JP6315829B2 - Disconnection section identification system and disconnection section identification method - Google Patents

Description

  The present invention relates to a disconnected section specifying system and a disconnected section specifying method for specifying a section in which a disconnection of a distribution line has occurred.

  A disconnection detection device for detecting disconnection of a distribution line in a distribution network has been developed. For example, there is a method of detecting disconnection on the upstream side (power supply side) from the voltage detection point by detecting the voltage of each phase of the distribution line (for example, Patent Document 1). Further, there is a method of detecting a line current of each phase of the distribution line and detecting a disconnection on the downstream side (load side) based on the phase difference of each line current (for example, Patent Document 2).

JP 2007-282252 A JP 2009-81905 A

  The inventors of the present application have developed a disconnection detection device capable of detecting both an upstream disconnection and a downstream disconnection (Japanese Patent Application No. 2014-178846). In this case, depending on whether the configuration for detecting the disconnection on the upstream side detects a disconnection or the configuration for detecting the disconnection on the downstream side detects a disconnection, a disconnection has occurred on the upstream side of the disconnection detection device, or on the downstream side. It is possible to determine whether a disconnection has occurred. That is, along with the detection of the disconnection, the direction in which the disconnection has occurred can be determined.

  However, when a distributed power source or a rotating machine is connected to the distribution network in which the disconnection detection device is disposed, the direction in which the disconnection occurs may be erroneously determined. For example, even when a disconnection occurs on the upstream side of the disconnection detection device, the voltage on the downstream side of the disconnection position may be held by the distributed power source or the rotating machine, and the change in voltage may be reduced. In this case, the configuration for detecting the upstream disconnection cannot detect the disconnection. On the other hand, the configuration for detecting the disconnection on the downstream side may detect the disconnection by mistake. In this case, it is erroneously determined that the disconnection has occurred on the downstream side, even though the disconnection has occurred on the upstream side of the disconnection detection device. In this case, since the management device that manages the state of the distribution line based on the information transmitted from each disconnection detecting device receives erroneous information on the disconnection direction, the section where the disconnection occurred is erroneously specified. May end up.

  The present invention has been conceived under the circumstances described above, and an object thereof is to provide a disconnection section specifying system that can appropriately specify a section in which a disconnection has occurred.

  In order to solve the above problems, the present invention takes the following technical means.

  The disconnection section specifying system provided by the first aspect of the present invention includes a plurality of disconnection detection devices that are disposed on a three-phase distribution line and detect that any one of the three-phase distribution lines has been disconnected. A management device that manages the plurality of disconnection detection devices, and the disconnection detection device is based on a reference voltage for each phase based on an electrical signal detected by an electrical signal detector disposed on the distribution line. A current change vector generation unit that generates a current change vector that is a change vector of the line current vector, a disconnection determination unit that determines whether or not a disconnection has occurred in the distribution line, and a disconnection that has occurred by the disconnection determination unit Communication means for transmitting each current change vector generated by the current change vector generation means to the management device when it is determined that the management device includes the disconnection detection device. By comparing more received current change vector, and identifies a section break occurs.

  In a preferred embodiment of the present invention, the management device calculates a matching degree between a current change vector received from a certain disconnection detection device and a current change vector received from another disconnection detection device; And determining means for determining that a disconnection has occurred in a section between the two disconnection detecting devices when the degree of coincidence calculated by the calculating means is less than a predetermined threshold.

  In a preferred embodiment of the present invention, the management device includes the disconnection detection device that transmits the current change vector until the determination unit determines that the degree of coincidence is less than a predetermined threshold. In order from the upstream side, the calculation means calculates the degree of coincidence for the current change vectors received from the disconnection detection device and the disconnection detection device adjacent to the downstream side.

  In preferable embodiment of this invention, the disconnection detection apparatus arrange | positioned most upstream among the said several disconnection detection apparatuses is arrange | positioned at the electric power sending part of a substation.

  In a preferred embodiment of the present invention, the degree of coincidence is calculated based on the phase difference between the phases of the two current change vectors.

  In a preferred embodiment of the present invention, the degree of coincidence is calculated based on a difference in magnitude between the phases of the two current change vectors.

In a preferred embodiment of the present invention, the degree of coincidence ρ has one current change vector as ΔIa (i), ΔIb (i), ΔIc (i), and the other current change vector as ΔIa ( When i + 1), ΔIb (i + 1), and ΔIc (i + 1), they are calculated based on the following formula.

  In a preferred embodiment of the present invention, the threshold value is “0.9”.

  In a preferred embodiment of the present invention, the calculating means transforms one of the current change vectors into a first vector, transforms the other current change vector into a second vector, and the first vector. And the second vector are used to calculate the degree of coincidence.

In a preferred embodiment of the present invention, the degree of coincidence ρ has one current change vector as ΔIa (i), ΔIb (i), ΔIc (i), and the other current change vector as ΔIa ( When i + 1), ΔIb (i + 1), and ΔIc (i + 1), they are calculated based on the following formula.

  In a preferred embodiment of the present invention, the current change vector generation means generates a line current vector for each phase based on the current signal detected by the electrical signal detector, and the voltage detected by the electrical signal detector. A vector generating means for generating a voltage vector for each phase based on the signal, and using the voltage vector for each phase, the line current vector for each phase is converted into a vector based on a reference voltage for each phase; And an arithmetic means for calculating a change vector of the line current vector of each phase after conversion.

In a preferred embodiment of the present invention, the disconnection determining means is configured such that each current change vector generated by the current change vector generating means is
(1) A phase difference of a current change vector of a phase whose phase advances with respect to a current change vector of a certain phase, and a current change vector of the certain phase with respect to a current change vector of a phase whose phase is later than the certain phase Of the first threshold value θ ₁ or more and the second threshold value θ ₂ or less, respectively.
(2) the magnitudes of all current change vectors are greater than or equal to a predetermined threshold I ₀ ;
(3) Not applicable when all of the following (3-1) to (3-2) are satisfied,
(3-1) The phase difference between the current change vector having the maximum size among the current change vectors and the other current change vectors is about 60 °, respectively.
(3-2) The magnitude of the maximum current change vector is about twice the magnitude of the other current change vectors.
If all the conditions are satisfied, it is determined that a disconnection has occurred.

