JPH0746751A - Ground fault distance relay - Google Patents

Abstract

(57) [Summary] [Purpose] In a ground fault distance relay with zero-phase current compensation for parallel lines, prevents the ground fault distance relay of a sound phase from malfunctioning when one phase is open. [Structure] In the case of a ground fault of a parallel two-circuit transmission line, in the ground fault distance relay that determines the fault in the protection section by adding compensation by the zero-phase current of its own line and the adjacent line to each phase current of its own line, And means for introducing circuit breaker conditions for adjacent lines,
A means for changing the compensation degree of the zero phase compensation of the adjacent line to a fixed value smaller than a predetermined value when the adjacent line circuit breaker of the advanced phase is open with respect to the phase under consideration, and the adjacent line circuit breaker of the advanced phase is closed. At this time, a means for returning the compensation degree of the zero-phase compensation of the adjacent line to a predetermined value, and fixing the compensation degree of the zero-phase compensation of the own line smaller than the prescribed value when the own phase circuit breaker of the leading phase with respect to the phase under consideration is open. A means for varying the value and a means for returning the compensation degree of the zero-phase compensation of the own line to a predetermined value when the lead line own-line circuit breaker is closed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground fault distance relay with zero-phase current compensation used for detecting a ground fault in a transmission line.

[0002]

2. Description of the Related Art A distance relay is used as a protective device in an electric power system, and an example of a digital distance relay using a microcomputer therein is shown in FIG. In FIG. 6, the input converter 11 centrally stores the auxiliary PCT, and the voltage and current of the power system are taken in via the input converter 11. Further, the filter (FIL) 12 which extracts only the commercial frequency components of the voltage and current performs filtering. Since each filter output is an analog signal, it is input to an analog / digital converter (A / D) 15 via a sample hold circuit (S / H) 13 and a multiplexer (MPX) 14 to be converted into a digital signal. .

The converted digital signals of voltage and current are temporarily stored in a data memory (hereinafter referred to as RAM) 16. CPU17 is the current stored in RAM,
According to the processing procedure in which the voltage data is stored in the read-only memory 18 (ROM), digital calculation processing (hereinafter referred to as software) of the distance relay is performed. In addition, the input / output circuit (I
/ O) 19 to connect to an external device.

A ground fault distance relay for detecting a ground fault in a parallel two-circuit transmission line is affected by the zero-phase impedance of its own line and that of the line. To measure the distance,
As shown in Eq. (1) below, vector compensation is applied to each phase current of the own line by the zero-phase current of the own line and the adjacent line.
The processing procedure of calculating in PU is implemented.

[0005]

[Equation 1] Therefore, K ₀₁ and K ₀₂ are set as fixed constants.

In recent years, due to the expansion of the scale of the electric power system and the growth of electric power demand, there is a tendency of heavy power flow in the power transmission line. or,
Since many ground faults on power lines are often caused by lightning strikes,
In the event of a ground fault, the accident phase is cut off to promptly eliminate the accident, and the system is operated as much as possible by so-called single-phase reclosing, in which the circuit is reclosed after the accident is removed.
This control is performed by the current differential relay device as the main protection for the purpose of protecting the transmission line, and the distance relay device is used as a backup protection to back up the main protection.

[0007]

As described above, under heavy power flow conditions, when one phase becomes open due to single-phase reclosing, zero-phase current is generated in the line. Therefore, when the compensation degree of the zero-phase current compensation is fixed and handled as in the conventional one, there is a concern that the distance relay of the sound phase malfunctions as described later. For example, in the open phase condition during the single-phase reclosing of the C phase on the own line and the adjacent line, the input of the A phase distance relay is as shown in FIG.
It becomes a tendency like. That is, the influences of the zero-phase currents I ₀₁ and I ₀₂ flowing in the own line and the adjacent line become significant, and depending on the settling, it may be determined that the relay is in the operating range. The present invention has been made to solve the above problems, and prevents malfunction of a healthy phase distance relay in an open-phase state due to heavy power flow, and when a ground fault occurs in the system state described above. However, the purpose is to provide a ground fault distance relay that can be protected as much as possible.

