JP2012065446A - Power transmission line accident section detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable it to detect a accident occurrence section accurately without causing a blind area and an overlapped area in the case of dividing a power transmission line into a plurality of sections in order to make a charging current of the power transmission line small.SOLUTION: There are provided: a plurality of photoelectric current sensors S1-S5 which are arranged at different positions along a power transmission line 100, and which detect a current which flows in the power transmission line 100; a digital type current differential relay 104 which, based on the current which two adjacent photoelectric current sensors S1-S5 detect, determines whether an accident has arisen or not in a section sandwiched by the two current sensors S1-S5; and output relays 108 which output information on the section where the digital type current differential relay 104 has determined that an accident has arisen. Photoelectric current sensors S2-S4 other than photoelectric current sensors S1 and S5 of both ends are made to serve a double purpose in order to form sections of both sides of photoelectric current sensors S2-S4, and thereby, a plurality of sections sandwiched by adjacent two photoelectric current sensors S1-S5 are formed contiguously.

Description

  The present invention relates to a power transmission line accident section detection apparatus that detects a power transmission line accident section.

Transmission lines that transmit power are divided into overhead transmission lines and underground transmission lines. An overhead power transmission line lays power cables on steel towers, wooden pillars, concrete pillars, etc., and carries power in the air. Transmission line accidents occur due to factors such as lightning, birds and beasts, wind and rain, and equipment deterioration.
The underground power transmission line is a cable that lays a power cable in a cave or the like and transports the power underground. A transmission line accident occurs due to insulation breakdown of the power transmission equipment due to deterioration of the equipment.

Thus, a transmission line accident section detection device has been developed that attaches various sensors to a power transmission facility and detects in which section of the transmission line an accident has occurred.
Conventional transmission line accident section where current sensors are attached to both ends of underground transmission line, and the fault section where a ground fault occurred in underground transmission line is detected by current differential relay using current detection information of each current sensor The detection device is configured to detect an accident section based on a differential current that is a vector sum of currents flowing from each current sensor into the current differential relay. In the transmission line accident section detection device, measures are taken so that the current differential relay does not operate unnecessarily due to the outflow of the charging current of the underground transmission line that occurs at the time of an accident outside the section.

For example, in the invention described in Patent Document 1, the detection sensitivity of the current differential relay is used as a reference current for determining whether or not an accident has occurred, using a current value in which a predetermined margin is added to the charging current of the underground transmission line. By lowering the value, the current differential relay is prevented from operating unnecessarily. Thereby, it is possible to detect the accident section of the underground power transmission line.
However, in the invention described in Patent Document 1, in order to reliably detect a ground fault, it is necessary to select the detection sensitivity based on the neutral point resistor current (usually 60% to 80%). In a long-distance underground transmission line or the like, there is a problem that the charging current is larger than the neutral point resistor current and thus cannot be applied.

On the other hand, in Patent Document 2, a current transformer is installed at each end of each section of the transmission line divided into several parts, and the difference current between the outputs of both current transformers is detected by the detector. Disclosed inventions are disclosed.
In order to solve the above-described problem relating to the invention described in Patent Document 1, if the invention described in Patent Document 2 is used, a transmission line grounded via a neutral point resistor 111 as shown in FIG. 100 is divided into a plurality of sections (section K1 sandwiched between current sensors S1 and S2, section K2 sandwiched between current sensors S3 and S4), and fault detection is performed with current differential relays RY1 and RY2 for each section K1 and K2. Can be considered.

That is, in FIG. 5, the current differential relay RY1 takes the difference between the currents detected by the current sensors S1 and S2, and determines that an accident has occurred in the section K1 when the difference becomes equal to or greater than a predetermined value. The current differential relay RY2 takes the difference between the currents detected by the current sensors S3 and S4, and determines that an accident has occurred in the section K2 when the difference becomes equal to or greater than a predetermined value. Thereby, it can be determined in which section the accident occurred.
However, in the invention described in FIG. 5, since the current sensors S1, S2, S3, and S4 are arranged at both ends of each section K1, K2 for each section K1, K2, each section is not continuous. There is a problem that an area (blind spot area) NK in which an accident cannot be detected during a section is generated.

As a method of eliminating the blind spot region, as shown in FIG. 6, the transmission line 100 is divided into a plurality of sections (section K3 sandwiched between current sensors S1 and S2, section K4 sandwiched between current sensors S3 and S4), A method of forming a boundary region DK by overlapping a part of each of the sections K3 and K4 is conceivable.
With such a configuration, when an accident occurs in the section K3, it can be detected by the differential relay RY1, and when an accident occurs in the section K4, it can be detected by the RY2 section, resulting in a blind spot region as shown in FIG. Can be prevented.