In a preferred embodiment of the present invention, it further comprises a zero-phase voltage detecting means for detecting a zero-phase voltage, and the disconnection judging means is in addition to the conditions (1) to (3),
(4) The zero-phase voltage is not less than a predetermined threshold value V ₀ .
If all the conditions are satisfied, it is determined that a disconnection has occurred.

  The disconnection section specifying method provided by the second aspect of the present invention includes a plurality of disconnection detection devices that are arranged on a three-phase distribution line and detect that any one of the three-phase distribution lines is disconnected. A method of identifying a section in which a disconnection occurs in a system including a management device that manages the plurality of disconnection detection devices, wherein each disconnection detection device is disposed on the distribution line A first step of generating a current change vector that is a change vector of a line current vector with reference to a reference voltage for each phase based on the electrical signal detected by each of the first and second break detection devices; A second step of determining whether or not a disconnection has occurred in the distribution line based on each current change vector generated by the first and second disconnection detection devices, wherein the disconnection has occurred in the second step. If judged The third step of transmitting each current change vector generated in the first step to the management device, and the management device compares the current change vector received from each of the disconnection detection devices, whereby the disconnection is detected. And a fourth step of identifying the generated section.

  According to the present invention, each disconnection detection device transmits a current change vector to the management device when a disconnection is detected. The management device identifies the section where the disconnection occurs by comparing the current change vectors received from the disconnection detection devices. Therefore, the section where the disconnection occurred is more appropriate than the case where the configuration detecting the disconnection on the upstream side of each disconnection detecting device detects the disconnection or the configuration detecting the disconnection on the downstream side detects the disconnection. Can be identified.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a figure showing the whole disconnection section specific system composition concerning a 1st embodiment. It is a figure for demonstrating the disconnection detection apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the case where the connection of a transformer is (DELTA) delta connection. It is a figure for demonstrating the state which a disconnection generate | occur | produced. It is a figure for demonstrating the state which the single phase load fluctuation | variation generate | occur | produced. It is a figure for demonstrating the state which the three-phase load fluctuation | variation generate | occur | produced. It is a figure for demonstrating the case where the connection of a transformer is (DELTA) Y connection. It is a figure which shows the vector at the time of load fluctuation. It is a figure for demonstrating the case where the connection of a transformer is a Ydelta connection. It is a figure which shows the vector at the time of load fluctuation. It is a flowchart for demonstrating a disconnection area specific process. It is a figure for demonstrating the state which the two-phase load fluctuation | variation generate | occur | produced. It is a figure which shows the vector at the time of two-phase load fluctuation | variation. It is a figure for demonstrating the disconnection detection apparatus which concerns on 2nd Embodiment.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a diagram illustrating an overall configuration of a disconnected section identification system according to the first embodiment. The disconnection section specifying system is for specifying an occurrence section when a disconnection occurs, and includes a plurality of disconnection detection devices A1, A2, A3,... A management device C that manages the detection devices A1, A2, A3,. In FIG. 1, four disconnection detection devices A1, A2, A3, and A4 are shown. The disconnection detection device A1 is arranged in the power delivery part of the substation D (that is, the position upstream of the distribution line), and the disconnection detection device A2, the disconnection detection device A3, and the disconnection detection device are sequentially arranged toward the downstream side. A4 is arranged. Each of the disconnection detection devices A1, A2, A3,... Has the same configuration, and is described as a disconnection detection device A when it is described without specifying any one.

  FIG. 2 is a diagram for explaining the disconnection detection apparatus A according to the first embodiment, and shows a state where the disconnection detection apparatus A is arranged on a three-phase distribution line. The three phases consist of an a phase, a b phase, and a c phase. The b phase current is delayed in phase from the a phase current, and the c phase current is advanced in phase from the a phase current.

  The disconnection detection device A detects disconnection of the distribution line. This embodiment demonstrates the case where the disconnection detection apparatus A detects the disconnection of the three-phase distribution line which consists of the a-phase distribution line a, the b-phase distribution line b, and the c-phase distribution line c.

Loads are connected between the distribution lines a, b, and c via the transformer B, respectively. A load Lab is connected between the distribution line a and the distribution line b, a load Lbc is connected between the distribution line b and the distribution line c, and a load Lca is connected between the distribution line c and the distribution line a. Is connected. An instrumental current transformer CT1 is disposed on the distribution line a, an instrumental current transformer CT2 is disposed on the distribution line b, and an instrumental current transformer CT3 is disposed on the distribution line c. . The instrument current transformers CT1, CT2 and CT3 detect currents flowing through the respective distribution lines. Current signals i _a , i _b , and _ic detected by the instrument current transformers CT1, CT2, and CT3, respectively, are input to the disconnection detection device A. Instead of the instrument current transformers CT1, CT2, CT3, other current detection devices (for example, photocurrent measurement) may be used. An instrument transformer PT1 is arranged between the distribution line a and the distribution line b, and an instrument transformer PT2 is arranged between the distribution line b and the distribution line c. An instrument transformer PT3 is disposed between c and the distribution line a. The instrument transformers PT1, PT2, PT3 detect line voltages between the distribution lines, respectively. The voltage signals v _ab , v _bc and v _ca detected by the instrument transformers PT1, PT2 and PT3 are input to the disconnection detection device A. Instead of the instrument transformers PT1, PT2, PT3, other voltage detection devices (for example, capacitor partial pressure) may be used.

  Circuit breakers CB1, CB2, CB3 are provided downstream of the instrument current transformers CT1, CT2, CT3 and the instrument transformers PT1, PT2, PT3. The circuit breakers CB1, CB2, and CB3 block currents flowing through the distribution lines a, b, and c, respectively, in response to the disconnection command input from the disconnection detection device A. The circuit breakers CB1, CB2, and CB3 may be provided upstream of the instrument current transformers CT1, CT2, and CT3 and the instrument transformers PT1, PT2, and PT3.

Breaking detection device A, the current transformer CT1, CT2, the current signal is input from each _{CT3 i a, i b, i} c, and a voltage signal are input from the potential transformer PT1, PT2, PT3 A disconnection is detected based on v _ab , v _{bc, and} v _ca, and a disconnection command for opening the circuit breakers CB1, CB2, and CB3 that are normally closed is output. Further, the disconnection detection device A transmits information indicating that the disconnection has been detected, information on the distribution line in which the disconnection has occurred, and current change vectors ΔIa, ΔIb, ΔIc, which will be described later, to the management device C. The disconnection detection device A includes a current change vector generation unit 1, a downstream disconnection determination unit 2, an effective value calculation unit 3, an upstream disconnection determination unit 4, an interruption command unit 5, and a communication unit 6.

