JP2969905B2 - Fault detection device for distribution line - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting an accident section in a distribution line.

[Conventional technology]

FIG. 4 shows a conventional fault detection device for distribution lines, in which a distribution switch is divided into a plurality of distribution sections and a junction switch inserted between the distribution feeders. consists distribution system opening and closing of the opening and closing or binding point is performed, a is distribution substation, B ₁ is a circuit breaker provided in power distribution feeder, ground fault detector is connected (not shown). B _11, B ₁₂ ··· are distribution leg of the distribution for the feeder B, B _21, B ₂₂ ··· is sectionalizing switches constantly closed state of each distribution leg, B _211, B ₂₂₁ ··· are timed accident investigation unit, C ₂₁ is the point of attachment switchgear is always in an open circuit state of being inserted into the point of attachment to the distribution section of the other power distribution feeder not shown and distribution section B _14, C ₂₁₁ is a timed accident investigation unit .

Now, when an accident occurs in the distribution section B _13, breaker B ₁
Opens, and the substation ground fault detection device operates. Was closed by reclosing relay, not shown breaker after a predetermined time, re-transmission to the distribution leg B _11. When the distribution section B ₁₁ to power recovery operates timed accident investigation unit B ₂₁₁ is charged with section switch B _21, transmitting power to the power distribution section B _12. Thus the section switch B ₂₂ was charged, when power transmission through a distribution leg B _13, when the distribution section B ₁₃ is a permanent fault, the power distribution segment B ₁₁ operates the breaker B ₁ again, B ₁₂ · ... it is a power failure, both ends of the section switches B ₂₂ of the distribution section B ₁₃ an accident has occurred, B ₂₃ of the closing mechanism is automatically locked. The ground fault detector measures the time until the breaker B ₁ is resumed path, were calculated earth絡点from the measured time. After a certain period of time, circuit breaker B ₁
Was turned on again, and the power distribution section was restored.

[Problems to be solved by the invention]

However, a conventional fault detection device for distribution line faults, when a ground fault occurs, separates the power distribution section where the accident has occurred by repeating power outage and power recovery at least two times from a healthy power distribution section. , Causing great losses to power consumers. Further, the distribution line has a residual voltage and a residual current due to the imbalance of the circuit constants of the three-phase circuit, so that the direction of the ground fault at the time of a minute ground fault cannot be accurately detected.

The present invention has been made to solve such a drawback, and detects the direction of a ground fault at the time of a micro ground fault without a power failure with high precision and accuracy, and an accident occurs at a remote control master station. It is an object of the present invention to be able to detect an existing distribution section.

[Means for solving the problem]

A plurality of sensors provided in the distribution line, vector operation means for performing vector operation on the zero-sequence voltage and zero-sequence current detected by the sensors connected to each sensor, and a ground fault direction from the vector-operated zero-sequence voltage and zero-sequence current. A signal processing unit having a ground fault direction detecting means for detecting, a zero-phase voltage and a zero-phase current detected by the sensor, and a zero-phase voltage in a normal state which is detected several cycles before and stored in a memory of the signal processing unit; Vector operation is performed on the zero-sequence current by the vector operation means to obtain a true zero-sequence voltage and a zero-sequence current. The power distribution unit transmits the signal from the processing unit to the remote control master station, and detects the fault section of the distribution line where the ground fault has occurred from the ground fault direction signal transmitted from each signal processing unit at the remote control master station. In the line fault section detection device, the distribution line Monitors the power supply connected to, outputs an interrupt signal to the CPU when the voltage of the power supply drops below a certain value,
A power supply monitoring circuit for saving measurement data to a memory, and a battery connected to the memory by a changeover switch when the voltage of the power supply becomes a certain value or less.

[Action]

Therefore, even if a micro ground fault occurs in the distribution line, the direction of the ground fault can be accurately detected without being affected by the residual voltage and residual current existing in the distribution line, and the ground fault accident can be detected by the remote control master station. It is possible to detect the accident section where the accident has occurred.

