JPS59178921A - Ground-fault selecting relay for common trestle multichannelsystem - 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 The present invention relates to a ground fault line selection relay for a shared multi-line system.

In a shared multi-circuit transmission line in which many transmission lines are co-extended on the same tower, the mutual inductance between each conductor of the transmission line is unbalanced, and the fault current of other lines (hereinafter referred to as MA) A zero-phase current (hereinafter referred to as zero-phase OC) circulates between the lines of the induced system due to the induction of the load current. If the induced system is a high resistance grounding system, the current capacity of the neutral point resistor is generally 100A ~
400A/25, and since the zero-phase circulation subcircuit OC becomes negligibly large for 1jjQ, it is difficult to provide highly sensitive and reliable ground fault protection. As a countermeasure against this problem, there has conventionally been the following system as a ground fault line selection relay that protects two parallel lines of a shared multi-line high resistance grounding system from ground fault failures.

A zero-phase circulating subcurrent is calculated by multiplying the measurable healthy phase circulating current at the time of a one-wire ground fault by a vector constant (hereinafter referred to as a compensation constant). Next, the line-to-line zero-sequence difference current c (hereinafter referred to as zero-sequence difference current), which is the input current of the ground fault line selection relay, is a combination of the fault current and the zero-sequence circulating current, and the above zero-sequence circulating current can be calculated from the zero-sequence difference current. By subtracting the value and detecting only the fault current component, and using this detected value as the new input current of the ground fault line selection relay, the fault line is selected without engravings caused by zero-phase circulating current. This conventional method will be described in detail later, but
If there is a negative phase component in the load current, there is a problem in that this becomes a residual frost, an error current of 5, and lowers the detection sensitivity.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ground fault line selection appliance for a shared multi-line system that can reliably detect a ground fault phase even when a reverse phase component exists in the load current.

The present invention will be described in detail below, including the problems of the conventional method.

There is a slight change in the ring current VC of the shared multi-circuit system.

Property 1...The inter-line a, , b, C phase and zero-phase circulating currents generated in the induced system due to the induction of the load current in the induced system are ac, from c, ICc, and OC (
The circulating current (hereinafter referred to as circulating current) is proportional to the load current of the induction system, and its proportionality constant is determined from the wire arrangement and wire thickness of the shared multi-circuit system and the operational status of the induction system.

Property 2: Under the zero-sequence circulating current defined by the following equation (1)
The vector constants (compensation constants) Ka, Kb, Kc are the ratio between c and the firefly obtained by excluding the positive phase component from the two sets of phase circulating currents.
As is clear from the above property, it is determined from the wire arrangement and wire thickness of the shared multi-circuit system, and the operational status of the induction system, regardless of the thickness and phase of the load current in the induction system. Ru.

However, a, -εj7d7r The above-mentioned compensation constants Ka, Kb, and Kc are as shown in Table 1 below in the ultra-high pressure shared system shown in FIG.

Figure 1 shows a power transmission system in which two parallel ultra-high voltage system lines 1 and 2 and clear grounding system lines 3 and 4 are co-extended on a steel tower 5, with ultra-high voltage system lines IA~IC and 2A~ 2C has a reverse phase arrangement, and high resistance grounding system pillow circuits 3a to 3C with in-phase arrangement.
In the lines 111 between and 4a to 4C, a constant current is generated due to the induction of the load current of the super high voltage system (super induction system). In addition, A.

B, C and a, b, c (indicate the phase, W, W',
D.

"A, σ, and H indicate the wire arrangement, w=6m.

W'=8m, D-8m, ff=8.5m,
d=3m, H=20m. ′! 1, 2 are 610111! There are 44 bodies, 610 lines 3.4, and 4 AI bodies.