The current change vector generation unit 1 generates a line current vector change vector for each phase voltage reference based on the input voltage signals v _ab , v _bc, v _ca and the current signals i _a , i _{b, ic.} Output. The current change vector generation unit 1 includes a vector generation unit 11, a calculation unit 12, and a storage unit 13.

The vector generation unit 11 generates a line current vector and a line voltage vector for each phase. The a-phase line current vector is Ia, the b-phase line current vector is Ib, the c-phase line current vector is Ic, the a-phase line voltage vector for the b-phase is Vab, and the b-phase line-to-c phase The voltage vector is represented as Vbc, and the line voltage vector of the c phase with respect to the a phase is represented as Vca. The vector generation unit 11 converts the current signals i _a , i _b , and _ic input from the instrument current transformers CT1, CT2, and CT3, respectively, into digital signals, removes harmonic components with a low-pass filter, and amplitudes respectively. And the phase are detected, and line current vectors Ia, Ib, and Ic are generated based on these. The vector generation unit 11 converts the voltage signals v _ab , v _bc , and v _ca input from the instrument transformers PT1, PT2, and PT3, respectively, into digital signals, removes harmonic components with a low-pass filter, The amplitude and phase are detected, and line voltage vectors Vab, Vbc, Vca are generated based on these. The vector generation unit 11 outputs the generated line current vectors Ia, Ib, Ic and the line voltage vectors Vab, Vbc, Vca to the calculation unit 12.

  The calculation unit 12 converts the line current vectors Ia, Ib, and Ic input from the vector generation unit 11 into vectors based on each phase voltage, and generates and outputs a change vector. The calculation unit 12 converts the line current vectors Ia, Ib, and Ic input from the vector generation unit 11 into vectors for each line voltage reference using the line voltage vectors Vab, Vbc, and Vca, and the phase is 30 °. By delaying, it is converted to a vector based on each phase voltage. Then, the line current vectors Ia, Ib, and Ic converted into the respective phase voltage reference vectors are stored in the storage unit 13, and the line current vector before a predetermined time (for example, several tens of milliseconds) is read from the storage unit 13. . The calculation unit 12 inputs the line current vectors Ia, Ib, Ic input from the vector generation unit 11 and converted into vectors based on the respective phase voltages to the line current vectors Ia ′, Ib ′, Current change vectors ΔIa (= Ia′−Ia), ΔIb (= Ib′−Ib), and ΔIc (= Ic′−Ic) are calculated by subtracting from Ic ′ and output to downstream disconnection determination unit 2. .

  Note that when the line current vectors Ia, Ib, and Ic are converted into vectors based on the respective line voltages, for example, the line current vector Ib is converted with reference to the line voltage vector Vab. The phase of the current vector Ic may be delayed by 120 °. In addition, first, change vectors of the line current vectors Ia, Ib, and Ic may be generated, converted into vectors for each phase voltage reference, and output.

  Note that the configuration of the current change vector generation unit 1 is not limited to that described above, and any configuration that generates the current change vectors ΔIa, ΔIb, ΔIc based on each phase voltage may be used. Further, an analog filter may be provided before the vector generation unit 11. The vector generation unit 11 generates line current vectors Ia, Ib, Ic and line voltage vectors Vab, Vbc, Vca every predetermined time, and the calculation unit 12 inputs the line current vectors Ia ′, Ib ′, The current change vectors ΔIa, ΔIb, ΔIc may be calculated from Ic ′ and the line current vectors Ia, Ib, Ic input this time.

  The downstream disconnection determination unit 2 determines the occurrence of disconnection on the downstream side (load side) from the position where the instrument current transformers CT1, CT2, CT3 and the instrument transformers PT1, PT2, PT3 are arranged, and the disconnection occurs. The distribution line is identified, and is realized by, for example, a microcomputer. The downstream disconnection determination unit 2 makes a determination based on the current change vectors ΔIa, ΔIb, ΔIc of each phase voltage reference input from the current change vector generation unit 1. The downstream disconnection determination unit 2 determines that a disconnection has occurred on the downstream side when the current change vectors ΔIa, ΔIb, and ΔIc of each phase voltage reference satisfy a predetermined condition. When the downstream disconnection determination unit 2 determines that a disconnection has occurred on the downstream side, the downstream disconnection determination unit 2 outputs information indicating that the disconnection has occurred and the distribution line in which the disconnection has occurred to the disconnection command unit 5 and the communication unit 6. Further, when the downstream disconnection determination unit 2 determines that the downstream disconnection determination unit 2 itself has a disconnection on the downstream side, and when the upstream disconnection determination unit determines that a disconnection has occurred on the upstream side, The current change vectors ΔIa, ΔIb, ΔIc of the phase voltage reference input from the current change vector generation unit 1 are output to the communication unit 6. The communication unit 6 outputs the current change vectors ΔIa, ΔIb, ΔIc of each phase voltage reference input from the downstream disconnection determination unit 2 to the management device C.

  Below, the conditions for the downstream disconnection judgment part 2 to judge a downstream disconnection are demonstrated.

  If no disconnection occurs on the downstream side and the load connected to the distribution line does not change, the line current vectors Ia, Ib, and Ic do not change. Therefore, the current change vectors ΔIa, ΔIb, and ΔIc (reference values for each phase voltage) Hereinafter, “vectors ΔIa, ΔIb, ΔIc” are all zero vectors. When the disconnection occurs on the downstream side, the line current vectors Ia, Ib, and Ic change, so the vectors ΔIa, ΔIb, and ΔIc also change. However, the vectors ΔIa, ΔIb, ΔIc also change when the load connected between the distribution lines of each phase varies. The downstream disconnection determination unit 2 determines that a disconnection has occurred on the downstream side from the characteristics of the vectors ΔIa, ΔIb, and ΔIc. Specifically, the downstream disconnection determination unit 2 conditionally stores the characteristics of the vectors ΔIa, ΔIb, ΔIc when the disconnection occurs on the downstream side, and the vectors ΔIa, ΔIb, ΔIc match the conditions. By determining whether or not to do so, the occurrence of a disconnection on the downstream side is determined.

