JPH02266822A - Detection of disconnection in distribution line - Google Patents

Abstract

PURPOSE:To make it possible to detect the disconnection of a distributing line and a disconnected block by deciding an open-phase detection block closest to a distributing substation as a disconnected block from among the open-phase detection signals to detect the open-phase for each block and to be supplied from each transmission means. CONSTITUTION:An open-phase detector 14 has a sample hold circuit 14a, an MPX 14b, an A/D conversion section 14c, a data memory 14d, a CPU 14e, etc., and detects that a certain block is in the open-phase state depending on a given condition. The MPX 14b scans the signal from the circuit 14a and supplies it to the A/D conversion section 14c, while the A/D conversion section 14c stores it into the data memory 14d after A/D-converted. The CPU 14e loads the data of the memory 14d and detects that a certain block is open-phase in a single phase and in two-phase. A disconnected block detector 10 decides the closest open-phase block to a distributing substation as a disconnected block where the open-phase is caused depending on the open-phase detection signal for each block supplied through a receiver 9 of a distributing substation 1 and on a block number.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for detecting disconnection in a power distribution line. In more detail, the distribution line is divided into multiple sections,
The present invention relates to a novel distribution line disconnection detection method that detects current and/or voltage in each section and detects distribution line disconnections and disconnection sections based on the detected current and/or voltage.

<Prior art> A distribution substation steps down the power supplied from the power transmission system to a predetermined potential (for example, 6.6 KV) and supplies it in the order of bus bar - circuit breaker - distribution line -> branch line - consumer. This distribution substation is equipped with GPT that detects zero-sequence voltage, ZCT1 that detects zero-sequence current, ground fault direction relay that detects ground faults based on the above-mentioned zero-sequence voltage and zero-sequence current, etc. has been done.

By the way, if one phase of the above distribution line is disconnected, the single-phase loads (loads connected to the disconnected phase) from the point of disconnection will have a power outage, the three-phase loads will be in single-phase operation, and the three-phase loads If it is a rotating device, it will burn out. Furthermore, when two phases of a distribution line are disconnected, no current flows from the disconnection point to the subsequent distribution lines, resulting in a power outage. Therefore, the power distribution substation needs to quickly discover disconnections and disconnected sections, shut off the disconnected sections, and supply power to areas other than the disconnected sections.

This disconnection failure detection requires information such as the current and voltage of each phase at the end of the distribution line (load side). The current and voltage information of each phase at the end of the distribution line (load side) can be obtained from other systems in the power distribution system configured in a loop or network configuration. However, distribution lines without interconnection lines cannot be detected. In other words, if a disconnection occurs after the first branch line, power from the distribution substation will be normally supplied to the first customer, and power will be supplied to the GPT and ZCT of the distribution substation. This is because neither zero-sequence voltage nor zero-sequence current appears, and disconnection cannot be detected at the distribution substation.

In addition, the above-mentioned disconnection section is detected by opening the section switches of all sections, and then turning on and opening the section switches in order to detect a section where a change in voltage or current appears.

Then, after configuring a closed circuit for supplying power to areas other than the detected disconnection section, power is sent back from other interconnected systems.

<Problems to be Solved by the Invention> However, in the above-mentioned disconnection section detection method, since the sectional switches are controlled in order, it takes time to complete the detection of the disconnection section, and power is not supplied to areas other than the disconnection section. There is a problem that supplies cannot be provided quickly.

Furthermore, there is a demand for detecting disconnections and disconnection sections even in power distribution systems that do not have interconnection lines, and quickly restarting power supply.

The present invention has been made in view of the above-mentioned problems and demands, and aims to provide a distribution line disconnection detection method that enables quick detection of distribution line disconnections and disconnection sections. .

Means for Solving the Problems and Effects> In order to achieve the above object, the disconnection detection method of the distribution line of the present invention divides the distribution line into multiple sections using a sectional switch, and divides the distribution line into each of the multiple sections. A plurality of sensors that detect current and/or voltage in electric wires, an open phase detection means that detects open phase in the distribution line based on the current and/or voltage detected by the sensors, and A power distribution system in which a transmission means for transmitting a phase detection signal to a distribution substation is arranged, the distribution substation receives an open phase detection signal from the transmission means arranged in each section, and the open phase detection signal is transmitted. This method is equipped with an open-circuit section detection means that determines the open-phase section closest to the service substation as the open-circuit section.