In the ultra-high pressure shared system illustrated in Fig. 1, the guided system 1
When a line ground fault occurs, for example, an A-phase ground fault, the C phase becomes a healthy phase of the induced system, and the C phase circulation difference 'torque current (hereinafter referred to as difference current) cl, ■cd, however, From c, I
Cc is L from the circulating current of C phase and C phase; , OL is C
The fault current component (1) is not included in the healthy phase difference current.In this equation (2), from the load current component, This is generated by the T-branch load of the positive phase and negative phase components ab
, expressed in terms of 2L (assuming there is no zero-sequence component), Equation (2) becomes ``1. However, a..., a-・j÷''. From this C-phase and C-phase difference current, the positive Eliminate the influence of phase component engineering IL/8: Do the following demonstration.

Ibd −aICd = (I'bc + a2I+
t, + a Engineering 2L ) - a ( Engineering CC + a Engineering IL +
a2■2L)=(more c-aIcc)-1-(a
-1) J-2L・・・・・・・・・(4) Here, calculate the zero-sequence circulating current at the time of C-phase ground fault. In order to do this, Ka of the equation (]) and (from c −aICd of the equation (4)
) and 4i[.

The calculated value A is A = Ka (Ibd - aICd) = Ka (
(I'bc -aC(3)+(a4)I2L)
= ko oc + (a-1) Ka ko 2 t, -・-
(5J. This A is called the calculated value of the zero-sequence circulating current by the positive-sequence exclusion method. It can be obtained by the same operation when the B-phase and C-phase ground faults occur, and as shown in Table 2 below. Become.

Table 2 Next, the zero-sequence difference current Iod when one wire is grounded is fault 147. It is the sum of current Iy and zero-phase circulating current work ○C, and work Od - work F
Juko OC・・・・・・(6) Of these, zero-sequence difference current Io
In order to compensate for the zero-sequence circulating current Ioc included in cl, the following calculation is performed using the above-mentioned initial value A of the zero-sequence circulating current to obtain the relay input Iin.

l1n-work od -A = IF 10 work oc- (work oc+ (a -1) Ka, work 2L+ = 1F - (a -1) Ka work 2 L = -
=-...- (7) In this way, in the conventional method, if the load current does not have the negative phase component 2L, the fault 'Kameho F component will be damaged by the calculation of equation (7) above. If the input current of the ground fault line selection relay is not detected,
If so, even if the zero-sequence circulating current is large, it is possible to correctly detect a ground fault in the 1st line.However, if there is a negative sequence component in the load current or current, an error current component will be added to the input of the device. The present invention excludes the influence of the negative phase component of the load current,
This is intended to be applied to a three-terminal system, and the principle will be explained below.

A ground fault line selection switch identifies a faulty line based on the magnitude and direction of the zero-sequence difference current (hereinafter referred to as zero-sequence difference current) between the lines at its own end. Therefore, in the case of a fault near the other end, there is no zero-sequence difference current at the own end until the other end is cut off in advance, resulting in a so-called Series 7 trip in which the other end is cut off first and the own end is cut off. Figure 2 (a), (b)
, (0) is a diagram showing an example of Series 7 trip in a parallel two-time m3 terminal system. In the figure, 6a to 6f are circuit breakers, and 7a and 7b.

7C is the electric station busbar of the own end and each other end, 8 is the power supply,
9a is the T-branch load of line 3, 9b and 9c are the opposite end motherboard #7
'b, shows the load connected to 7c.

Figure (a) shows a case where a ground fault occurs at point F near the other end, and the line selection relay cannot respond because the zero-sequence difference current between the end and the other end is close to zero. For this reason, Figure 2 (
As shown in (to), the first trip (or first trip) is made by the breaker 6C at the other end. When the breaker 6C opens, the flow increases due to the zero phase difference between the own end and the opposite end, but the zero phase difference flow at the opposite end exceeds the set value of the earth fault joint, and the zero phase difference at the own end increases. If the current does not exceed the set value of the earth fault relay, the breaker 6e at the other end is disconnected (second trip) as shown in FIG. 2(C). Thereafter, although not shown, the ground fault joint at its own end operates and the fault is removed (third trick)').

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.