However, when an accident occurs in the boundary region DK, both the differential relays RY1 and RY2 are detected. Therefore, when an accident is detected by both of the differential relays RY1 and RY2, there is a problem that it is necessary to add a circuit (or human judgment means) for determining that the accident has occurred in the boundary region DK. is there.
Even when a circuit is added in this way, there is a problem that it is impossible to determine whether the accident occurrence location is the boundary area DK or the simultaneous accident over two sections, and the accident occurrence section cannot be specified.

Further, in the invention described in Non-Patent Document 1, the differential current generated by the outflow of the charging current of the underground transmission line at the time of an accident outside the section is in reverse phase to the zero-phase voltage, and the differential generated at the time of the accident inside the section Since the current has the same phase as the zero-phase voltage, the operation of the current differential relay is prevented when the phase discrimination element between the zero-phase voltage and the differential current is in reverse phase.
However, in the invention described in Non-Patent Document 1, the zero-phase voltage may not be taken into the device, and the accident section may not be determined.

JP 2000-321316 A JP-A-6-294837

"Standard concept of system protection relay system (digital edition)" March 1992 Electric Works Federation, Engineering Department

  An object of the present invention is to make it possible to accurately detect an accident occurrence section without generating a blind spot area or an overlapping area when the transmission line is divided into a plurality of sections in order to reduce the charging current of the transmission line. .

  According to the present invention, a plurality of current sensors that are arranged at different positions along a power transmission line, detect a current flowing through the power transmission line, and output a detection signal corresponding to the detected current value; Based on the detection signal from the current sensor, a determination unit that determines whether or not an accident has occurred in a section between the two current sensors, and outputs information on a section in which the determination unit has determined that an accident has occurred. Output section, and a current sensor other than the current sensors at both ends is also used to form sections on both sides of the current sensor, thereby continuously forming a plurality of sections sandwiched between two adjacent current sensors A power transmission line accident section detecting device is provided.

  According to the present invention, when the transmission line is divided into a plurality of sections in order to reduce the charging current of the transmission line, the accident occurrence section can be accurately detected without generating a blind spot area or an overlapping area.

It is a block diagram of the power transmission line accident section detection device concerning each embodiment of the present invention. It is explanatory drawing of the power transmission line accident area detection apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing of the power transmission line accident area detection apparatus which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the power transmission line accident area detection apparatus which concerns on the 3rd Embodiment of this invention. It is explanatory drawing of a power transmission line accident area detection apparatus. It is explanatory drawing of a power transmission line accident area detection apparatus.

FIG. 1 is a block diagram of a power transmission line accident section detection device according to an embodiment of the present invention, and is a block diagram common to each embodiment described later.
In FIG. 1, a plurality of photocurrent sensors S <b> 1 to S <b> 5 are arranged along a power transmission line 100 grounded through a neutral point resistor 111. The photocurrent sensors S1 to S5 are sensors that detect a current flowing through the power transmission line 100 using the Faraday effect.

  The photocurrent sensors S1 to S5 detect the current flowing through the power transmission line 100 at the position where the photocurrent sensors S1 to S5 are arranged, and correspond to the detected current values via the optical cables 110-1 to 110-5. The optical signal to be output is output to the detection unit 102 as a detection signal. Although FIG. 1 shows an example in which five photocurrent sensors S1 to S5 are arranged, a plurality of the photocurrent sensors S1 to S5 may be provided and can be appropriately increased or decreased according to the length of the power transmission line 100 or the like.

Each region sandwiched between two adjacent photocurrent sensors (S1 and S2, S2 and S3, S3 and S4, S4 and S5) constitutes a section for identifying the ground fault occurrence point of the transmission line 100. ing.
Among these current sensors, among the plurality of current sensors S1 to S5 arranged along the transmission line 100, current sensors S2 to S4 other than the current sensors S1 and S5 at both ends are connected to the current sensors S2 to S4. By combining the two sections to form the sections on both sides, a plurality of sections sandwiched between two adjacent current sensors S1 to S5 are continuously formed.

In this way, each section is continuous, and the blind spot area and the overlapping area as described above do not exist.
The photocurrent sensors S <b> 1 to S <b> 5, the optical cables 110-1 to 110-5, and the detection unit 102 constitute a transmission line accident section detection device 101.