  The connection of the transformer B (see FIG. 2) interposed between the distribution line and the load includes a ΔΔ connection, a YY connection, a ΔY connection, a YΔ connection, and the like. In this embodiment, the disconnection can be determined regardless of the connection of the transformer B.

FIG. 3 shows a case where the connection of the transformer B is a ΔΔ connection, and FIG. 3A shows the transformer B and the load connected to the distribution lines a, b and c shown in FIG. Yes. In FIG. 3A, the vector of the current flowing through the load Lab is Iab, the vector of the current flowing through the load Lbc is Ibc, and the vector of the current flowing through the load Lca is Ica. As shown in FIG. 3A, the line current vector Ia of the a-phase distribution line a, the line current vector Ib of the b-phase distribution line b, and the line current vector Ic of the c-phase distribution line c are respectively
Ia = Iab-Ica
Ib = Ibc-Iab
Ic = Ica-Ibc
It becomes. For convenience of calculation, the transformation ratio of the transformer B is “1”. When the transformation ratio is not “1”, the vectors ΔIa, ΔIb, and ΔIc are obtained by dividing the magnitude by the transformation ratio, but the conditions are the same regardless of whether the line is disconnected or the load is changed. , ΔIb, ΔIc are respectively divided by the transformation ratio. Therefore, there is no problem even if the transformation ratio is calculated as “1”.

FIG. 3B shows the current and voltage vectors in the three-phase equilibrium state. The phase voltage vector Va of the a phase, the phase voltage vector Vb of the b phase, and the phase voltage vector Vc of the c phase are 120 degrees apart from each other (indicated by thick arrows in FIG. 3B). . The a-phase line voltage vector Vab for the b-phase, the b-phase line voltage vector Vbc for the c-phase, and the c-phase line voltage vector Vca for the a-phase are respectively
Vab = Va−Vb
Vbc = Vb−Vc
Vca = Vc−Va
(Indicated by broken-line arrows in FIG. 3B). Assuming that the current is advanced in phase θ from the voltage, current vectors Iab, Ibc, and Ica are indicated by thin line arrows in FIG.

となり、ｂ相の相電圧ベクトルＶｂを基準にして、電流ベクトルＩａｂ，Ｉｂｃ，Ｉｃａを表すと、

となり、ｃ相の相電圧ベクトルＶｃを基準にして、電流ベクトルＩａｂ，Ｉｂｃ，Ｉｃａを表すと、

となる。 When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Va of a phase,

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vb of b phase,

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vc of c phase,

It becomes.

FIG. 4A shows a state in which disconnection occurs in the a-phase distribution line a. When disconnection occurs in the distribution line a, no current flows through the distribution line a, so the line current vector Ia becomes a zero vector. The same current flows through the loads Lab and Lca, and this current vector is a vector having the same phase and different magnitude as the current vector Ibc, and can be expressed as αIbc. Therefore,
Ia = 0
Ib = Ibc + αIbc
Ic = −Ibc−αIbc
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the disconnection are
ΔIa = (Iab−Ica) − (0) = Iab−Ica
ΔIb = (Ibc−Iab) − (Ibc + αIbc) = − Iab−αIbc
ΔIc = (Ica−Ibc) − (− Ibc−αIbc) = Ica + αIbc
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。実際の電力系統では、断線時に電圧不足による停電のため、αは「０」に近い値になる。図４（ｂ）は、断線時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。 When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,

It becomes. In an actual power system, α becomes a value close to “0” due to a power failure due to insufficient voltage at the time of disconnection. FIG. 4B shows the vectors ΔIa, ΔIb, ΔIc at the time of disconnection.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of single-phase load fluctuation will be described.

FIG. 5A shows a single-phase load fluctuation and shows a state where the load Lab is disconnected. In this case, as is apparent from FIG.
Ia = -Ica
Ib = Ibc
Ic = Ica-Ibc
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab−Ica) − (− Ica) = Iab
ΔIb = (Ibc−Iab) − (Ibc) = − Iab
ΔIc = (Ica−Ibc) − (Ica−Ibc) = 0
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図５（ｂ）は、単相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。 When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,

It becomes. FIG. 5B shows the vectors ΔIa, ΔIb, ΔIc when the single-phase load fluctuates.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of three-phase load fluctuation will be described.

FIG. 6A shows a three-phase load fluctuation, and shows a state in which the loads Lab, Lbc, and Lca are disconnected. In this case, as is apparent from FIG.
Ia = 0
Ib = 0
Ic = 0
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab−Ica) − (0) = Iab−Ica
ΔIb = (Ibc−Iab) − (0) = Ibc−Iab
ΔIc = (Ica−Ibc) − (0) = Ica−Ibc
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図６（ｂ）は、三相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。 When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,

It becomes. FIG. 6B shows the vectors ΔIa, ΔIb, ΔIc when the three-phase load fluctuates.

  Next, the case where the connection of the transformer B is a ΔY connection will be described.

FIG. 7 shows a case where the connection of the transformer B is a ΔY connection, and FIG. 7A shows the transformer B and the load connected to the distribution lines a, b, and c shown in FIG. Yes. Similarly to FIG. 3A, in FIG. 7A, the current vector flowing through the load Lab is Iab, the current vector flowing through the load Lbc is Ibc, and the current vector flowing through the load Lca is Ica. As shown in FIG. 7A, the line current vector Ia of the a-phase distribution line a, the line current vector Ib of the b-phase distribution line b, and the line current vector Ic of the c-phase distribution line c are respectively
Ia = Iab + Ibc-2Ica
Ib = Ibc + Ica-2Iab
Ic = Ica + Iab-2Ibc
It becomes.

FIG. 7B shows current and voltage vectors in a three-phase equilibrium state. The phase voltage vector Va of the a phase, the phase voltage vector Vb of the b phase, and the phase voltage vector Vc of the c phase are 120 degrees apart from each other (indicated by bold arrows in FIG. 7B). . The a-phase line voltage vector Vab for the b-phase, the b-phase line voltage vector Vbc for the c-phase, and the c-phase line voltage vector Vca for the a-phase are respectively
Vab = Va−Vb
Vbc = Vb−Vc
Vca = Vc−Va
(Indicated by a broken-line thick arrow in FIG. 7B). The voltage vector applied to the load Lab is Vab ′, the voltage vector applied to the load Lbc is Vbc ′, the voltage vector applied to the load Lca is Vca ′, and the phase is 30 with respect to the line voltage vectors Vab, Vbc, Vca, respectively. Go forward. Assuming that the current is advanced in phase θ from the voltage, current vectors Iab, Ibc, Ica are indicated by thin line arrows in FIG.