If the negative phase component of the load current that appears in the differential current due to the T-branch load shown in Figure 2 when the system is healthy is 2L, then the zero-sequence circulating current is completely compensated for 1 * city 1 unit input current in
(Hereinafter, Iin is the relay input current for which the zero-sequence circulating current is completely compensated.) is the formula (7) above, % (8). However, Iin and I2L are system M, and - when in good condition.
It means relay input current before a phase ground fault and negative? f!
r is the negative phase component of the current.

Next, the input current 1n at the time of a phase ground fault and before the other end is cut off first is calculated by equation (7):
−I2L −−−−−=−(97) It is impossible to measure the negative phase component of the load current from the current at the end of the eye when a one wire ground fault occurs, but in a high resistance grounding system, one wire ground fault The line voltage during this time is almost the same as when the system is healthy, so
Assuming that the magnitude of the T-branch load does not change when the ground fault occurs, the negative phase component appearing in the differential current will also be kept at a nearly constant value before and after the ground fault (I2L = 2
L).

Therefore, if the change in relay input current in before and after the occurrence of a ground fault is △Iin, then from equations (8) and (9), △work j
-n=]In -l1n =Iy+(a-1) Kazt, -(a-1)KaIz
b = engineering p + (a-1) KaΔ engineering 2L #■F
・・・・・・・・・(101 iris, △work 2L=work 2L - work 2L key 0.

becomes. This calculated value △workin of equation 1 (9) excludes the negative phase component and zero-sequence circulating current component of the load current, and becomes only the fault current component.This current △workin is newly calculated as the relay input current. If so, you can identify the ground fault line.

By the above method, it is possible to exclude the influence of the negative phase component of the load current before the other end is cut off (including external failures). However, if the other end of VC1 is cut off in advance as shown in 2nd [1(b)], the line impedance of the two parallel lines becomes unbalanced, and the load current generated in the difference circuit at its own end changes greatly, and the The change ∆2L before and after the occurrence of a ground fault fault due to the load current that appears in the differential current does not become zero and becomes 0.
(a-1) KaΔme2L in equation 0 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. If the power factor of the load current and current is close to 100 ( The phase relationship between the positive phase component IL of the load current and the fault current component IF is in phase or in opposite phase.3
In a terminal system (1 source terminal, 2 load terminals), if the other end is leading or lei l, the difference between the own end is 11 loads, which are held at the end, and the flow) E phase change. The direction is shown in Table 3 below, which corresponds to the figure 3 shown in Figure 3 for the first cutoff and pre-excitation of the cutoff by drawing the ground fault occurrence position. Both terminals are in the same direction (■) with respect to the faulty line. The vector diagram is shown in FIG. 4(a). Further, if the load end is the first in the state of power flow and is broken, both the load end and the R1 end of the mating terminal will have an opposite force direction O with respect to the faulty line. The vector diagram is shown in Figure 4(b).
Shown below. Figure 4 (a), (b) middle, standing.

Eb, 12:c is a, 'b, c phase voltage, -
Vo (zero-sequence voltage at the time of a phase ground fault, △IIL is the change in the positive phase portion of the load current when the other end is cut off in advance, and C
Figures (a+, (b).

(c) Inside, solid arrows indicate circuit breaker 6a, 6'b
, 6 The load current direction of the line 3 before C is opened, and the dashed arrow indicates the load current, current, and change direction of the line after the breaker is opened.

From Table 3 above, (with respect to the relay input current △Iin of formula 101, M, which is proportional to the change in the flow pressure phase between the loads and the current pressure phase that appears in the differential current at its own end when the other end is cut off in advance, is As shown in Table 4 below, the power supply end relay is connected to the relay.

If -nΔwork+t is added to the load end relay, the failure M current can be obtained.] Since the workpiece F and the deltaworkIL are in the same direction, it is possible to correctly determine the faulty line even if there is a reverse phase component of the load current.