[0008]

A ground fault distance relay according to claim 1 of the present invention is a means for introducing a circuit breaker condition of its own line and an adjacent line, and an adjacent line circuit breaker of a lead phase with respect to a phase under consideration. Means for varying the compensation degree of the zero-phase compensation of the adjacent line to a fixed value smaller than a predetermined value when is open, and the compensation degree of the zero-phase compensation of the adjacent line when the advancing-phase adjacent-line circuit breaker is closed A means for returning to the value, a means for varying the compensation degree of the zero-phase compensation of the own line to a fixed value smaller than a predetermined value when the lead phase own line circuit breaker for the phase under consideration, and a lead phase own line And a means for returning the compensation degree of the zero-phase compensation of the own line to a predetermined value when the breaker is closed.

In the ground fault distance relay according to claim 2 of the present invention, the first means for introducing the main protection trip command for the own line and the adjacent line, and the main protection reclosing start command for the own line and the adjacent line are introduced. A second means for changing the compensation degree of zero-phase compensation of the adjacent line to a fixed value smaller than a predetermined value when the main protection trip command of the leading phase with respect to the phase to be examined is output by the first means; A means for returning the compensation degree of the zero phase compensation of the adjacent line to a predetermined value when the secondary line main protection reclosing is started by the second means, and a self-line main protection trip command for the leading phase of the phase under consideration by the first means. A means for varying the compensation degree of the zero-phase compensation of the own line at the time of output to a fixed value smaller than a predetermined value,
The second means comprises means for returning the compensation degree of the zero-phase compensation of the own line to a predetermined value when the main line main protection reclosing is started.

According to a third aspect of the present invention, there is provided a ground fault distance relay, comprising: a first means for holding an output of a power flow of its own line and an adjacent line at a predetermined value or more for a predetermined period, and a predetermined value of the power flow smaller than the predetermined value. When there is an output by the first means of the leading phase of the adjacent line to the phase to be examined and an output by the second means, the compensation degree of the zero phase compensation of the adjacent line is determined. If there is no output of either the first means or the second means of the advancing phase of the adjoining line and the means for varying the value to a fixed value smaller than the value, the compensation degree of the zero phase compensation of the adjoining line is returned to a predetermined value. Means and first phase of own phase leading phase to be examined
Means for changing the compensation degree of the zero-phase compensation of the own line to a fixed value smaller than a predetermined value when there is an output by the means and the first means of the leading phase of the own line. When there is no output from either of the two means, means for returning the compensation degree of the zero phase compensation of the own line to a predetermined value.

According to a fourth aspect of the present invention, a ground fault distance relay has a first means for judging whether or not the zero-phase current and the anti-phase current of its own line are within a predetermined phase range, and an adjacent line. Second means for determining whether the zero-phase current and the anti-phase current are within a predetermined phase range, and when the first means determines that the lead phase is outside the phase range with respect to the phase under consideration. A means for varying the compensation degree of the zero-phase compensation of the own line to a fixed value smaller than a predetermined value, and a compensation degree of the zero-phase compensation of the adjacent line at the time of starting the adjacent line main protection reclosing of the advanced phase by the second means. Means for returning the value to a value, and means for varying the compensation degree of the zero-phase compensation of the own line to a fixed value smaller than a predetermined value when the own line main protection trip command of the leading phase with respect to the phase under consideration is output by the first means. By the second means, the own line main protection of the leading phase is reset to zero of the own line when reclosing. The compensation of the compensation was composed of a means for returning to a predetermined value.