となり、ｂ相の相電圧ベクトルＶｂを基準にして、電流ベクトルＩａｂ，Ｉｂｃ，Ｉｃａを表すと、

となり、ｃ相の相電圧ベクトルＶｃを基準にして、電流ベクトルＩａｂ，Ｉｂｃ，Ｉｃａを表すと、

となる。 When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Va of a phase,

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vb of b phase,

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vc of c phase,

It becomes.

  When the connection of the transformer B is the ΔY connection, the vectors ΔIa, ΔIb, ΔIc at the time of the disconnection are the same as those in FIG.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of single-phase load fluctuation will be described.

When the load Lab is disconnected and Iab = 0,
Ia = Ibc-2Ica
Ib = Ibc + Ica
Ic = Ica-2Ibc
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab + Ibc-2Ica) − (Ibc-2Ica) = Iab
ΔIb = (Ibc + Ica−2Iab) − (Ibc + Ica) = − 2Iab
ΔIc = (Ica + Iab−2Ibc) − (Ica−2Ibc) = Iab
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図８（ａ）は、単相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。 When the line current vector based on each phase voltage is set as I and the vectors γVa, γVb, and γVc are replaced with the vector I, respectively,

It becomes. FIG. 8A shows the vectors ΔIa, ΔIb, ΔIc when the single-phase load fluctuates.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of three-phase load fluctuation will be described.

When the loads Lab, Lbc, and Lca are disconnected,
Ia = 0
Ib = 0
Ic = 0
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab + Ibc−2Ica) − (0) = − 3Ica
ΔIb = (Ibc + Ica−2Iab) − (0) = − 3Iab
ΔIc = (Ica + Iab−2Ibc) − (0) = − 3Ibc
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図８（ｂ）は、三相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。 When the line current vector based on each phase voltage is set as I and the vectors γVa, γVb, and γVc are replaced with the vector I, respectively,

It becomes. FIG. 8B shows the vectors ΔIa, ΔIb, ΔIc when the three-phase load fluctuates.

  Next, a case where the connection of the transformer B is a YΔ connection will be described.

FIG. 9 shows a case where the connection of the transformer B is a YΔ connection, and FIG. 9A shows the transformer B and the load connected to the distribution lines a, b and c shown in FIG. Yes. Similarly to FIG. 3A, in FIG. 9A, the current vector flowing through the load Lab is Iab, the current vector flowing through the load Lbc is Ibc, and the current vector flowing through the load Lca is Ica. As shown in FIG. 9A, the line current vector Ia of the a-phase distribution line a, the line current vector Ib of the b-phase distribution line b, and the line current vector Ic of the c-phase distribution line c are respectively
Ia = (2/3) Iab- (1/3) Ibc- (1/3) Ica
Ib = (2/3) Ibc- (1/3) Ica- (1/3) Iab
Ic = (2/3) Ica- (1/3) Iab- (1/3) Ibc
It becomes.

  FIG. 9B shows current and voltage vectors in a three-phase equilibrium state. The phase voltage vector Va of the a phase, the phase voltage vector Vb of the b phase, and the phase voltage vector Vc of the c phase are 120 degrees apart from each other (indicated by thick arrows in FIG. 9B). . The a-phase line voltage vector Vab for the b-phase, the b-phase line voltage vector Vbc for the c-phase, and the c-phase line voltage vector Vca for the a-phase are equal to the phase voltage vectors Va, Vb, and Vc, respectively. . Assuming that the current is advanced in phase θ from the voltage, current vectors Iab, Ibc, and Ica are indicated by thin line arrows in FIG.

となり、ｂ相の相電圧ベクトルＶｂを基準にして、電流ベクトルＩａｂ，Ｉｂｃ，Ｉｃａを表すと、

となり、ｃ相の相電圧ベクトルＶｃを基準にして、電流ベクトルＩａｂ，Ｉｂｃ，Ｉｃａを表すと、

となる。 When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Va of a phase,

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vb of b phase,

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vc of c phase,

It becomes.

  When the connection of the transformer B is the YΔ connection, the vectors ΔIa, ΔIb, ΔIc at the time of the disconnection are the same as those in FIG.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of single-phase load fluctuation will be described.

When the load Lab is disconnected and Iab = 0,
Ia =-(1/3) Ibc- (1/3) Ica
Ib = (2/3) Ibc- (1/3) Ica
Ic = (2/3) Ica- (1/3) Ibc
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (2/3) Iab− (1/3) Ibc− (1/3) Ica) − (− (1/3) Ibc− (1/3) Ica) = (2/3) Iab
ΔIb = ((2/3) Ibc− (1/3) Ica− (1/3) Iab) − ((2/3) Ibc − ((1/3)) Ica) = − (1/3) Iab
ΔIc = ((2/3) Ica− (1/3) Iab− (1/3) Ibc) − ((2/3) Ica− (1/3) Ibc) = − (1/3) Iab
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図１０（ａ）は、単相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。 When the line current vector based on each phase voltage is set to I and the vectors εVa, εVb, and εVc are replaced with the vector I, respectively,

It becomes. FIG. 10A shows the vectors ΔIa, ΔIb, ΔIc when the single-phase load fluctuates.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of three-phase load fluctuation will be described.

When the loads Lab, Lbc, and Lca are disconnected,
Ia = 0
Ib = 0
Ic = 0
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = ((2/3) Iab− (1/3) Ibc− (1/3) Ica) − (0) = Iab
ΔIb = ((2/3) Ibc− (1/3) Ica− (1/3) Iab) − (0) = Ibc
ΔIc = ((2/3) Ica− (1/3) Iab− (1/3) Ibc) − (0) = Ica
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図１０（ｂ）は、三相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。 When the line current vector based on each phase voltage is set to I and the vectors εVa, εVb, and εVc are replaced with the vector I, respectively,

It becomes. FIG. 10B shows the vectors ΔIa, ΔIb, ΔIc when the three-phase load fluctuates.

  When the connection of the transformer B is the YY connection, it is the same as the case of the ΔΔ connection. It should be noted that the two-phase load fluctuation occurs only in a very special state and hardly occurs in practice, and therefore, this embodiment does not assume a case where the two-phase load fluctuation occurs.