Table 4: Constant However, as shown in Fig. 5, if the load end 7c is cut off first (first lip), the load end relay at the other end will have a failure as shown in Fig. 4 (to). Since the positive phase change ΔtL of the load current is applied at the opposite position to the current IF, there is a risk of malfunction or malfunction. Therefore, when the first trip (earliest cutoff) is detected only in the load end relay (the detection method will be described later), the operation is delayed by a timer until the power end trip (second trip). On the other hand, the power supply end relay is not necessary because the change in the positive phase portion of the load current Δwork IL applied to the faulty current switch F operates in a positive direction because it operates in four directions. When the second trip is caused by the power supply terminal relay, the load terminal relay operates normally because the fault @ machining F and the load current positive phase change △ machining IL are in the same direction (
(See Figure 4a).

With the above method, it is possible to correctly select a faulty line without being affected by the zero-sequence circulating current or the load current, but for this purpose it is necessary to detect the positive-sequence component of the load current. The method will be explained below.

In addition to properties 1 and 2 described above, the following property 3 exists as a matter of circulating current.

Compensation constant 1x, Ll) defined by the following equation υ.

LC is unrelated to the thickness and phase of the power flow of the originating G24 system, and is determined by the wire arrangement, the thickness of the short wires, and the operational status of the originating and guiding system.

However, the results of determining the compensation constants La, Lb, and Lc using the circulating current calculated from the wire arrangement shown in Figure 1 are shown in the fifth column.
Shown in the table.

Table 5 When the b-phase and C-phase difference currents Ibd and Icd of healthy phases are measured when a C-phase ground fault occurs in the induced system, the above equation q(3) is obtained. Delay C phase difference current Icd by 1200 to obtain b phase difference current Ib
When subtracted from d, the negative phase component is removed and the following equation (2) is obtained.

■ bσ - a2 ■ c (1 = (from c + a2 engineering + L + a
I2L)-a2(Icc+a-IL+a2
I2L) = (from c - a2ICc ) + (a2-1
>Work IL...0 From property 3 described above, the sum of the zero-sequence circulating current and the load positive-sequence component can be obtained by multiplying the equation 021 by the constant La. Letting this calculated value be B, B=La(EngM −a2
■cd) = La ((from c-a2■cc)+(a2-1
) engineering +1. )=La(Ibc-a2ICc)+(
a2-1) La ko IL = ko oc + (a2-1)
La1lL==---, (14. This calculated value B
is called the calculated value of the zero-sequence circulating current by the negative phase component removal method.

The calculated value B is obtained in the same way when the b-phase and C-phase ground fault occurs.
The calculated value Ea.

Bb and Bc are as shown in Table 6.

Table 6: =-(ku2-1) L role T1 -(boring-1) Toyu I2
L ・・・・・・・・・ α4゛. Therefore (
B-A) is divided by (a2-1) LaIu. Each phase circulation' current oc, ac, I'b
c, What about ICe? ! Since they are in phase, the constants Ka and La have a nearly conjugate relationship. Therefore, the absolute value of the second term on the right side of the equation is as follows. In addition, the content rate of the reverse phase component of the load current ll2L/
IILI can detect the positive phase component of the load current from the equation of at most 5~1 (q because it is 1%!). here,(
Taking the change △C before and after the occurrence of the ground fault for 11f4 of the lrI1 formula, we get: Medium △I+L ・・・・・・・・・
・(17+) It is possible to detect the change in the positive phase portion of the load current △work IL carried by the difference current when the other end is cut off in advance.Considering the same way when the B phase and C phase are grounded, These calculated values are not shown in Table 7 and are constant.

(Margin below) The above is a typical configuration of a three-terminal system with one power supply terminal.

We explained the principle of an example with two load terminals, but in the case of a three-terminal system with two power supply terminals and one square load terminal, when the first trip (earliest cutoff) is detected only in the power supply terminal connection, the second If the trip is too sweet, the timer is overloaded with #, and in the case of a two-terminal system, there is no need to time the timer for both the FiηL source end, the terminal end, and the device.