〔Example〕

The present invention will be described with reference to the embodiment shown in FIGS. 1, 2 and 3. FIG. The same parts as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

Section switch B _21, B ₂₂ · · · is the movable electrode 2, and the fixed electrode 3 provided on the container 1, distribution line 4a to the respective electrodes, 4b are connected. 5 is a sensor, a voltage sensor 51 for detecting a line voltage, and a current sensor for detecting a line current.
52, a zero-phase voltage sensor 53 for detecting a zero-phase voltage, and a zero-phase current sensor 54 for detecting a zero-phase current are provided. The zero-phase voltage sensor 53 is configured so that a concentric, non-grounded metal conductor 53a is provided on the outer periphery of the electrode, and a voltage induced by electrostatic induction in the metal conductor is applied to the electro-optic crystal to detect the zero-phase voltage. Have been. The zero-phase current sensor 54 is provided with an annular core (not shown) on the outer periphery of the electrode, and the secondary core and the
A secondary winding 54a is provided, a secondary winding is connected to a burden resistor, and a voltage generated in a tertiary winding by a secondary current induced in the secondary winding is applied to the electro-optic crystal to generate a zero-phase current. It is configured to detect. 55 is an optical fiber whose ends 55a, 5
5b is optically connected to each sensor. 6 are photoelectric converters, 7a, 7b... Are signal processing units, and as shown in FIG.
And the CPU 72 connected to the power supply and the photoelectric converter 6 connected to the CPU.
A / D conversion circuit 73 for converting the signal of
It is composed of a memory 74 for storing PU calculation information. CP
U72 includes a vector calculation means 72a for removing the residual voltage and residual current of the distribution line from the detection signal converted by the A / D converter 73.
And a filter 72b for shaping the signal of the vector operation means
An effective value calculating means 72c for determining whether a signal from the filter exceeds a threshold value, a ground fault direction detecting means 72d for detecting a ground fault direction from an output signal of the filter, and a duration of the ground fault. Is provided with a ground fault continuation time detecting means 72e. Reference numeral 75 denotes a power supply monitoring circuit which operates the changeover switch 76 when the voltage of the power supply 71 falls below a certain value, and connects the battery 77 to the memory. Reference numeral 8 denotes a communication line, and reference numeral 9 denotes a remote control master station.

Next, the operation will be described. When the power distribution section is normally energized, the zero-phase current and voltage are detected by the zero-phase voltage sensor 53 and the zero-phase current sensor 54 provided in the switchgear. After that, it is transmitted to the signal processing units 7a, 7b,. Each signal processing unit
The signal from the photoelectric converter 6 is converted into a digital signal by the A / D converter 73 and output to the vector calculation means 72a of the CPU 72. The vector operation means 72a stores the zero-phase voltage V ₀ and the zero-phase current I ₀ of several cycles, for example, two cycles, in the memory 74, respectively, and stores the zero-phase voltage V ₀₁ , the zero-phase current I ₀₁ detected this time and the memory.
The zero-phase voltage V ₀ and the zero-phase current I ₀ stored in 74 are vector-operated, and the result is output to the filter 72b and the effective value calculating means 72c to determine whether or not a ground fault has occurred. If no fault has occurred in the distribution line, the zero-phase voltage and the zero-phase current detected this time are stored in the memory 74 and updated one after another.