  As described above, the vectors ΔIa, ΔIb, and ΔIc have a case where a disconnection occurs on the downstream side (see FIG. 4B) and a case where a load change occurs (see FIGS. 5B and 6B). Different vectors are obtained in FIGS. 8A, 8B, 10A, and 10B. When the vectors ΔIa, ΔIb, and ΔIc become the vectors shown in FIG. 4B, it can be determined that a disconnection has occurred on the downstream side. However, when the load fluctuates, there is no problem considering that the load is approximately balanced. However, when the downstream side is disconnected, the load on the load side is not always balanced from the disconnection point, as shown in FIG. Deviations from the vector diagram may occur. It is also necessary to take into account that measurement errors occur in the instrument current transformers CT1, CT2, CT3 or the instrument transformers PT1, PT2, PT3. That is, even if these errors are included, the vectors ΔIa, ΔIb, ΔIc are the vectors shown in FIG. 4B, and FIG. 5B, FIG. 6B, FIG. It is necessary to set conditions that can be determined not to be the vectors shown in (b) and FIGS. 10 (a) and 10 (b).

In the present embodiment, the following conditions are set as conditions for determining the occurrence of downstream disconnection.
(1) Phase difference of a phase voltage reference current change vector of a phase whose phase is advanced from a phase with respect to a current change vector of a phase voltage reference of a phase, and a phase voltage reference current change of a phase lagging a phase The phase difference of the current change vector based on the phase voltage of a certain phase with respect to the vector is not less than the first threshold θ _{1 and not} more than the second threshold θ ₂ , respectively.
(2) The magnitude of the current change vector based on the phase voltage of all phases is equal to or greater than a predetermined threshold value I ₀ .
(3) Not applicable if all of the following conditions are met.
(3-1) The phase difference between the vector having the largest magnitude among the current change vectors based on the phase voltage of each phase and the other vectors is about 60 °.
(3-2) The size of the maximum vector is about twice the size of the other vectors.

In the present embodiment, a value of 5 ° to 30 ° is set as the first threshold θ ₁ , a value of 150 ° to 180 ° is set as the second threshold θ ₂ , and a value of several amperes is set as the predetermined threshold I _0. Is set.

The above condition (1) is that, for example, when the “certain phase” is the a phase, the phase difference between the current change vector based on the phase voltage of the a phase and the current change vector based on the phase voltage of the c phase is θ ₁ to θ _2. And the phase difference of the current change vector of the a-phase phase voltage reference to the current change vector of the b-phase phase voltage reference is in the range of θ ₁ to θ ₂ .

  The condition (3) above is that the vector does not correspond to the vectors shown in FIGS. 8 (a) and 10 (a). When no power failure occurs due to disconnection, that is, when α is (1/2), the vector shown in FIG. 4B and the vectors shown in FIGS. 8A and 10A can be discriminated. difficult. However, it is unlikely that no power outage will occur in the actual system. Therefore, when the vectors ΔIa, ΔIb, ΔIc correspond to the vectors shown in FIG. 8A or FIG. 10A, there is no problem even if it is determined that the load is not a disconnection but a load change. In the present embodiment, the condition (3-1) is determined based on whether each phase difference is within a range of 60 ° ± 5 °. Further, it is determined whether or not the condition (3-2) is within a range of 1.9 to 2 times.

  The conditions (1) to (3) described above are examples of conditions for determining the occurrence of downstream disconnection, and the conditions set in the downstream disconnection determination unit 2 are not limited thereto. The conditions for determining the occurrence of the downstream disconnection are based on the case where the disconnection occurs on the downstream side (see FIG. 4B) based on the vectors ΔIa, ΔIb, ΔIc, and the case where a load change occurs (see FIG. 4). 5 (b), FIG. 6 (b), FIG. 8 (a), (b), FIG. 10 (a), and (b)) may be used.

  The downstream disconnection determination unit 2 generates a disconnection on the downstream side of the distribution line when the vectors ΔIa, ΔIb, ΔIc input from the current change vector generation unit 1 satisfy all the above conditions (1) to (3). Judge.

  In the above description, the vector diagrams of the vectors ΔIa, ΔIb, and ΔIc when the loads are disconnected as the load fluctuation occurs (FIGS. 5B, 6B, 8A, and 8A) ( b) and FIGS. 10A and 10B). When the load decreases, only the lengths of the vectors ΔIa, ΔIb, and ΔIc in each diagram are different. When the load increases, the directions of the vectors ΔIa, ΔIb, and ΔIc in each diagram are simply reversed by 180 °. is there. Therefore, these cases can also be distinguished from those at the time of occurrence of downstream disconnection using the above conditions (1) to (3).

Returning to FIG. 2, the effective value calculation unit 3 calculates effective values Vrmsab, Vrmsbc, and Vrmsca of each line voltage based on the input voltage signals v _ab , v _bc , and v _ca. The effective value calculation unit 3 outputs the calculated effective values Vrmsab, Vrmsbc, and Vrmsca to the upstream disconnection determination unit 4.

  The upstream disconnection determination unit 4 determines the occurrence of disconnection on the upstream side (power supply side) from the position where the instrument current transformers CT1, CT2, CT3 and the instrument transformers PT1, PT2, PT3 are disposed. The distribution line is identified, and is realized by, for example, a microcomputer. The upstream disconnection determination unit 4 makes a determination based on the effective values Vrmsab, Vrmsbc, and Vrmsca of each line voltage input from the effective value calculation unit 3. In normal times, the effective values Vrmsab, Vrmsbc, and Vrmsca are substantially similar values. However, when a disconnection occurs on the upstream side, the line voltage related to the disconnected distribution line decreases. For example, when disconnection occurs in the a-phase distribution line a, the effective values Vrmsab and Vrmsca are lowered. The upstream disconnection determination unit 4 determines that a disconnection has occurred on the upstream side when any two of the effective values Vrmsab, Vrmsbc, and Vrmsca are lower than the remaining one by a predetermined value or more. Further, the upstream-side disconnection determination unit 4 determines the disconnected distribution line according to which two values have decreased. When the upstream side disconnection determination unit 4 determines that a disconnection has occurred on the upstream side, the upstream side disconnection determination unit 4 outputs information indicating that the disconnection has occurred and the distribution line in which the disconnection has occurred to the cutoff command unit 5 and the communication unit 6. The upstream disconnection determination unit 4 also outputs a signal indicating that a disconnection has occurred to the downstream disconnection determination unit 2. When the downstream disconnection determination unit 2 receives a signal indicating that a disconnection has occurred from the upstream disconnection determination unit 4, the downstream side disconnection determination unit 2 receives the vectors ΔIa, ΔIb, ΔIc input from the current change vector generation unit 1 as the communication unit 6. Output to. The communication unit 6 outputs the vectors ΔIa, ΔIb, ΔIc input from the downstream disconnection determination unit 2 to the management device C.