Below, as an example of the present invention, a case where a common multi-line ground fault line selection joint '@I device is installed at the power transmission end will be described with reference to FIG. 6. This figure shows the three-phase representation of the three-female lineage shown in Figure 2, and the same parts as in Figures 1 and 2 are indicated by the same symbols. point resistor,
31a to 31c and 41a to 4]Of'''j current transformers are shown and connected in a differential circuit with the same phase to form the intercurrent detection section 1.
1 to detect the difference current. - interline controller, current detector 11 iia, , i, tb, iic and ilr
/l is a.

b, c phase, zero phase difference section, and flow detection section are shown. 15 is the first
The a, b, c phase and zero phase difference of the analog current detected by the current detector 11 are shown as Ia, d.
, ■-bd, , Icd, , Iod (ko'fL
(referred to as signal S1) is sampled and analog-to-digital (A/D) converted at a constant period to obtain digital signal S1.
4 (Ia(1°Ibd, :rcd) and S5
Output (Iod)r. 1ZiJ4! Pressure (・C mountain part and connected to the mother Itii7a 1t4 pressure detection section 1゛5 (phase voltage detection transformer) and the second 1↓・, pressure detection section 1.4 (zero phase (voltage detection transformer).,1
6 indicates a data converter of In2, and the analog force a, b, c phase sum detected by the voltage detection unit 12: pressure F2a
.

Eb, IDC (S2) and zero-sequence voltage VO (S3) are A/D-ready and digital %' S6 (Ea, , E
l), Ec) and 57 (VO).

17 is a first filter section, and the first data converter 1
5(7) Input the digital quantities of output S<(Iad, ■bd, ICd), exclude the positive phase components from the line difference currents of the two phases, and output those quantities S8. The digital quantity S8 is the following three l's.

18il-1 is the first compensation constant setting section, and is the above-mentioned (1
) It is possible to set the compensation constants Ka, Kb, and Kc shown in the formula, and output these values 5sffi. Reference numeral 19 denotes a first calculating section, which calculates a calculated value SIO of the zero-sequence circulating current using the positive-sequence component exclusion method from the output S8 of the filter section 17 and the output S9 of the setting section 18. This SIO is the following three calculated values.

2() is a second filter section which inputs the output S4 of the first data conversion section 15 and outputs an amount Sl+ obtained by excluding the negative phase component from the line difference current of the two phases.

This S11 is the following three quantities.

21 is a second compensation constant setting unit, which can set compensation constants La, Lb, and Lc shown in equation 01), and outputs their values SI2. Reference numeral 22 denotes a second function 14, in which a calculated value S1s of the zero-phase circulating current is obtained from the output S11 of the filter section 20 and the output SI2 of the setting section 21 by the reverse phase boundary method. These are the following three calculated values of 5tsid.

Reference numeral 23 denotes a ground fault phase detection unit, which determines the ground fault phase when a one-wire ground fault occurs. As an example, the following calculation is performed by inputting the digital quantities of the a, b, and c phase voltages, which are the output S6 of the second data converter 16.

In addition, IEI2 is the square of the absolute value, m is a scalar coefficient. Outputs the ground fault phase discrimination signal SI4 at the time of a fault.The characteristics are shown in the seventh
As shown in the figure.

j@8 Table 271 is a ground fault detection section. One example is the input of the output S7 of the second data converter 1 (i, that is, the digital quantity of the zero-phase voltage, whose magnitude is a constant value. By performing the above Kfx, a ground fault is detected, and a ground fault detection signal S1
25 is a first selection section, which outputs ground fault phase detection section 2.5. The calculation value Sho of the zero-phase ()u ring current is calculated by the positive-sequence exclusion method at the time of a ground fault in one line of the system, using the ground fault phase discrimination signal SI4. ,. is selected as shown in Table 9 below to obtain output S16.

Table 9 shows the calculation section of PJ3, which includes *, 1 line ground fault, circuit selection ground fault connection 7tj' in the call when the other end is cut off in advance when the line is ground faulted,
The input small current ΔIin of 6 is calculated. This performance-q part 2 (
) is the output S! of the selection unit 25. 6, the calculated value of the zero-sequence circulating current by the positive-sequence exclusion method at the time of the system one-wire ground fault, and the digital needle and ground fault of the zero-sequence differential tunnel flow machine ○d, which becomes the output S5 of the first data converter 15. The ground fault detection signal, which is the output 316 of the fault detection unit 24, is input, and the above-mentioned equation (11) is performed, and the calculation 1 shift Δwork in (SI7) is output.

