value, 1÷01
indicates the absolute value. The nib selection unit 18 detects a ground fault in the line 31 and α9 when this formula is established.
If the formula holds, it is determined that there is a ground fault in the line 32, and if there is a ground fault in the line 31, a ground fault line discrimination signal is issued. ft is output, and a discrimination signal D□ is output in the case of a ground fault at times @32.

50 is an electrical station 81 and 8. It is the second ground fault line selection section, and the output of the calculation section 14 is blue (see equation (7)) and 1.
．． The output of the data converter 18 is the zero-sequence voltage divided by 0, and the output I) of the arithmetic unit 16 is Δil, which is the output I)ta.
Input L and the output I) of the calculation unit 18, ΣΔTE, which becomes 1o, L and the other end pre-shutoff signal, which becomes the output pat of the detection part 17. After selecting the ground fault line, the ground fault line discrimination signal Dt
4 and Dta'e are output. In this selection section 19, similarly to the selection section 18, when a ground fault occurs, the relay input current of the preceding breaker at the other end changes from the values in Table 14 to those in Table 17.

Table 17 However, n: Constant Earth fault line discrimination is performed using formula 09 (a), and in the case of the ground fault in circuit M31, the ground fault line discrimination signal D*at- is output, and in the case of the ground fault in circuit A32, the ground fault line is discriminated. Output the signal I)ms.

Among the outputs of these selection units 18 and 19, the ground fault line discrimination signal D! of circuit M31 is selected. * * Dt4 is the logical sum of the OR gate 21 and the trip command p for the circuit breaker of the line 31, ? The ground fault line discrimination signal D! of circuit R32 is assumed to be !
Il and D□ are logically summed by the OR gate 22 and used as a trip command S□ for the circuit breaker of the line 32.

Electrical station8. As for the line selection ground fault IJ V- of B4 and B4, as shown by the broken line block,
0 and and gate! Prepare 23.24. During this block, the off-delay timer unit 90 receives as input the signal indicating that the other end has pre-shutoff, which is the output Dtt of the other end advance trip detection unit 17, and after a certain period of time from the input of the signal Dll (of the line selection ground fault relay). The ON signal D*a'e' is output during the phase corresponding to the operating time and the breaker operating time). The AND gates 23 and 24 are the output 1)m of the off-delay timer section 20.
The outputs of the OR gates 21 and 22 are set as a new trip command (D2J) for the line 31 and a new trip command (Dti) for the line 32, respectively, on the condition that s is satisfied.

However, the change in the load positive sequence current that occurs in the sum current, ΣΔ′X
Since there is no need to detect 1L, the arithmetic unit 10 and selection unit 181 are omitted.

Further, the change ΔILL in the load positive sequence current that occurs in the difference current in the selection unit 19 is applied in the e direction.

(The following is a blank space) (Effects of the invention) As explained above, in the present invention, the positive phase component is excluded from the difference current between two phases of the line current in a high-resistance grounded parallel multi-circuit system by the first means. The value compensated for the amount is subtracted from the inter-line zero-sequence difference current, and the direction of change in the load sum current generated in the inter-line current is determined by the second means. A ground fault line is selected based on the amount of change and polarity before and after the occurrence of a ground fault with respect to the value obtained by the first means, and up to the first trip, the value obtained by the first means and the third Since the ground fault line is selected based on the polarity and the sum or difference of the value obtained by the second means in accordance with the direction of change obtained by the second means, the load current has a negative phase component. It is possible to obtain a high-performance ground fault line selector that can reliably detect a ground fault line even in the existing high resistance ground system parallel four line terminal system.

[Brief explanation of drawings]