  The interruption command unit 5 outputs an interruption command to the circuit breakers CB1, CB2, and CB3 based on information input from the downstream disconnection determination unit 2 or the upstream disconnection determination unit 4. When the information indicating that the disconnection has occurred is input, the breaker command unit 5 outputs a breaker command to the breakers CB1 to CB3 and opens the breakers CB1 to CB3.

  The communication unit 6 transmits information input from the downstream disconnection determination unit 2 or the upstream disconnection determination unit 4 to the management device C. Specifically, the communication unit 6 is input from the upstream disconnection determination unit 4 or the downstream disconnection determination unit 2, information indicating that a disconnection has occurred, information on the distribution line in which the disconnection has occurred, and The vectors ΔIa, ΔIb, ΔIc input from the downstream disconnection determination unit 2 are transmitted to the management apparatus C. Based on the information input from each disconnection detection device A, the management device C identifies the section where the disconnection has occurred. And it notifies that the disconnection occurred, the distribution line where the disconnection occurred, and the section where the disconnection occurred.

  The processing performed by each part of the disconnection detection device A may be designed by a program, and the computer may function as the disconnection detection device A by executing the program. The program may be recorded on a recording medium and read by a computer.

  Returning to FIG. 1, the management device C manages the state of the distribution line, and is realized by a dedicated computer, a general-purpose computer, or the like. The management device C receives information transmitted from each of the disconnection detection devices A1, A2, A3,. When the disconnection detecting devices A1, A2, A3,... Detect the disconnection, the information indicating that the disconnection has occurred, the information on the distribution line in which the disconnection has occurred, and the vectors ΔIa, ΔIb, ΔIc are transmitted to the management device C. Send. The management device C identifies the section where the disconnection has occurred based on the information received from each of the disconnection detection devices A1, A2, A3,. Then, the occurrence of the disconnection, the distribution line in which the disconnection has occurred, and the section in which the disconnection has occurred are displayed on a monitor screen or the like for notification. Note that a buzzer may warn that a disconnection has occurred.

  Since each disconnection detection device A includes the downstream disconnection determination unit 2 and the upstream disconnection determination unit 4, the disconnection direction can be estimated depending on which one detects the disconnection. However, when a distributed power source or a rotating machine is connected downstream of the disconnection position, even if a disconnection occurs upstream of the disconnection detection device A, the voltage on the downstream side of the disconnection position is maintained and the voltage changes , The upstream disconnection determination unit 4 may not be able to detect disconnection. On the other hand, even in this case, since the downstream disconnection determination unit 2 can detect the disconnection, it erroneously determines that the disconnection has occurred on the downstream side. In this case, if a section in which a disconnection occurs is specified based on incorrect information transmitted from each disconnection detection device A, it may be specified incorrectly. Therefore, in this embodiment, each disconnection detection device A does not determine the disconnection direction, and transmits the vectors ΔIa, ΔIb, ΔIc to the management device C, and the management device C transmits each disconnection detection device A1, A2, A3. ... Are identified based on the vectors ΔIa, ΔIb, ΔIc respectively input from. Hereinafter, the vectors ΔIa, ΔIb, ΔIc generated by the disconnection detecting device Ai (i = 1, 2, 3,...) And transmitted to the management device C are expressed as “vectors ΔIa (i), ΔIb (i), ΔIc (i ) ".

  The vectors ΔIa, ΔIb, ΔIc generated by the current change vector generation unit 1 of the disconnection detection device A differ depending on whether the disconnection occurs on the upstream side or on the downstream side. For example, as shown in FIG. 1, when disconnection occurs in the second section, the vectors ΔIa (1), ΔIb (1), ΔIc (1) generated by the disconnection detection device A1 and the disconnection detection device A2 are generated. The vectors ΔIa (2), ΔIb (2), ΔIc (2) to be generated are the same, but the vectors ΔIa (2), ΔIb (2), ΔIc (2) generated by the disconnection detecting device A2 The vectors ΔIa (3), ΔIb (3), and ΔIc (3) generated by the disconnection detection device A3 are different. FIG. 1 shows an example of vectors ΔIa, ΔIb, ΔIc generated by each of the disconnection detection devices A1, A2, A3, A4 when a disconnection occurs in the b-phase distribution line, and the vector ΔIa Is indicated by a solid line arrow, a vector ΔIb is indicated by a broken line arrow, and a vector ΔIc is indicated by a thick line arrow.

  The management device C receives vectors ΔIa, ΔIb, ΔIc input from the disconnection detection devices A1, A2, A3,..., Respectively, in order from the upstream side, and vectors ΔIa, ΔIb input from the disconnection detection device A adjacent to the downstream side. , ΔIc. When the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are determined to be different (not coincident), the two disconnections The section between the detection devices Ai and A (i + 1) is specified as the section where the disconnection has occurred. For example, in the case of the example of FIG. 1, the vectors ΔIa (1), ΔIb (1), ΔIc (1) input from the disconnection detection device A1 and the vectors ΔIa (2), ΔIb (2) input from the disconnection detection device A2. ), ΔIc (2), but the vectors ΔIa (2), ΔIb (2), ΔIc (2) input from the disconnection detection device A2 and the vector ΔIa (3) input from the disconnection detection device A3. , ΔIb (3), ΔIc (3), the management device C specifies that the second section between the disconnection detection device A2 and the disconnection detection device A3 is a section in which a disconnection has occurred.

Whether the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are similar or different is determined based on the degree of coincidence. The degree of coincidence is an index indicating how similar the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are. In the present embodiment, the management apparatus C calculates the degree of coincidence ρ based on the following equation (1).