[0012]

The basic idea of the present invention is that a ground fault distance relay with zero-phase compensation applied to a parallel two-line transmission line is erroneous due to the influence of zero-phase current generated during heavy phase current and open phase. In order to prevent the determination, an attempt is made to change the compensation degree of zero-phase compensation by detecting the time of phase loss. In that sense, claims 1 to 4 are common.

However, claim 1 detects the open phase state of the lead phase with respect to the phase under consideration, reduces the compensation degree of the zero phase compensation of the ground fault distance relay during the open phase, and sets it to a fixed value in other cases. It is a thing. Further, claim 2 uses the main protection trip command of the own line and the adjacent line and the reclosing circuit start information for the open phase judgment, and the claim 3 detects the power flow value of the advancing phase of the adjacent line and the operation of the 67I element and recloses the circuit. The compensation degree is lowered in the absence of voltage. Further, in claim 4, the open phase is judged from the phase relationship between the zero-phase current and the anti-phase current when there is a power flow.

[0014]

Embodiments Embodiments will be described below with reference to the drawings. FIG. 1 is a software processing flow of an embodiment of a ground fault distance relay according to claim 1 of the present invention. The hardware is the same as that of the conventional example shown in FIG.
The same applies to each of the following embodiments. The basic idea is to reduce the degree of zero-phase compensation in the open phase state.

First, in step 1 of the figure, the breaker conditions of the own line and the adjacent line are introduced as contact information via the I / O 19. In step 2, if the adjacent circuit breaker of the lead phase with respect to the predetermined phase to be examined is open (open phase), the compensation degree of the zero phase compensation by the adjacent line is changed to a fixed value K ′ ₀₂ smaller than the predetermined value K _02. Let If the circuit breaker of the adjacent line is closed (not in the open phase), the compensation degree of the zero phase compensation of the adjacent line is returned to the predetermined value K ₀₂ .

Further, step 3 relates to the own line, and if the lead phase own line circuit breaker with respect to the predetermined phase to be examined is open, the compensation degree K ₀₁ for zero-phase compensation of the own line is smaller than a predetermined value. varying the fixed value K _'01. Also, if the lead phase own line circuit breaker is closed, the compensation degree of zero phase compensation of the own line is returned to the predetermined value K ₀₁ . In step 4, the current value for calculation of the ground fault distance relay is obtained according to the compensation degree determined in the above steps. Here, K ₀₁ and K ₀₂ are constants described in the equation (1), and K ′ ₀₁ and K ′ ₀₂ are, for example, 0. As described above, the input to the conventional ground fault distance relay shown in FIG. 7 is improved as shown in FIG. 8 by reducing the zero-phase compensation degree when the circuit breaker is open, that is, in the open phase state. There is no wrong decision.

FIG. 2 is a software processing flow showing an embodiment according to claim 2 of the present invention. In the figure, in step 5, the main protection trip command of the own line and the adjacent line and the reclosing start information are introduced via the I / O. Step 6
In varying the degree of compensation of the zero-phase compensated next line to a small fixed value K _'02 than the predetermined value K ₀₂ next line main protection trip command when the output of the advance phase to consideration phase. At step 7, the compensation degree of the zero-phase compensation of the adjacent line is returned to the predetermined value K ₀₂ when the adjacent line main protection reclosing is started. In step 8, the compensation degree of zero-phase compensation during the period from trip to reclosing is fixed to a fixed value K ′ smaller than a predetermined value.
_This is a flag determination for setting ₀₂ . Step 9 is the same as steps 6, 7 and 8 for the own line. As described above, by reducing the compensation degree of zero-phase compensation during the period from the main protection trip to the reclosing start, that is, the period of the open phase, the same effect as that of claim 1 can be obtained. The means for introducing the I / O 19 described in the embodiments of claims 1 and 2 is not limited to this.
It may be integrated with information transmission or main protection.