Fig. 1 is a parallel four-circuit power transmission system diagram, Fig. 2 (6) to C) is a wire layout diagram, and Fig. 3 (4) to C) and Fig. 4 are ground fault line selection according to the embodiment of the present invention. An explanatory diagram of the operation of the device, Fig. 5 (
4) is a current vector diagram at the own end when the other end is cut off first, FIG. 5 (B) is a current vector diagram at the end when the other end is cut off first, and FIGS. FIG. 7 is an electrical wiring diagram of the ground fault line selector according to the embodiment of the present invention, FIG. 8 is a block wiring diagram thereof, and FIG. FIG. 3 is a diagram showing entangled phase discrimination characteristics. 11-16... Bus bar, 31-35... Power transmission line, 4
... first data conversion section, 5 ... second data conversion section, 6 ... first filter section, 8 ... first calculation section, 9 ... second calculation section , lO...Third calculation unit, 1
1... Ground fault detection section, 12... Ground fault detection section, 13
...first selection section, 14...fourth calculation section, 15.
...Third calculation section, 16...Third selection section, 17...
- Opposite end advance trip detection unit, 18... first ground fault line selection unit, 19... 20th ground fault line selection unit, addition...
Off-delay timer part, 21.22...or gate, feather, 24...and gate. Figure 3 CB) To Figure 3) Figure 4 Figure 5 (B) Figure 5 (C) Figure 6' (A) Figure 6 (C) Figure 6 (E) S3 Figure 6 CF) Figure 6 (G) Procedural amendment export) 1. Display of the case 1983 Patent Application No. 28659 2, Name of the invention Ground fault line selection relay for parallel multi-line system 3, Person making the amendment Relationship to the case Applicant Shikoku Electric Power Co., Ltd. ($10) Iyoro Meidensha 4, Agent Address: 1-29 Akashi-cho, Chuo-ku, Tokyo 104, Japan Liquor Manufacturing Co., Ltd. Claims a Contents of amendments
Amend the claims by attaching a separate sheet. [Attachment] Claims (1) A value obtained by excluding the positive phase component from the difference current between two phases of the difference current between lines of a high-resistance grounding system parallel multi-circuit and multiplying it by a coefficient is subtracted from the zero-sequence difference current between lines. a first means, a second means for determining a change in the positive sequence current occurring in the inter-line difference current, and an eighth means for determining the direction of change in the sum current occurring in the inter-line sum current; a first selection means for selecting a ground fault line based on the amount of change and polarity before and after the occurrence of a ground fault fault with respect to the value obtained by the first means from the occurrence of the fault until the first trip; After the trip, the value obtained by taking the sum or difference between the value obtained by the first means and the value obtained by the second means according to the direction of change obtained by the eighth means, and the polarity amount. and a second selection means for selecting a ground fault line based on the following. (2) The value obtained by the first method by checking the operation of the relay for a certain period of time after the first trip, and the value obtained by the second method.
The first claim is characterized in that the ground fault line is selected based on the sum of the values obtained by the method and the amount of polarity.
Ground-fault line selection relay for parallel multi-line systems as described in . (3) A ground fault line selection relay for a parallel multi-circuit system according to claim 1, wherein the value obtained by the first means is the change in the negative phase difference current before and after the ground fault. (4) A ground fault line selection relay for a parallel multi-circuit system according to claim 1, wherein the value obtained by the first means is the change in zero-sequence difference current before and after the ground fault. (5) A ground fault line selection relay for a parallel multi-circuit system according to claim 1, characterized in that the value determined by the first means is a negative phase or zero phase difference current. Procedural Amendment Act 1982 Patent Application No. 28659 2 Title of Invention Ground Fault Line Selection Relay for Parallel Multiline System 4 Agent Address: 1-29A Akashi-cho, Chuo-ku, Tokyo 104; Suiseikai Building 1986 Column for brief explanation of drawings subject to June 25, 2015 a amendment
Specification of Guar Correction, page 58, line 10 [Figure 6 (A) - K before (smell) [Figure 5 (0) is the current vector in the tidal flow when the partner power supply terminal is cut off first] Figure, insert all. on υ

Claims (5)

[Claims] (1) A first means of calculating the value obtained by subtracting the value compensated for the amount obtained by excluding the positive phase component from the difference current between two phases of the difference current between lines of a high-resistance grounded parallel multi-circuit line from the zero-phase difference current between lines. and a second means for determining the change in the load positive sequence current that occurs in the inter-line difference current, and a third means for determining the direction of change in the load sum current that occurs in the inter-line sum current. a first selection means for selecting a ground fault line based on the amount of change before and after the occurrence of a ground fault fault and the amount of polarity with respect to the value obtained by the first means until the first trip; After the first trip, the sum of the value obtained by the first means and the value obtained by the second means depending on the direction of change obtained by the third means, or 1. A ground-fault line selection relay for a parallel multi-line system, characterized by comprising second selection means for selecting a ground-fault line based on the difference value and polarity. (2) After the first trip, the operation of the relay is locked for a certain period of time, and the polarity is the sum of the value obtained by the first means and the value obtained by the second means. A ground fault line selection relay for a parallel multi-circuit system according to claim 1, characterized in that the ground fault line is selected accordingly. (3) A ground fault line selection relay for a parallel multi-circuit system according to claim 1, wherein the value obtained by the first means is the change in the negative phase difference current before and after the ground fault. (4) A ground fault line selection relay for a parallel multi-circuit system according to claim 1, wherein the value determined by the first means is the change in zero-sequence difference current before and after the ground fault. (5) A ground fault line selection relay for a parallel multi-circuit system according to claim 1, wherein the value determined by the first means is a negative phase or zero phase difference current.