The invention with the above configuration was made by focusing on the fact that when a distribution line is disconnected, the current in the disconnection phase after the disconnection section becomes zero, and the voltages of each phase become unbalanced. That is, in each section divided by the section switch, a sensor detects current and/or voltage, and an open phase detection means detects an open phase based on the current and/or voltage from the sensor. This open phase detection signal is transmitted by the transmission means to the disconnection section detection means of the distribution substation. The disconnection section detection means detects the disconnection section by determining, from among the open phase detection signals supplied from each transmission means, the open phase section closest to the distribution substation to which the open phase detection signal has been transmitted. can be detected.

In addition, the above-mentioned transmission means transmits data to and from the distribution substation as well as transmits and receives data to the transmission means arranged in other sections, and the open phase detection device transmits data to the distribution line from the transmission means arranged in other sections. If the method detects a disconnection in the section based on current and/or voltage information, the disconnection section detection means of the distribution substation can recognize the disconnection section just by receiving the disconnection section. , the configuration can be simplified.

<Example> Hereinafter, the method for detecting disconnection of a power distribution line according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a power distribution system diagram for implementing the disconnection detection method of the present invention, and FIG. 2 is a block diagram of an open phase detection device.

The distribution substation (1) supplies power stepped down to 6.6KV by the △-△ connection transformer (2) to the busbar (3) and the circuit breaker (
4a) (4b) (4c) Power distribution via &! (5a)
(5b) This is equipment that supplies power to (5c), and this distribution substation (1) includes a GPT (6) that detects the zero-sequence voltage of all systems subordinate to it, and each distribution line (5a). (
5b) z CT (7
a) (7b) (7c), zero-sequence voltage from G P T (6) above, and Z CT (7a) (7b) C
7c> based on the zero-sequence current from the distribution line (5a) (5
b) Ground fault direction relay (8a) to detect ground fault (5c)
) (8b) (8c), receiving device (9a) (9b)
(9c), and disconnection section detection device (10a) (LOb
) (10c) etc. are equipped. The configurations of the above systems are the same, (4a) (4b) (4c), (
5a) (5b) (5c), (7a) (7b) (7
c), (7a) (7b) (7c), (8a) (8
b) (8c), (9a) (9b) (9C), (10
a) (10b) (10e) respectively with the representative number (4)
), (5), (7), (8), (9), 00),
Only (5a) is shown for the configuration on the distribution line side.

The distribution line 6) is equipped with multiple sectional switches (111) (11
2)...(lln), branch line (121) (121)
-112n), and sensor (131) (132)
- (13n) is interposed, sensors (131) (132)
- (13n) open phase detection device (141) (142) -
...(14n) is connected, and the open phase detection device (141)
(142) -... (14n) is the transmission device (151) (
152)=(15n) is connected. The above-mentioned section switches (111) (112)... (lln), sensors (
131) (132)/(18n), open phase detection device (1
41) (141)...(14n), transmission device (1
51) (152) to (15n) have the same configuration, and in the following explanation, the section switch (11), sensor (13), open phase detection device (14), and transmission device (15
).

The sectional switches (11) are arranged at intervals such that the load capacity of one system is approximately the same, and are opened in response to a command from the substation when there is no voltage.

The sensor (13) is placed in front of each sectional switch (11) and detects the current ia, ib, ie and voltage of each phase of a, b, and c. a,? b.? Detect c. This sensor (13)
Instruments that use electromagnetic induction such as CT and PT,
Some devices utilize an electro-optical effect element that detects the electric field of the power distribution line (5) or the magnetic field generated by the current flowing through the power distribution line. In this embodiment, either may be used. Data ta, tb, ic of each phase detected by the sensor (13).

Qa,? b.? c is supplied to the open phase detection device (14).

The open phase detection device (14) includes a sample hold circuit (
14a), MPX (14b), A/D converter (14
c), data memory (14d), CPU (14e
), etc., and the data ia, ib supplied from the sensor (13).

fc,? a,? b and Qc as inputs, and detects that the relevant section is in an open phase state based on predetermined conditions (described later). The sample hold circuit (14a) receives data la from the sensor (13).

Ib, lcS? a, 9b, and 9e are sampled at every predetermined angle and supplied to M P X (14b). Above M
PX (14b) is a sample hold circuit (14a
) is scanned and supplied to the A/D converter (14c). The A/D converter (14c) is M P
The signal from (14b) is converted into a digital signal and stored in the data memory (14d). The above CPU (1
4e) takes in the data stored in the data memory (14d) and detects that the section is one-phase open phase and two-phase open phase. This open phase detection signal is supplied to the transmission device (15).