FIG. 3 is a flow chart of software processing showing an embodiment according to claim 3 of the present invention. In the figure, in step 10, the power flow of the advancing phase of the adjacent line with respect to the phase under consideration is output at a predetermined value I _K or more (OC "1"), and is returned after a certain period of time at a predetermined value I _K or less (OC "0"). ) Processing. Tide next line in step 11 is output in the following predetermined I _'K (U
C "1") and, thus returning a value I _'K higher (UC
"0"). In step 12 OC "1" and UC "1" the degree of compensation of the zero-phase compensated next line is varied to a small fixed value K _'02 from a predetermined value. OC "1" and UC
"1" returns a degree of compensation of the zero-phase compensated next line if not satisfied a predetermined value K _02. Step 13 is the same processing from step 10 to step 12 described above for the own line. It should be noted that I _K is a rated current because it detects a heavy power flow, for example. Also, I _'K is a value close to 0 in which order to detect the open phase, t is the maximum time required from the trip as a main protective relay device to a reclosing success. As described above, the state of OC "1" and UC "1" is for detecting that the re-closed voltage is not present, and since the compensation degree of the zero-phase compensation is reduced during this period, an effect equivalent to that of claim 1 is obtained. Is obtained.

FIG. 4 is a software processing flow showing an embodiment according to claim 4 of the present invention. In the figure, in step 14, when there is a power flow, the open phase is detected from the phase relationship between the zero-phase current and the reverse-phase current at the open phase (hereinafter, 67I element), and the open phase is detected as the lead phase with respect to the phase under consideration. , The compensation degree of zero-phase compensation is changed to a fixed value smaller than a predetermined value. On the other hand, when the open phase is not detected, the compensation degree of the zero phase compensation is returned to the predetermined value. It should be noted that step 15 will not be described in detail because it can be easily deduced from the above description, but the own line and the adjacent line are processed individually. Here, as an example of the characteristic of the 67I element, FIG. 5 shows a schematic diagram of a vector relationship between the zero-phase current and the anti-phase current when the C-phase is out of phase with a flow. Here, θ is, for example, 60 °. As described above, the 67I element operation means a phase loss, and at this time, the effect equivalent to that of claim 1 is obtained due to the reduction of the compensation degree of the zero phase compensation.

[0020]

As described above, according to the present invention, the phase loss state of the lead phase with respect to the phase under consideration is detected, and when this is the phase loss, the compensation degree of the zero phase compensation of the ground fault distance relay is reduced. With this configuration, it is possible to prevent erroneous determination of the ground fault distance relay due to the zero-phase current that occurs when there is a phase loss due to heavy power flow. A distance relay can be provided.

[Brief description of drawings]

FIG. 1 is a software processing flow showing an embodiment of claim 1 of the present invention.

FIG. 2 is a software processing flow showing an embodiment of claim 2 of the present invention.

FIG. 3 is a flow chart of software processing showing an embodiment of claim 3 of the present invention.

FIG. 4 is a software processing flow showing an embodiment of claim 4 of the present invention.

FIG. 5 shows the relationship between the zero-phase current and the anti-phase current when the C phase is out of phase and 6
The characteristic view of 7I element.

FIG. 6 is a configuration example of a distance relay device.

FIG. 7 is a diagram showing the input to the A-phase ground fault distance relay and the relay operation range when the C-phase is out of phase of the own line and the adjacent line.

FIG. 8 is a diagram showing an input to a phase A ground fault distance relay and a relay operation range when zero phase compensation of the own line and an adjacent line is set to 0.