  The detection unit 102 receives the detection signals from the photocurrent sensors S1 to S5 via the optical cables 110-1 to 110-5, converts the detection signals into analog electric signals (analog detection signals) having a level corresponding to the detection signals, and outputs the analog electric signals. The accident occurrence section is determined based on the analog detection signals corresponding to the two adjacent photoelectric current sensors S1 to S5 among the analog detection signals input from the photoelectric converter 103 and the photoelectric converter 103. The digital current differential relay 104 that drives the contact of the output relay 108 to be closed, the output relay 108 that is driven to the closed state by the digital current differential relay 104, and the power transmission line A power source 109 is provided for supplying driving power to each electrical component constituting the accident section detecting apparatus 101.

  The digital current differential relay 104 amplifies the analog detection signal from the photoelectric converter 103 and outputs the analog detection signal, and converts the analog detection signal from the analog input unit 105 into a digital signal (digital detection signal). Accident occurs based on digital detection signals corresponding to two adjacent photocurrent sensors S1 to S5 in the digital detection signals input from analog / digital (A / D) converter 106 and A / D converter 106 to be output. A central processing unit (CPU) 107 that determines the section and drives the contact of the output relay 108 corresponding to the accident occurrence section to a closed state is provided.

The photoelectric converter 103 and the analog input circuit 105 are provided in numbers corresponding to the photocurrent sensors S1 to S5, and the output relays 108 are provided in numbers corresponding to the sections. The A / D converter 106 converts analog detection signals input in parallel from the analog input units 105 into digital detection signals in a time division manner and outputs the digital detection signals to the CPU 107 in series. The CPU 107 executes a program stored in a storage unit (not shown) to perform an accident occurrence section determination process and the like as described later.
Here, the photocurrent sensors S1 to S5 constitute current detection means, the detection unit 102 constitutes detection means, and the digital current differential relay 104 constitutes determination means. The photoelectric converter 103 constitutes a photoelectric conversion means, the CPU 107 constitutes a section determination means, and the output relay 108 constitutes an output means.

FIG. 2 is an explanatory diagram of the transmission line accident section detection device according to the first embodiment of the present invention, and the same reference numerals are given to the same parts as those in FIG.
2A to 2D are examples when the number of photocurrent sensors to be used is changed (in other words, when the number of sections for dividing the transmission line 100 is changed), and 2 to 5 light beams are used. A connection relationship between the photocurrent sensors S1 to S5 and the current differential relays RY1 to RY4 when the current sensors S1 to S5 are used is shown.
In FIG. 2, a plurality of photocurrent sensors S <b> 1 to S <b> 5 are arranged along a power transmission line 100 grounded via a neutral point resistor 111. A region sandwiched between two adjacent photocurrent sensors S <b> 1 to S <b> 5 constitutes a section for determining the occurrence of an accident in the power transmission line 100.

  For example, in the example of FIG. 2D, a region sandwiched between the photocurrent sensors S1 and S2, a region sandwiched between the photocurrent sensors S2 and S3, a region sandwiched between the photocurrent sensors S3 and S4, and the photocurrent sensor. Each region sandwiched between S4 and S5 constitutes a section. Among the plurality of photocurrent sensors S1 to S5, the current sensors S2 to S4 other than the current sensors S1 and S5 at both ends are combined to form sections on both sides of the current sensors S2 to S4. A plurality of sections sandwiched between two matching current sensors S1 to s5 are continuously formed.

  Detection signals from the adjacent photocurrent sensors S1 and S2 are input to the input portion of the current differential relay RY1, detection signals from the adjacent photocurrent sensors S2 and S3 are input to the input portion of the current differential relay RY2, Detection signals from adjacent photocurrent sensors S3 and S4 are input to the input portion of the current differential relay RY3, and detection signals from adjacent photocurrent sensors S4 and S5 are input to the input portion of the current differential relay RY4. .

  Each photocurrent sensor S1 to S5 detects a positive current when the current flowing through the transmission line 100 flows in the direction of flowing into each section or when flowing in the direction of flowing out of each section. That is, as shown in FIG. 2D, when the current of the transmission line 100 flows in the direction indicated by the arrow corresponding to each of the photocurrent sensors S1 to S5, it is detected as a positive current and corresponds to the detected current value. When the current of the transmission line 100 flows in the direction opposite to the arrow, the detection signal is detected as a negative current, and the detection signal corresponding to the detected current value is output.