The transmission device (15) attaches the number of the section to the phase-opening detection signal from the phase-opening detection device (14) and transmits it to the transmission line (1
6). This signal is transmitted via the transmission line (16) to a transmission device located in another section and to a receiving device (9) of the distribution substation (1).

The receiving device (9) of the distribution substation (1) receives the open phase detection signal and the section number from the transmission device (15) arranged in each section, and supplies this to the disconnection section detection device 00). do.

The disconnection section detection device 00) detects the disconnection closest to the distribution substation where the phase disconnection is occurring, based on the phase open detection signal and the section number of each section supplied via the receiving device (9). The phase section is determined to be a disconnected section.

The open phase detection device (14) detects the open phase detection conditions by circuit analysis when one wire is disconnected, circuit analysis when two wires are disconnected, and the voltage when rotating equipment is connected to the load side.
This will be explained in detail based on the current characteristics.

FIG. 3 is a circuit diagram showing a state in which the A phase is disconnected, and FIG. 4 is a diagram showing the voltage at that time as a vector. still,
The left side of the drawing is the power supply side, and the right side is the load side.

1) First, analysis is performed based on the zero-sequence voltage value 0 and the zero-sequence current lO.

Zero-sequence voltage before A phase disconnection! 0 and zero-sequence currents are shown by equation 1 below.

Also, the voltage of each phase? a,♀b,? cs and current ia, i
Since b and ic are in equilibrium, both 90 and lO are in a zero state.

Now, if the C phase is disconnected, Va supplied from the power supply side becomes zero, the voltage vb of the b phase and the voltage of the C phase are vector-added, and the potential of the neutral point is (fb +/c) /
It becomes 2. Since this is equal to the C-phase terminal voltage on the load side, the voltage at the C-phase terminal on the load side is expressed as shown in equation 2 below. a
Voltage 9 whose magnitude is 1/2 and whose phase is 180 degrees apart from
a' appears.

Qb+9c 1 Banquet a' -----1gu a...2 Therefore, the potential difference between the C phase on the power supply side and the C phase on the load side is given by the following formula 3.
As shown, it becomes 39a/2.

? a -(-?a/2) -3? a /2 -3
The zero-sequence voltage on the load side at this time is expressed by the following equation 4.

9O-9a'+9b+? c -- (fb +?c) --Ikkyo a...
・4 Also, when the C phase is disconnected, la is zero, the B phase current ib flows from the B phase terminal - the B phase load - the C phase load → the C phase distribution line, and the C phase current 1c flows from the C phase Terminal - C phase load → B
Phase load - Flows to the B phase distribution line.

The zero-sequence current i0 at this time is expressed by the following equation 5.

io -fb +ic -o ・
...5 That is, when the - wire is disconnected, a zero-sequence voltage of 0 appears, and a zero-sequence current of 10 does not appear.

2) Next, analysis is performed based on the positive sequence current i■ and the negative sequence current 12.

Positive sequence current11. Negative sequence current! 2 is shown by equation 6.

According to the above formula 6, in steady state, the magnitude of the positive sequence current 11 is 311al, and the magnitude of the negative sequence current 12 is zero. However, if the C phase is disconnected, ia −0 and il) +
Since 1e-0, equation 6 becomes the following equation, and α(1-α)
-jJgo, so ll.

12 has a magnitude of /””’Jlib+ and a phase of 1.
80 degrees different.

3) Furthermore, zero-sequence current! A circuit analysis will be conducted focusing on the fact that it is possible to eliminate la by taking the difference between (2) and the negative phase current 12.

By taking the difference between the above equations 6 and rearranging them, the following equation 8 is obtained.

ti-tz-α (1-α) (fb-fc)...8 When the distribution line is normal, that is, in a steady state, ib -
Since 1c-v'd11b+, Equation 8 can be expressed as Equation 9 below.

1l-12-α(1-α)f311b 1-311b+
...9 However, if the C phase is disconnected, Equation 8 becomes Equation 10 below because ib + ic = O.

1t-72-α(1-α)211b+-2l+1bl...lO Also, when the b phase is disconnected, from 1b-0, equation 8 becomes equation 11 below.