[Explanation of symbols]

 11 Input converter 12 Filter 13 Sample and hold circuit 14 Multiplexer 15 Analog / digital conversion circuit 16 RAM 17 CPU 18 ROM 19 I / O

Claims (4)

[Claims] 1. A ground fault distance relay for determining a fault in a protection section by adding compensation by a zero-phase current of its own line and an adjacent line to each phase current of its own line in the case of a ground fault of a parallel two-line transmission line, Means to introduce circuit breaker conditions for own line and adjacent line, and when the adjacent line circuit breaker for the advanced phase with respect to the phase under consideration is open, the degree of compensation for zero-phase compensation of the adjacent line can be changed to a fixed value smaller than the specified value. And means for returning the compensation degree of zero-phase compensation of the adjacent line to a predetermined value when the adjacent phase circuit breaker of the leading phase is closed, and when the own phase circuit breaker of the leading phase for the phase under consideration is open. Means for varying the compensation degree of the zero-phase compensation of the own line to a fixed value smaller than a predetermined value, and means for returning the compensation degree of the zero-phase compensation of the own line to the prescribed value when the lead phase own-circuit breaker is closed. A ground-fault distance relay characterized in that it is equipped. 2. A ground fault distance relay for determining an accident in a protection section by adding compensation by a zero-phase current of the own line and an adjacent line to each phase current of the own line in the case of a ground fault of a parallel two-line transmission line, The first means for introducing the main protection trip command for the own line and the adjacent line, the second means for introducing the main protection reclosing start command for the own line and the adjacent line, and the phase to be examined by the first means. On the other hand, means for varying the compensation degree of the zero phase compensation of the adjacent line to a fixed value smaller than a predetermined value when the main protection trip command of the advancing phase is output, and zero of the adjacent line when the adjacent line main protection reclosing is started by the second means. A means for returning the compensation degree of phase compensation to a predetermined value, and the first means for fixing the compensation degree of zero phase compensation of the own line when the main phase protection trip command of the leading phase with respect to the phase under consideration is output. Means for changing the value, and the second means Therefore, the ground fault distance relay, which is provided with means for returning the compensation degree of the zero-phase compensation of the own line to a predetermined value at the time of re-closing the main protection of the own line. 3. A ground fault distance relay for determining a fault in a protection section by adding compensation by the zero-phase currents of the own line and adjacent lines to the ground current of each line in the case of a ground fault of a parallel two-line transmission line, First means for outputting and holding the power flow of its own line and the adjacent line at a predetermined value or more for a certain period of time, second means for outputting the power flow at a predetermined value smaller than the predetermined value or less, and the adjacent line for the phase under consideration. Means for varying the compensation degree of the zero phase compensation of the adjacent line to a fixed value smaller than a predetermined value when there is an output of the leading phase of the first means and an output of the second means, Means for returning the compensation degree of zero-phase compensation of the adjacent line to a predetermined value when there is no output of either the first means or the second means, and the first phase of the leading phase of the own line with respect to the phase under consideration. When there is output by the means and there is output by the second means, A means for varying the compensation degree of the zero-phase compensation to a fixed value smaller than a predetermined value, and a first phase of the leading phase of the own line.
2. A ground fault distance relay, comprising means for returning the compensation degree of zero-phase compensation of its own line to a predetermined value when there is no output from either the means or the second means. 4. A ground fault distance relay for determining an accident in a protection section by adding compensation by the zero-phase currents of the own line and adjacent lines to the ground current of each line in the case of a ground fault of a parallel two-line transmission line, First means for determining whether the zero-phase current and the anti-phase current of the own line are within a predetermined phase range, and whether the zero-phase current and the anti-phase current of the adjacent line are within a predetermined phase range And a first means for determining that the leading phase is out of the phase range with respect to the phase under consideration, the compensation degree of the zero phase compensation of the own line is set to a fixed value smaller than a predetermined value. Means for varying, means for returning the compensation degree of zero-phase compensation of the adjacent line to a predetermined value at the time of starting the adjacent line main protection reclosing of the advanced phase by the second means, and for the phase under consideration by the first means. Main phase protection of leading phase When the trip command is output, the degree of compensation for zero phase compensation of the own circuit is set. And a means for varying the fixed value smaller than a fixed value to a fixed value, and a means for returning the compensation degree of the zero-phase compensation of the own line to a predetermined value at the time of starting the own line main protection reclosing of the leading phase by the second means. Ground fault distance relay.