That is, the calculated value A of the zero-sequence circulating current by the positive-sequence exclusion method is subtracted from the zero-sequence difference current Iod, and the occurrence of a ground fault is detected from the signal SI5, and the change before and after the occurrence of the ground fault is calculated. Expressing this as a formula, it becomes the following C+ formula.

△Work in = (Iod-A) - (Work od-A) Ki I
F・・・・・・・・・
However, od -A indicates the button when the system is preyed upon, and OC1, -A "I" indicates the digit when the system 1 line is grounded.

27 is a second selection unit, which inputs the ground fault phase discrimination signal SI4 and the calculated value St3 of the calculation unit 22, and outputs the ground fault phase discrimination signal S
I4 selects the calculated value S18 of the zero-phase circulating current in the system 1 (tllj) using the negative phase boundary method at the time of a circuit as shown in Table 1, and outputs 818.

Table 10 shows the fourth calculation unit, which detects the change ΔC in the positive phase portion of the load current before and after the occurrence of the ground fault, and outputs the value S19. The calculation unit 28 receives the output S16 of the selection unit 25, which is the calculated value A of the zero-sequence circulating current by the positive-sequence exclusion method at the time of a system 1 line ground fault, and the output 31g of the system 1 line ground fault, which is the output 31g of the selection unit 27. Calculated value B of zero-phase fall 1st pier' 1st flow by reverse phase division method at the time of fault and output SI of ground fault detection section 24.

Input the ground fault fault detection signal that becomes the output, the compensation constants La, Lb, and Lc that are output from the output S12 of the setting section 2, and the ground fault phase discrimination signal that becomes the output S14 of the ground fault phase detection section 2. , the change ΔC after the occurrence of mI in the positive phase component of the load current which appears in the line difference current according to the ground fault phase is determined according to the aforementioned Table 7, and this value S19 is output.

Reference numeral 29 denotes a preceding cutoff detection unit at the other end, which inputs the load weight and the upstream phase change amount ΔC before and after the failure, which becomes the output S19 of the calculation unit 2H, and when this absolute value is above a certain value, the other end It outputs a signal S21 when it determines that the leading end is cut off (a), and outputs a signal S20 when it determines that there is no leading cutting off at the other end because the absolute value is less than a certain value.

3() is the 10th ground fault line selection section, and the output SI7 of the calculation section 26 is ΔI:hn (refer to equation (00)). And the other end advance cutoff detection part 2! Input the signal with no prior cutoff at the other end which becomes the output S20 of J, and select the ground fault line in the period when the system 1 is pure ground fault and the other end is not cut off in advance, and send the ground fault line discrimination signal S22 v S2.
Outputs 3. In this selection section 3o, the input from the calculation section 26 of the period during which the other end is cut off in advance when a ground fault occurs is inputted from the input SI7. Hit・
. . v9, and since it is a fault current component, the ground fault line is determined based on the condition that the other end prior cut-off signal S20 is established. As an example, the following a'y, w formula is used to determine whether the ground fault line is fixed by determining whether the effective component of △ is greater than or equal to a certain value ±ε, with 0 being the polarity -: pressure. I'I] Separate.

q, (△work in −Vo) is the vector inner product value, 1
■Example shows absolute value.

The selection unit 30 determines that there is a ground fault in line 3 when formula (c) is established, and determines that there is a ground fault in line 4 when formula (ψυ) is established, and outputs a ground fault line discrimination signal S22 in the case of a ground fault in line 3. In the case of a ground fault, a determination signal S23 is output.

31 is a second ground fault line selection section, which has a digital view of Δworkin (refer to the equation) which becomes the output 817 of the calculation section 26, and zero-sequence voltage ■○ which becomes the output S7 of the data conversion section 16;
ΔC which becomes the output SI9 of the calculation unit 28 (see Table 7),
The other end pre-cut signal which becomes the output S2+ of the detection unit 29 is inputted, and the ground fault line after the system 1 line ground fault and the other end has been pre-cut is selected, and the ground fault line discrimination signal S is input.
24 and S25 are output.