1t-i2-α (1-α) ltc -f 1fcl ...11 Also, C
Since it is 1c-0 when the phase is disconnected, Equation 7 becomes the following Equation 12
becomes.

1l-i2-α(1-α)Nbl -1(dfbl...12 That is, from the above formulas 1O111 and 12, 1t-i2 is 2fd11bl when the C phase is disconnected, and J when the b phase is disconnected. Ding 1fcl
, if the C phase is disconnected, 7-1! b becomes 1.

FIG. 5 is a circuit diagram showing a case where the B phase and C phase are disconnected. If the two wires of phase B and phase C are disconnected, connect from the power supply side. b
,? Since c is not supplied, vb-o,? c-0, and the zero-sequence current 90 becomes Qa according to equation 1 above. Also, if the two wires are disconnected, a closed circuit will not be formed, so the phase current tar
ib.

1c is zero, and the zero-sequence current 10, positive-sequence current 11, and negative-sequence current 12 are also zero.

That is, when the two wires are disconnected, the zero-sequence voltage MO appears and the zero-sequence current 10 does not appear, as in the case of the negative wire disconnection.

However, according to experimental results, when a rotating device is connected to the load side, a zero-sequence current 10 appears when the distribution line is disconnected. Therefore, a zero-sequence voltage 90 appears, and a zero-sequence current! There is a risk of making a mistake if it is determined whether the distribution line is disconnected based solely on the fact that 0 does not appear.

In addition to the generation of the above-mentioned zero-sequence current, at the time of a - line disconnection failure, the current in the non-disconnection phase increases. Therefore, when a rotating device is connected to the load side, the presence of the zero-sequence current 10 may lead to erroneous determination of whether the fault is a disconnection or a ground fault.

In addition, in the case of a two-wire disconnection, ia, lb, and ic are all approximately zero, and the zero-sequence current 10 is close to zero, but the voltage of each phase? a,? As shown in FIG. 6, b and vc exhibit a characteristic in that they decrease after a wire breakage and then rise slightly compared to normal times.

Incidentally, the appearance of the zero-sequence current 10 and its various characteristics are well known to those skilled in the art.

Based on the above analysis results and the results of tests conducted by the inventors using a simulated circuit, the open phase detection conditions of the open phase detection means are set as follows.

In addition, ■~■ are the conditions when mainly detecting one-phase open phase, [Yes]~■ are the conditions when mainly detecting two-phase open phase, and @~■ are the conditions when detecting -phase open phase. These are conditions for identifying a phase and a two-phase open phase, and ■, [phase] to 0 are conditions when a rotating device is connected to the load side.

(2) If the vector sum of any two phases of the three-phase currents is zero, one phase is considered to be open. That is, la + ib.

A case where either one of fb+fc and fc+la is zero is defined as one-phase open phase (based on equation 5).

(2) When the edges of any two of the three phases ia, ib, and ic are aligned, one phase is considered to be open. That is, when the negative phase is open, the vector sum of any two phases of the three-phase currents is zero. FIG. 7 shows a schematic diagram when phase comparison is performed using the open phase detection device (14) at the time of - wire breakage.

■The negative load is Qa I-1lb +Qc)l/2, or? b I-
l (?c +9a) l/2, Mataha Vc l-
The case where l (Qa +?b) l, /'2 is defined as one-phase open phase (based on formula 2).

(2) A case where the phase of any one of the phase voltages of the negative load changes by 180 degrees is considered to be one phase open phase (based on formula 2).

■The difference between the voltage information transmitted from the transmission device (15) placed on the power supply side and the voltage information transmitted from the transmission device (15) placed on the load side is greater than the phase voltage before the disconnection. If it is large, one phase is missing (based on formula 3)
.

(2) Detecting a phase open phase based on a sudden change in the current of any one phase.

■, Zero-sequence voltage MO before a predetermined cycle and current zero-sequence voltage -
The case where there is a change in magnitude with respect to VO is considered to be an open phase (Equation 4
(based on).

■If the magnitude of one of Shirakawa, ia, ib, and lc changes and the phase of the changed current is reversed, this is considered to be one phase open phase when rotating equipment is connected to the load side. (Based on Equation 5 and experimental results) ■, l before a given cycle
l' is compared with the current value of 11, and if if/il° is 1, the wire is broken. In addition, the positive sequence current II during steady state is 31fa.
1, and when there is a negative phase, t1 decreases to f1tal, and when there is a two-phase phase loss, t1 decreases to 11-0. Based on this, it is also possible to distinguish between a -phase open phase and a two phase open phase (based on equation 6).