  Based on the detection signals from the photocurrent sensors S1 to S5, the current flowing into each section sandwiched between two adjacent photocurrent sensors (S1 and S2, S2 and S3, S3 and S4, S4 and S5) is added. When the magnitude of the differential current obtained by doing so satisfies a predetermined condition, it is determined that an accident has occurred in a section between the adjacent current sensors S1 to S5.

  More specifically, the current differential relays RY1 to RY4 are magnitudes of differential currents obtained by adding the currents flowing through the transmission line 100 based on detection signals from two adjacent current sensors S1 to S5. Is equal to or greater than a predetermined value, the relay contact is closed, so that it is determined that an accident has occurred in a section sandwiched between the adjacent current sensors S1 to S5. When the magnitude of the differential current obtained by adding the currents flowing through the transmission line 100 based on the detection signals from the two adjacent current sensors S1 to S5 is not greater than or equal to the predetermined value, the current differential relays RY1 to RY4 Does not operate and it is determined that no accident has occurred in the section between the adjacent current sensors S1 to S5.

  The detection polarity of the first photocurrent sensor S1 disposed on one end A of the power transmission line 100 (the current flowing from the one end A to the other end B (arrow direction) is detected as a positive current). As a reference, the detection polarities of the even-numbered photocurrent sensors S2 and S4 are reversed and the detection polarities of the odd-numbered photocurrent sensors S3 and S5 are the same polarity as going to the other end B of the power transmission line 100. That is, the detection polarity of the Nth photocurrent sensor is opposite to that of the first photocurrent sensor S1 when N is an even number, and the same polarity as that of the first photocurrent sensor S1 when N is an odd number. They are arranged as follows.

  Thereby, the Nth (N is a positive integer) th current differential relay N receives the detection signal from the Nth photocurrent sensor N and the detection signal from the (N + 1) th photocurrent sensor (N + 1), respectively. Input with the same polarity, and add differential current (current corresponding to the detection signal from the Nth photocurrent sensor and detection signal from the (N + 1) th photocurrent sensor) by adding AC electric quantity (vector quantity addition) The current obtained by adding the current corresponding to) is detected. In this way, the following four equations (1) are obtained.

Id (1) = I (1) + I (2)
Id (2) = I (2) + I (3)
Id (3) = I (3) + I (4) (1)
Id (4) = I (4) + I (5)
Where Id (N) is the differential current (vector quantity) in the Nth section from one end A, I (N) is the detected current (vector quantity) of the Nth photocurrent sensor SN, I (N + 1) Is the detected current (vector quantity) of the (N + 1) th photocurrent sensor S (N + 1).

The magnitude of the differential current obtained by adding the detection signals from the two adjacent current sensors SN and S (N + 1) (in other words, the detection signal from the two adjacent current sensors SN and S (N + 1)) When the magnitude of the differential current obtained by adding the currents corresponding to (2) is equal to or greater than a predetermined value, it is determined that an accident has occurred in the section N sandwiched between the adjacent current sensors.
In FIG. 2, the current differential relays RY1 to RY4 constitute determination means. In the example of FIG. 2, it is not necessary to reverse the polarity when adding the detection signals output from the photocurrent sensors S1 to S5. However, it is necessary to pay attention to the polarity when installing the photocurrent sensors S1 to S5.

In the first embodiment of the present invention, the detection operation shown in FIG. 2 is performed by the configuration shown in FIG.
Hereinafter, the operation of the transmission line accident section detection device according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
The photocurrent sensors S1 to S5 detect a current flowing through the power transmission line 100 and output a detection signal of an optical signal corresponding to the current flowing through the power transmission line 100 to the detection unit 102 via the optical cables 110-1 to 110-5. To do.

  The photoelectric converter 103 of the detection unit 102 receives the detection signals from the photocurrent sensors S <b> 1 to S <b> 5, converts them into analog electrical signals of corresponding levels, and inputs them to the digital current differential relay 104. The analog input unit 105 amplifies the analog detection signal from the photoelectric converter 103, and the A / D converter 106 converts the analog detection signal into a digital detection signal.