In this selection unit 31, similarly to the selection unit 30, the relay incoming current after a ground fault occurs and the other end is cut off first is set to the value Δf1n in Table 4, and the load current applied to the relay is The directions of the phase components are set to be in opposite phases at the power source end and the load end, and a ground fault circuit is determined on the condition that a signal indicating a prior cutoff at the other end is established. As an example, the first-order equation 127) and (c)
Use the formula to determine whether there is a ground fault line.

Performance: Part 3 J Kekono ψ F formula is established, and it is determined that line 3 is ground fault U
7, outputs the determination signal S24, and when the threat equation is established, it is determined that there is a ground fault in the wire 4 (b), and outputs the determination signal S25.

Among the outputs of these seven selection units 30 and 31, the ground fault line discrimination signal S22 of line 3. S24 is based on ORGATE 3:3 +-+J! The sum is taken as the trip command S27 for the circuit breaker 6a of line 3, and the ground fault line discrimination signal S of line 4 is calculated.
23.degree.Szs is determined by the OR gate 34 and is then set as the trip command S28 for the circuit breaker 6b of the line 4.

However, limited to power end relays in a 3-terminal system with 1 power supply terminal and 2 load terminals, or 7 power supply end relays in a 3-terminal system with 2 power supply terminals and 1 load terminal, these are indicated by broken line blocks. like,
Off-deal timer section 32 and AND gate 35, 3t
Prepare; In this block, off-delay timer section 3
2 inputs the signal of the other end's leading switch which becomes the output S21 of the other end's leading cutter 29, and after a certain period of time from the input of the signal S21 (the operating time of the line selection ground fault relay M1 and the cutting!a operation). (equivalent to the sum of 1111), the on signal S26
Output. The AND gates 35 and 36 are connected to the OR gate 3 on the condition that the output S26 of the off-delay timer section 32 is satisfied.
The outputs of : and 34 are respectively set as a new trip command (S27) of 1# and 3, and a new trip command (S28) of the ININ type line. It is necessary to add conditions using the on-delay timer section because when the load end is cut off first, the change in the fault current F and the positive phase component of the load current △lI+r is determined by the load end relay, which is the other end. This is because the phase relationship of
2nd trip) up to the load end g? b. Due to the need to lock the vessel.

In addition, in the examples, each part indicated by τ from 17 to 36/
The illumination processing circuit is a computer-generated digital
In addition, in the example (i9), we took a three-terminal system as an example, but it can of course be applied to a two-terminal system as well. It can also be used for IQb systems and parallel 4-line systems.

As described above, according to the present invention, ground faults can be eliminated almost unaffected by the reverse 411 component of current and load current that occur in high-resistance grounding systems in shared multi-circuit systems. This has the effect of allowing you to select the line.

[Brief explanation of drawings]

Figure 1 is an electric wire layout diagram of an ultra-high voltage shared system, and Figure 2 (a). (to), (C) is a system state diagram for explaining a 7-lead strip in a parallel 2-line 3-terminal system, Figure 3 (al,
(b). ((3) is a diagram showing the change direction of the positive phase component of the load phase flow at the own end when the leading cutoff is pre-excited, Figure 4 (a) is a current vector diagram at the own end when the opposite load end is cut off first, Figure 4 (b) is the 'CIL flow vector diagram of the own end when the other end's power supply end is cut off first, @
Figure 5 is a time chart and system state diagram for explaining the response of the other end ground fault line selection relay when the load end is cut off first, and Figure 6 is a shared multi-line system site diagram showing an embodiment of the present invention. A block diagram of the fault line selection relay, and FIG. 7 is a ground fault phase discrimination characteristic diagram. LA, IB, IC, 2A, 2B, 2C... Super υ) Pressure feeding line, 3 al 3bt 3C+ 4 al 4 br
40... High resistance grounding system transmission line, 5... Steel tower, 6
a. tj 'F), (5(2, 6d, 6 e, 6
f...Shiya uh ＜=, 7 a, 7 b,
70---Bus bar, 8m e BE ili, 9a
. gb, gc...-load, 10...neutral point grounding resistor,
Month: line difference current detector, 12/fist/voltage detection section,
13... Transformer for fist phase voltage detection, 14... Transformer for zero phase and pressure detection, 15, 16... Fist data converter, 17
, 20... Filter section, 18, 21... Compensation constant setting section, t-st, 22... Calculation section, 23...
- Ground fault phase detection unit, 24... Ground fault detection unit, 25,
27... SW selection section, 26, 28... Calculation section, 29
. . . Opposite end advance cutoff detection unit, 30, 3] . . . Ground fault line selection unit, 32 . . . Off-delay timer unit. Figure 2 (a) (C) 9a Figure 3 (a) (b) (C)