[Co., Ltd.], the case where the magnitude of the positive sequence current 11 and the negative sequence current 12 are equal is considered as a disconnection (based on formula 7). In addition, since 11-i2-0 is established when there is a two-phase open phase, this also holds true when there is a two-phase open phase.

If any one of the internal values of ■, ia, lb, and lc is zero and one of the following formulas is satisfied, it is considered to be one phase open phase (Formula 7
(based on).

t2/(fa or 1b or tc) -v'dingtl/
(ta or ib or tc) --' ding (however, fa, rb, and fe without parentheses are non-zero, that is, the current value of the phase other than the disconnection phase) ■, ia, ib, or lc If the maximum value is approximately equal to lr/77, it is assumed to be a -phase deficit (based on equation 7).

(2) If zero-phase voltage difference 0 is detected and if/12-1, one phase is assumed to be open (based on equation 7). Incidentally, in steady state, it is il/12-oo.

[Yes], the case where fl-12 becomes 2l+tb f+1icl, v'+11c is defined as one phase open phase (based on Formula 10S11.12).

(2) For lfa l, ltb I, and lfc l, the values before a predetermined cycle are compared with the current values, and if any one of the ratios changes significantly, it is determined that one phase is missing.

This means that when a heavy load is connected to the end of a distribution line or two distribution lines, if the load stops operating, l
a, lb, and lc are all zero. There is a possibility that a state where this current is zero may be mistakenly determined to be an open phase. Therefore, in the case of - mutually absent phase, ia, ib.

Erroneous detection can be prevented by focusing on the fact that any one of the ICs becomes zero and defining the case where the ratio of any one changes as one phase open phase.

Note that I la 1. before the predetermined cycle. I fb
I.

It is also possible to detect an open phase based on the difference between 11C1 and the current one.

(Left below) is calculated, and if this is greater than 1, it is considered a disconnection. This is based on the fact that the current in the disconnected phase becomes zero.

In addition, the result of the above calculation is 3/2 when the phase is negative,
When there is a two-phase open phase, it becomes ■.

■If there is a zero-phase voltage -> 0 and all of ia, jb, and lc are zero, it is considered a two-phase open phase (based on the analysis results in Figure 5) [Yes], Qa on the load side, The case where both 9b and Qc are equal is defined as two-phase open phase. That is, the voltage Qa of each phase.

A case where the magnitude and phase of 9b and yc are equal is defined as a two-phase open phase (based on the analysis results in FIG. 5). FIG. 8 shows a schematic diagram when phase comparison is performed when two wires are broken using the open phase detection device (14).

■ Voltage of each phase of negative load? a,? b.? A case where c both decrease by approximately 0° and one unit is considered to be a two-phase open phase. This is based on the results of a disconnection test using a simulated circuit, and it is generally known that such a result can be obtained.

[Phase] If there is a zero-phase voltage MO and the current in one or more of the three phases is zero, it is considered an open phase, and in addition, fa on the load side,
Qb, Qc are both equal, or Qa, Qb on the load side,
9e both decrease by approximately 0.1 bar unit, 2
Assume that the phases are mutually exclusive. This is a combination of the above condition [Yes] (2) and the fact that a zero-sequence voltage appears during an open phase.

■When the maximum of any of ta, fb, and fc is approximately equal to 12, it is assumed to be a two-phase open phase (based on the analysis results in Figure 5).
.

■If there is a zero-sequence voltage MO and any one of la, ib, and ic is zero, it is considered a one-phase open phase, and when there is a zero-sequence voltage MO and all of la, ib, and ic are zero. Let be two-phase open phase. Thereby, it is possible to distinguish between a -phase open phase and a two-phase open phase.

■If the following formula holds and any one of ja, lb, and ic is zero, one phase is considered to be an open phase. If the current value of the phase is 12-β and one or more of !a, tb, and fc is zero, it is considered a two-phase open phase.Thereby, -phase open phase and two-phase open phase Since there is a ground capacitance between the distribution line (5) and the ground, if the distribution line 6) is disconnected, the above β will be This is to take into account that a zero-sequence current of several tens to hundreds of A+A flows. In order to distinguish it from a ground fault, we set this β to about several amperes (′,
O).