The CPU 107 receives the detection signal in the digital format, and adds the detection signals of the two adjacent photocurrent sensors S1 to S5, respectively, as described with reference to FIG. 2, and the magnitude of the differential current obtained by adding the detection signals. (In other words, the magnitude of the differential current obtained by adding the currents corresponding to the detection signals from the two adjacent current sensors SN and S (N + 1) is predetermined. Determine if it is greater than or equal to the value).
When the CPU 107 determines that the magnitude of the differential current is equal to or greater than a predetermined value, the CPU 107 determines that an accident has occurred in the section, and drives the output relay 108 representing the section to a closed state.
Thus, processing such as displaying a section corresponding to the output relay 108 driven in the closed state on a display device (not shown) is performed.

  As described above, according to the first embodiment of the present invention, a plurality of current sensors S <b> 1 to S <b> 5 that are arranged at different positions along the transmission line 100 and detect the current flowing through the transmission line 100, Based on the current detected by two adjacent current sensors S1 to S5, determination means for determining whether or not an accident has occurred in a section sandwiched between the two current sensors S1 to S5; An output relay 108 that outputs information of the determined section, and by using the current sensors S2 to S4 other than the current sensors S1 and S5 at both ends to form sections on both sides of the current sensors S2 to S4 There is provided a transmission line accident section detecting device characterized in that a plurality of sections sandwiched between two adjacent current sensors S1 to S5 are continuously formed.

  Here, for example, the determination unit adds a current flowing in a section between the two adjacent current sensors S1 to S5 based on detection signals from the two adjacent current sensors S1 to S5. When it is determined that the magnitude of the differential current obtained thereby satisfies a predetermined condition, it is determined that an accident has occurred in a section between the adjacent current sensors S1 to S5.

Further, for example, a plurality of current sensors S1 to S5 are arranged in order from one end side A of the power transmission line 100, and from one end side A on the basis of the detection polarity of the first current sensor S1 from one end side A. The detection polarity of the current sensors S2 and S4 arranged at the even number is reverse polarity, and the detection polarity of the current sensors S3 and S5 arranged at the odd number from the one end A is the same polarity. Based on the detection signals from the two adjacent current sensors S1 to S5, the differential current obtained by adding the current flowing in the section between the two adjacent current sensors S1 to S5 is added. When it is determined that the size satisfies a predetermined condition, it is determined that an accident has occurred in a section between the adjacent current sensors S1 to S5.
Therefore, according to the transmission line accident section detection device according to the first embodiment, when the transmission line is divided into a plurality of sections in order to reduce the charging current of the transmission line, a blind spot region or an overlapping region is generated. It is possible to accurately detect the accident occurrence section.
Further, it can be configured by a small number of photocurrent sensors S1 to S5.

FIG. 3 is an explanatory diagram of a power transmission line accident section detecting apparatus according to the second embodiment of the present invention, and the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.
FIGS. 3A to 3D show examples when the number of photocurrent sensors to be used is changed, and photocurrent sensors S1 to S5 when 2 to 5 photocurrent sensors S1 to S5 are used, respectively. And the connection relationship between the current differential relays RY1 to RY4.

  In FIG. 3, a plurality of photocurrent sensors S <b> 1 to S <b> 5 are arranged along a power transmission line 100 grounded via a neutral point resistor 111. A region sandwiched between two adjacent photocurrent sensors S <b> 1 to S <b> 5 constitutes a section for determining an accident occurrence point of the transmission line 100. In the example of FIG. 3, it is necessary to reverse the polarity when adding the detection signals output from the photocurrent sensors S1 to S5, but when the photocurrent sensors S1 to S5 are installed, all can be installed with the same polarity. There is no need to pay much attention to polarity during installation.

For example, in the example of FIG. 3D, a region sandwiched between the photocurrent sensors S1 and S2, a region sandwiched between the photocurrent sensors S2 and S3, a region sandwiched between the photocurrent sensors S3 and S4, and the photocurrent sensor. Each region sandwiched between S4 and S5 constitutes a section.
Of the detection signals from the adjacent photocurrent sensors S1 and S2, the detection signal from the photocurrent sensor S1 is directly input to one input portion of the current differential relay RY1, and the detection signal from the photocurrent sensor S2 is inverted in polarity. After the polarity is inverted by the circuit 301, the signal is input to the other input portion of the current differential relay RY1.

Similarly, of the detection signals from the adjacent photocurrent sensors S2 and S3, the detection signal from the photocurrent sensor S2 is directly input to one input portion of the current differential relay RY2, and the detection signal from the photocurrent sensor S3. Is inverted by the polarity inverting circuit 302 and then input to the other input portion of the current differential relay RY2.
Of the detection signals from the adjacent photocurrent sensors S3 and S4, the detection signal from the photocurrent sensor S3 is directly input to one input portion of the current differential relay RY3, and the detection signal from the photocurrent sensor S4 is The polarity is inverted by the polarity inverting circuit 303 and then input to the other input portion of the current differential relay RY3.