Claims (1)

[Claims] In a shared multi-line power system, phase difference currents a, b, c between lines of a high resistance grounding system ad, Ibd, ICd
and an inter-line difference current detector (11) for detecting a zero-phase difference between lines (OD), and each of the bus bars of the high resistance grounding system. b, c phase voltage F; a, Eb, EEc and a voltage detection unit (12) that detects the zero-sequence voltage ■○, and the above-mentioned difference current I
ad,■'bd. A first filter section (17) that obtains a signal S8 that excludes the positive sequence component from the difference current between two phases of Icd, and a zero-phase circulating current generator OC and the two sets of phase circulating currents that exclude the positive sequence component. A first calculation unit (19
) and the above difference current Iad, d, 2 of ICd
The second step is to obtain So, which excludes the negative phase component from the difference current between the two phases.
filter section (20), and a compensation constant La, which is the ratio of the zero-phase circulating current to the amount obtained by excluding the negative phase component from the two-phase circulating current.
, Lb, Lc and the above-mentioned quantity So by the negative phase boundary method to obtain the calculated values Ba, Bb, Bc of the zero-sequence circulating current, and the voltage detection section (12).
), which obtains a ground fault phase discrimination signal S+t at the time of a one-wire ground fault from the detection output of
A ground fault detection section (24) which obtains a ground fault detection signal S15 from the detection output of the ground fault detection section (24), and a ground fault detection section (24) which obtains a ground fault detection signal S15 from the above-mentioned discrimination signal SI4 and the calculated values Aa, Ab, AC of the first calculation section (19) A first selection unit (25) that obtains an output SI6 with a selected calculated value, and a relay input before and after a ground fault fault to which the ground fault detection signal SI5 is given from this selection output 816 and the -two-phase difference current ■○d. A third calculation unit (26) that calculates the change in △in and the above-mentioned discrimination signal S+4.
and the calculated values 1"la, Bb of the second calculation unit (22)
, Output SI with the calculated value of the ground fault phase selected from Bc
A second selection unit (27) that obtains 8, and when the upper earth fault detection number S14 is given, the above-mentioned number S16°S's
, SI5 and compensation constants La, Lb, Lc color 111. i13 A fourth calculation unit (28) that calculates the change △C of the positive phase portion of the load current before and after the occurrence of a fault, and when the absolute value of this change △C is a certain value or more, it determines that the other end is leading and sends a signal S21. 16 for output and no preceding cutoff at the other end
The other end leading cutoff detection unit (29) outputs the signal S20, and the effective part of the above change Δworkin is within a certain value range with polarity 0 as the polarity. A ground fault line selection unit (3 (1) and the above variation △ work
Since the effective part of n and △C are within a certain value range with the zero-sequence voltage Vo as the polarity, the above-mentioned signal S of the opposite end is in possession
a second ground fault line selection unit (31) that selects a ground fault line after the KI is given; A shared multi-line system site characterized by comprising: a logic circuit section that obtains a ground fault line discrimination signal for each line from the OR output of the second ground fault line selection section (30), (3)) Fault line selection relay.