(2) The case of 11-J (ia or 1b, ic) is assumed to be one phase open phase, and the case of 12-β-0 is assumed to be two phase open phase (based on formula 7 and the above [phase]).

■There is a zero-sequence voltage -VO, and ? a, fb,
? If c does not increase, the wire is broken. This allows it to be distinguished from a ground fault. That is, when a ground fault occurs, the zero-sequence voltage (0) appears in common, but it differs from a disconnection fault in that 9a, ♀b, and C increase.

[Phase], zero-sequence voltage -VO and zero-sequence current! 0 and the two-phase current increases is considered to be one phase open phase when rotating equipment is connected to the load side, and zero-sequence voltage MO and zero-sequence current! 0 and all three phase currents are near zero, this is considered a two-phase open phase when a rotating device is connected to the load side (based on experimental results) ■, there is a negative sequence current of 12, and A case where any one of IB, ib, and ic is zero is defined as a one-phase open phase, and a case where there is a negative phase current 12 and all of ta, fb, and ic are zero is defined as a two-phase open phase. That is, the negative sequence current 12
occurs also in the case of ground faults and short circuit faults, so f
Distinguish from other failures based on the output conditions of a, ib, and tc,
Further - distinguish between a phase-loss phase and a two-phase phase-loss phase. This allows even if rotating equipment is connected to the load side.
Phase loss can be detected.

[Phase], zero-sequence voltage! One-phase open phase and two-phase open phase are distinguished based on 0 and the above-mentioned condition O. Similar to O above, even if one rotating device is connected to the load side, an open phase can be detected.

Note that the present invention is not limited to the above-described embodiments, and for example, the transmission device transmits and receives current and/or voltage information of the distribution line in the other section by transmitting and receiving with the transmission device located in the other section. It is possible to detect a disconnection in the section based on this, and to send the disconnection detection signal to the distribution substation with a section number attached.

<Effects of the Invention> According to the above first invention, the sensor, the open phase detection means, and the transmission means are arranged in each section divided by the section switch,
An open phase is detected for each section and transmitted to the open circuit section detection means of the distribution substation, and the open circuit section detection means detects the open phase detection signal from among the open phase detection signals supplied from each transmission means to the distribution substation. Since the disconnection section is detected by setting the nearest open phase detection section as the disconnection section, the detection of the disconnection section is easier than the conventional method of opening and closing the section switches in order to detect the disconnection section. It is possible to shorten the time required for the process, and it is also possible to detect disconnections and disconnection sections even in distribution lines that are not interconnected.

[Brief explanation of drawings]

Fig. 1 is a power distribution system diagram for implementing the disconnection detection method of the present invention, Fig. 2 is a block diagram of an open phase detection device, Fig. 3 is a circuit diagram showing a state in which the human phase is disconnected, and Fig. 4 is a vector diagram in the disconnected state in Fig. 3, and Fig. 5 is a vector diagram for the B phase and C phase.
Figure 6 is a voltage-time characteristic diagram when two phase wires are disconnected. Figure 6 is a voltage-time characteristic diagram when a rotating device is connected to the load side. Figure 7 is a schematic diagram when phase comparison is performed when one wire is disconnected. . FIG. 8 is a schematic diagram when phase comparison is performed when two wires are broken. (9)...Receiving device, 00)...Disconnection/ground fault identification device, (11)...Sectional switch, (13)...Sensor, (14)...Open phase detection device, (15)...Transmission device, (1B)...Transmission line diagram diagram diagram diagram diagram diagram

Claims (1)

[Claims] 1. A distribution line is divided into a plurality of sections by a sectional switch, and a plurality of sensors detecting the current and/or voltage of the distribution line for each of the sections, and the current and/or voltage detected by the sensor. /
Alternatively, an open phase detection means for detecting an open phase in a distribution line based on voltage and a transmission means for transmitting an open phase detection signal from the open phase detection means to a distribution substation are installed, and Disconnection section detection means is provided, which receives an open phase detection signal from a transmission means arranged in the section, and determines, as a disconnection section, the open phase section closest to the distribution substation to which the open phase detection signal was transmitted. Features a distribution line disconnection detection method. 2. The transmission means according to claim 1 transmits data to a distribution substation and also transmits and receives data to a transmission means arranged in another section, and the transmission means has an open phase detection device arranged in the other section. A method for detecting a disconnection in a distribution line, characterized in that a disconnection in the section is detected based on current and/or voltage information of the distribution line.