Of the detection signals from the adjacent photocurrent sensors S4 and S5, the detection signal from the photocurrent sensor S4 is directly input to one input portion of the current differential relay RY4, and the detection signal from the photocurrent sensor S5 is The polarity is inverted by the polarity inverting circuit 304 and then input to the other input portion of the current differential relay RY4.
Each of the photocurrent sensors S1 to S5 is configured to have the same polarity for detecting the current, and detects when the current of the transmission line 100 flows from the one end A to the other end B as a positive current. It is configured. That is, each of the photocurrent sensors S1 to S5 detects a positive current when the current of the transmission line 100 flows in the direction of the arrow shown in association with each of the photocurrent sensors S1 to S5, and reverses the direction of the arrow. When the current of the power transmission line 100 flows through, it is detected as a negative current.

  The Nth current differential relay N inputs the detection current from the Nth photocurrent sensor N as it is, and the detection current from the (N + 1) th photocurrent sensor (N + 1) is inverted in polarity by the polarity inversion circuit. As shown in the following four equations (2), the differential current (the current corresponding to the detection signal from the Nth photocurrent sensor) and (N + 1) are obtained by the addition of the AC electric quantity (the addition of the vector quantity). ) A current obtained by adding the current corresponding to the detection signal from the first photocurrent sensor.

Id (1) = I (1) + (− I (2))
Id (2) = I (2) + (− I (3))
Id (3) = I (3) + (− I (4)) (2)
Id (4) = I (4) + (− I (5))

Where Id (N) is the differential current (vector quantity) in the Nth section from one end A, I (N) is the detected current (vector quantity) of the Nth photocurrent sensor SN, I (N + 1) Is the detected current (vector quantity) of the (N + 1) th photocurrent sensor S (N + 1).
When the magnitude of the differential current obtained by adding the detection signals corresponding to the currents detected by the two adjacent current sensors SN and S (N + 1) satisfies a predetermined condition, for example, the two adjacent current sensors SN , The section N sandwiched between the adjacent current sensors SN and S (N + 1) when the magnitude of the differential current obtained by adding the currents corresponding to the detection signals from S (N + 1) is a predetermined value or more. It is determined that an accident occurred.
In FIG. 3, the current differential relays RY1 to RY4 and the polarity determination circuits 301 to 304 constitute determination means.

In the second embodiment of the present invention, the detection operation shown in FIG. 3 is performed by the configuration shown in FIG.
That is, the CPU 107 calculates the differential current in each section using the detection signals from the photocurrent sensors S1 to S5 according to the equation (2). In a section where the magnitude of the differential current is equal to or greater than a predetermined value, it is determined that an accident has occurred, and the output relay 108 corresponding to the section is driven to a closed state. If there is no section in which the magnitude of the differential current is equal to or greater than a predetermined value, the CPU 107 determines that no accident has occurred.

As described above, according to the transmission line failure section detection device according to the second embodiment, a plurality of transmission lines are provided in order to reduce the charging current of the transmission line, as in the first embodiment. In this case, it is possible to accurately detect the accident occurrence section without generating a blind spot area or an overlapping area.
In the second embodiment, all the current sensors S1 to S5 have the same detection polarity, and the determination means flows into each section detected by two adjacent current sensors S1 to S5. When the magnitude of the differential current obtained by adding the current in the direction to satisfy the predetermined condition, it is determined that an accident has occurred in the section between the two adjacent current sensors S1 to S5. Yes.
Therefore, it is necessary to reverse the polarity when adding the detection signals output from the photocurrent sensors S1 to S5. However, since all of the photocurrent sensors S1 to S5 can be installed with the same polarity, Installation is easy because there is no need to pay much attention.

FIG. 4 is an explanatory diagram of a power transmission line accident section detecting apparatus according to the third embodiment of the present invention, and the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.
4A to 4D show examples when the number of photocurrent sensors to be used is changed, and photocurrent sensors S1 to S5 when 2 to 5 photocurrent sensors S1 to S5 are used, respectively. And the connection relationship between the current differential relays RY1 to RY4.