Now, when the ground fault occurs in the distribution section B _13, zero-phase voltage sensor provided in each of the section switch B _21, B ₂₂ · · ·
53, and the zero-phase current sensor 54 are connected to the zero-phase voltage V of the distribution line.
₀₁ , the zero-phase current I ₀₁ is detected and the respective signal processing units 7a, 7
Send to b ... Signal processing section 7a, the 7b · · · vector calculation means 72a is zero-phase voltage sensor 53, and zero-phase zero-phase voltage V ₀₁ detected by the current sensor 54, zeros are stored in the zero-phase current I ₀₁ and the memory Vector operation is performed on the phase voltage V ₀ and the zero-phase current I ₀ to obtain true zero-phase voltage and zero-phase current, which are output to the filter 72b. The waveform is shaped by this filter and the effective value calculating means 72
c to determine whether or not a ground fault has occurred. If a ground fault has occurred, the signal is output to ground fault direction detecting means 72d. The ground fault direction detecting means detects that the phase of the zero-phase current is ahead of the zero-phase voltage by 90 °, and detects that it is occurring downstream of the signal processing unit. It is detected that the error has occurred on the upstream side of the processing unit, and is stored in the memory 74. The ground fault duration is detected by the ground fault
Store in 4. Each signal processing unit transmits a signal in the ground fault direction to the remote control master station, and the remote control master station 9 controls the signal processing units 7a, 7b,.
, A section where the ground fault direction is different is detected, and an accident section where a ground fault accident occurs is detected. In the embodiment, the micro ground fault has been described, but in the case of a ground fault with a power failure, the power supply monitoring circuit 75 monitors the power supply 71 connected to the distribution line, and when the voltage of the power supply 71 drops below a certain value. An interrupt signal is output from the power supply monitoring circuit to the CPU 72, and the CPU 72 stores the currently stored measurement data in the memory 7.
Evacuate to 4. After that, the power switch 76 is switched to enter the backup mode. At the same time, a write inhibit signal to the memory is output. Next, when the power is restored, the changeover switch 76 is switched,
Before the power failure, the ground fault direction signal stored in each memory 74 is transmitted to the remote control master station 9. Further, by using the transmission backup power source, the power failure information can be transmitted to the remote control master station immediately after the power failure.

〔The invention's effect〕

The present invention removes the residual voltage and the residual current of the distribution line by vector operation to obtain the true zero-sequence voltage and zero-sequence current. The direction can be detected with high accuracy, and the fault section where the ground fault has occurred at the remote control master station can be detected, minimizing the labor and time required to investigate the cause of the accident and to maintain and inspect the track. be able to. In addition, there is an effect that it can be used for failure prediction.

[Brief description of the drawings]

FIG. 1 is a power distribution system diagram showing an embodiment of the present invention, FIG. 2 is a schematic diagram showing a configuration of a segmented switch with a built-in sensor, FIG. 3 is a circuit diagram of a signal processing unit, and FIG. It is a system diagram. 1: container, 4a, 4b: distribution line, 5: sensor, 53: zero-phase voltage sensor, 54: zero-phase current sensor, 6: photoelectric converter, 7a, 7b ...: signal processing unit, 71: power supply, 72: CPU, 72a: Vector calculation means, 7
2d: ground fault direction detection means, 73: A / D converter, 74: memory, 75:
Power supply monitoring circuit, 76: Changeover switch, 9: Remote control master station

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-136025 (JP, A) JP-A-1-180469 (JP, A) JP-A-2-101925 (JP, A) JP-A-63-1988 262023 (JP, A) Japanese Utility Model 63-164334 (JP, U) Japanese Utility Model Utility Model 1-131238 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02H 3/32-3 / 52 H02H 7/26 H02J 13/00 301

Claims (1)

(57) [Claims] 1. A plurality of sensors provided in a distribution line, a vector operation means connected to each sensor and performing a vector operation on a zero-phase voltage and a zero-phase current detected by the sensors, and a zero-phase voltage and a zero-phase current obtained by the vector operation A signal processing unit having a ground fault direction detecting means for detecting a ground fault direction from the sensor, and a zero-phase voltage and a zero-phase current detected by a sensor detected several cycles before and stored in a memory of the signal processing unit in a normal state. The vector operation of the zero-phase voltage and the zero-phase current is performed by vector operation means to obtain a true zero-phase voltage and a zero-phase current, and the ground fault direction is detected by the ground-fault direction detection means from the true zero-phase voltage and the zero-phase current. Is calculated and transmitted from the signal processing unit to the remote control master station, and the remote control master station detects the fault section of the distribution line where the ground fault has occurred from the ground fault direction signal transmitted from each signal processing unit. To detect accidental sections of distribution lines A power supply monitoring circuit that monitors a power supply connected to the distribution line, outputs an interrupt signal to the CPU when the voltage of the power supply falls below a certain value, and saves measurement data to a memory, and the voltage of the power supply is below a certain value. And a battery connected to the memory by a change-over switch.