  In FIG. 4, a plurality of photocurrent sensors S <b> 1 to S <b> 5 are arranged along a power transmission line 100 grounded via a neutral point resistor 111. A region sandwiched between two adjacent photocurrent sensors constitutes a section for determining an accident occurrence point of the transmission line 100. In the example of FIG. 4, it is necessary to reverse the polarity when adding the detection signals output from the photocurrent sensors S1 to S5. However, when the photocurrent sensors S1 to S5 are installed, the first photocurrent sensor S1 is used. Since all can be installed with reverse polarity, it is not necessary to pay much attention to the polarity during installation.

For example, in the example of FIG. 4D, a region sandwiched between the photocurrent sensors S1 and S2, a region sandwiched between the photocurrent sensors S2 and S3, a region sandwiched between the photocurrent sensors S3 and S4, and the photocurrent sensor. Each region sandwiched between S4 and S5 constitutes a section.
Both detection signals from the adjacent photocurrent sensors S1 and S2 are directly input to one input portion and the other input portion of the current differential relay RY1, respectively.

Of the detection signals from the adjacent photocurrent sensors S2 and S3, the detection signal from the photocurrent sensor S2 is inverted in polarity by the polarity inversion circuit 401, and then input to one input portion of the current differential relay RY2. The detection signal from the sensor S3 is directly input to the other input portion of the current differential relay RY2.
Similarly, of the detection signals from the adjacent photocurrent sensors S3 and S4, the detection signal from the photocurrent sensor S3 is inverted in polarity by the polarity inversion circuit 402 and then input to one input portion of the current differential relay RY3. The detection signal from the photocurrent sensor S4 is directly input to the other input portion of the current differential relay RY3.

Of the detection signals from the adjacent photocurrent sensors S4 and S5, the detection signal from the photocurrent sensor S4 is input to one input portion of the current differential relay RY4 after the polarity is inverted by the polarity inversion circuit 403. The detection signal from the photocurrent sensor S5 is directly input to the other input portion of the current differential relay RY4.
Thus, the detection signal detected by the Nth photocurrent sensor is directly input to the current differential relay (N-1) in the (N-1) section, and the polarity is applied to the current differential relay N in the Nth section. Invert and input. Thereby, the differential current detection of the current differential relays RY1 to RY4 in each section can be performed by the same principle formula in all sections as shown by the following four equations (3).

Id (1) = I (1) + I (2)
Id (2) = (− I (2)) + I (3)
Id (3) = (− I (3)) + I (4) (3)
Id (4) = (− I (4)) + I (5)

Where Id (N) is the differential current (vector quantity) in the Nth section from one end A, I (N) is the detected current (vector quantity) of the Nth photocurrent sensor SN, I (N + 1) Is the detected current (vector quantity) of the (N + 1) th photocurrent sensor S (N + 1).
When the magnitude of the differential current obtained by adding the currents detected by the two adjacent current sensors SN and S (N + 1) satisfies a predetermined condition (for example, when the magnitude of the differential current is greater than or equal to a predetermined value) It is determined that an accident has occurred in the section N between the adjacent current sensors.
In FIG. 4, the current differential relays RY1 to RY4 and the polarity determination circuits 401 to 403 constitute determination means.

In the third embodiment of the present invention, the detection operation shown in FIG. 4 is performed by the configuration shown in FIG.
In other words, the CPU 107 uses the detection signals from the photocurrent sensors S1 to S5 to calculate the differential current in each section (the current corresponding to the detection signal from the Nth photocurrent sensor ( N + 1) a current obtained by adding the current corresponding to the detection signal from the nth photocurrent sensor. In a section where the magnitude of the differential current is equal to or greater than a predetermined value, it is determined that an accident has occurred, and the output relay 108 corresponding to the section is driven to a closed state. If there is no section in which the magnitude of the differential current is equal to or greater than a predetermined value, the CPU 107 determines that no accident has occurred.

As described above, according to the power transmission line failure section detecting device according to the third embodiment, a plurality of power transmission lines are provided in order to reduce the charging current of the power transmission line, as in the first embodiment. In this case, it is possible to accurately detect the accident occurrence section without generating a blind spot area or an overlapping area.
A plurality of current sensors S1 to S5 are arranged in order from one end side A of the power transmission line 100, and the determination means uses the detection polarity of the first current sensor S1 from one end side A as a reference. The detection polarity of the other current sensors S2 to S5 is reversed, and the magnitude of the differential current obtained by adding the current flowing in the section detected by the two adjacent current sensors S1 to S5 is predetermined. When the value is equal to or greater than the value, it is determined that an accident has occurred in the section.
Therefore, it is necessary to reverse the polarity when adding the signals output from the photocurrent sensors S1 to S5. However, since all of the photocurrent sensors S1 to S5 can be installed with the same polarity, attention to polarity during installation is required. There is an effect that it is not necessary to pay too much.

In each embodiment, the power transmission line 100 may be either an overhead power transmission line or an underground power transmission line.
In the present invention, the current sensor can be applied to a conventional current transformer (CT) in addition to the above-described photocurrent sensor. However, in the case of a wire-wound CT, the installation of the current sensor requires using a separable CT or otherwise installing the whole around the transmission line at the connection point of the transmission line. On the other hand, in the case of a photocurrent sensor, the current sensor is simply wrapped around the transmission line, so it can be installed at any location, or it can be installed and measured on a trial basis, and then removed easily. There is also a great economic effect.

  It can be applied to the detection of accident sections of overhead transmission lines and underground transmission lines.

DESCRIPTION OF SYMBOLS 100 ... Transmission line 110-1-110-5 ... Optical cable 111 ... Neutral point resistance S1-S5 ... Photocurrent sensor 102 ... Detection part 103 ... Photoelectric converter 104 ...・ Digital type differential current relay 105 ・ ・ ・ Analog input unit 106 ・ ・ ・ Analog / digital converter 107 ・ ・ ・ CPU
108... Output relay 109... Power supply 301 to 304, 401 to 403... Polarity inversion circuit RY1 to RY4.

Claims (6)

A plurality of current sensors that are arranged at different positions along the power transmission line to detect a current flowing through the power transmission line and output a detection signal corresponding to the detected current value;
Determining means for determining whether or not an accident has occurred in a section sandwiched between the two current sensors based on the detection signals from the two adjacent current sensors;
Output means for outputting information of the section determined by the determination means that the accident occurred,
A current sensor other than the current sensors at both ends is also used to form a section on both sides of the current sensor, whereby a plurality of sections sandwiched between two adjacent current sensors are formed continuously. A transmission line accident section detecting device.   The determination means is a magnitude of a differential current obtained by adding a current in a direction flowing into a section sandwiched between the two adjacent current sensors based on a detection signal from the two adjacent current sensors. The transmission line accident section detection device according to claim 1, wherein when it is determined that a predetermined condition is satisfied, it is determined that an accident has occurred in a section sandwiched between the adjacent current sensors. The plurality of current sensors are arranged in order from one end side of the power transmission line, and are arranged evenly from the one end side with reference to the detection polarity of the first current sensor from the one end side. The detection polarity of the current sensor is reverse polarity, and the detection polarity of the current sensor arranged oddly from the one end side is the same polarity,
The determination means is a magnitude of a differential current obtained by adding a current in a direction flowing into a section sandwiched between the two adjacent current sensors based on a detection signal from the two adjacent current sensors. The transmission line accident section detection device according to claim 1, wherein when it is determined that a predetermined condition is satisfied, it is determined that an accident has occurred in a section sandwiched between the adjacent current sensors. The detection polarity of all the current sensors is the same polarity,
The determination means is a magnitude of a differential current obtained by adding a current in a direction flowing into a section sandwiched between the two adjacent current sensors based on a detection signal from the two adjacent current sensors. The transmission line accident section detection device according to claim 1, wherein when it is determined that a predetermined condition is satisfied, it is determined that an accident has occurred in a section sandwiched between the adjacent current sensors. The plurality of current sensors are arranged in order from one end side of the power transmission line, and the first current sensor from the one end side has a polarity opposite to the detection polarity of all other current sensors. Consisting of
The determination means is a magnitude of a differential current obtained by adding a current in a direction flowing into a section sandwiched between the two adjacent current sensors based on a detection signal from the two adjacent current sensors. The transmission line accident section detection device according to claim 1, wherein when it is determined that a predetermined condition is satisfied, it is determined that an accident has occurred in a section sandwiched between the adjacent current sensors. Each of the current sensors is a photocurrent sensor that outputs an optical signal corresponding to a detected current value as the detection signal,
The determination means converts the detection signal from each of the photocurrent sensors into an analog electric signal and outputs it, and converts the analog detection signal from the photoelectric conversion means into a digital detection signal. And an analog / digital conversion means for outputting and a section determination means for determining a section where an accident has occurred based on a detection signal in a digital format from the analog / digital conversion means,
The transmission line accident section detection device according to any one of claims 1 to 5, wherein the output means outputs information of a section determined by the section determination means that an accident has occurred.

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