  ABSa indicates the degree of coincidence between the magnitude of the vector ΔIa (i) and the magnitude of the vector ΔIa (i + 1), and is the smaller of the magnitude of the vector ΔIa (i) and the magnitude of the vector ΔIa (i + 1). Divided by the larger one. Therefore, 0 <ABSa ≦ 1, and when the magnitude of the vector ΔIa (i) matches the magnitude of the vector ΔIa (i + 1), ABSa = 1. Similarly, ABSb indicates the degree of coincidence between the magnitude of the vector ΔIb (i) and the magnitude of the vector ΔIb (i + 1), and 0 <ABSb ≦ 1, and the magnitude of the vector ΔIb (i) and the vector ΔIb. If the sizes of (i + 1) match, ABSb = 1. ABSc indicates the degree of coincidence between the magnitude of the vector ΔIc (i) and the magnitude of the vector ΔIc (i + 1), and 0 <ABSc ≦ 1, and the magnitude of the vector ΔIc (i) and the vector ΔIc ( If the sizes of i + 1) match, ABSc = 1.

The above equation (1) is calculated from the following equation (2). θa is a phase difference between the vector ΔIa (i) and the vector ΔIa (i + 1), and −1 ≦ cos θa ≦ 1. When the phase of the vector ΔIa (i) matches the phase of the vector ΔIa (i + 1), θa = 0 and cos θa = 1. On the other hand, when the phase of the vector ΔIa (i) and the phase of the vector ΔIa (i + 1) are shifted by 180 °, cos θa = −1. Similarly, θb is a phase difference between the vector ΔIb (i) and the vector ΔIb (i + 1), and −1 ≦ cos θb ≦ 1. When the phase of the vector ΔIb (i) matches the phase of the vector ΔIb (i + 1), θb = 0 and cos θb = 1. On the other hand, when the phase of the vector ΔIb (i) and the phase of the vector ΔIb (i + 1) are shifted by 180 °, cos θb = −1. Θc is a phase difference between the vector ΔIc (i) and the vector ΔIc (i + 1), and −1 ≦ cos θc ≦ 1. When the phase of the vector ΔIc (i) and the phase of the vector ΔIc (i + 1) coincide with each other, θc = 0 and cos θc = 1. On the other hand, when the phase of the vector ΔIc (i) and the phase of the vector ΔIc (i + 1) are shifted by 180 °, cos θc = −1. As can be seen from the following equation (2), the degree of coincidence ρ is obtained by multiplying the degree of coincidence of the vector size and the degree of coincidence of the phase for each phase, and adding the weights. The coincidence degree ρ is −1 ≦ ρ ≦ 1, and the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are completely coincident. Ρ = 1 and ρ = −1 when they are inverted (completely inconsistent).

Note that the formula for calculating the degree of matching ρ is not limited to this. A value for determining whether the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are the same or different is calculated. Anything to do. For example, focusing on the phase of each vector, the degree of coincidence ρ may be increased as the phase difference of the vector for each phase is closer to “0”. The following formula (3) calculates the degree of coincidence ρ by paying attention to the phase of each vector, and calculates the degree of coincidence of phases by dividing the inner product for each phase by the product of absolute values. The degree of coincidence ρ (−1 ≦ ρ ≦ 1) is calculated by taking the sum and dividing by 3.

Further, paying attention to the size of each vector, the degree of coincidence ρ may be increased as the difference in vector size for each phase is closer to “0”. The following equation (4) calculates the degree of coincidence ρ by paying attention to the size of each vector. The degree of coincidence of the vector size is calculated for each phase, and the sum of the three phases is calculated as 3. The degree of coincidence ρ (0 ≦ ρ ≦ 1) is calculated by dividing.

  However, when the degree of coincidence ρ is calculated only by the phase or when the degree of coincidence ρ is calculated only by the magnitude, the calculation of the degree of coincidence ρ is easy, but a threshold value is set for determining whether or not they coincide. Depending on how you do this, you may end up with a lot of wrong decisions. Therefore, it is desirable to calculate the degree of coincidence ρ in consideration of both the phase and the size. In this case, the degree of coincidence ρ as a whole vector can be calculated. For example, it is possible to suppress erroneous judgments that the two are the same when the sizes are similar but the phases are significantly different, or when the phases are similar but the sizes are completely different. Can do.

The following equation (5) calculates the degree of coincidence ρ by paying attention to both the phase and size of each vector. In the calculation of the degree of phase coincidence for each phase in the above equation (3), The degree of coincidence is multiplied (−1 ≦ ρ ≦ 1). In addition, said (1) Formula weights for every phase based on the ratio of the magnitude | size of each vector in following (5) Formula.

In addition, you may make it use the following (6) Formula which weighted for every phase in said (3) Formula.

Further, after the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are transformed into states that can be easily compared, the matching degree ρ is set. You may make it calculate. For example, vectors ΔIa (i), ΔIb (i), ΔIc (i) and vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are represented by three as shown in the following equations (7) and (8), respectively. Vectors ΔIαβ (i) and ΔIαβ (i + 1) obtained by phase-to-phase conversion (αβ conversion) may be calculated, and the degree of coincidence ρ (−1 ≦ ρ ≦ 1) may be calculated using the following equation (11). . The ΔIαβ (i) corresponds to the “first vector” of the present invention, and the ΔIαβ (i + 1) corresponds to the “second vector” of the present invention. In this case, after the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are transformed into one vector, the matching degree ρ is calculated. Therefore, the calculation of the degree of coincidence ρ becomes easy.

Instead of the above equation (9), the following equation (10) for calculating the degree of coincidence ρ focusing on the phase of the vector may be used. 11) Formula may be used. Further, the degree of coincidence ρ may be calculated by converting to another vector by a method other than the three-phase to two-phase conversion and using the vector after each conversion.

  Next, the management apparatus C determines whether or not the matching degree ρ is close to “1”. Specifically, it is compared with a predetermined threshold value X to determine whether it is greater than or equal to the threshold value X or less than the threshold value X. In the present embodiment, the threshold value X is, for example, “0.9”. If the degree of coincidence ρ is greater than or equal to the threshold value X, it is determined that the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) match. It is determined that the section between the two disconnection detection devices Ai, A (i + 1) is not a section where a disconnection has occurred, and the degree of coincidence is determined in the next section. On the other hand, when the degree of coincidence ρ is less than the threshold value X, the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are not matched. Judgment is made and the section between the two disconnection detecting devices Ai, A (i + 1) is specified as the section where the disconnection has occurred.

  The threshold value X is not limited to “0.9”. The degree of coincidence ρ is −1 ≦ ρ ≦ 1, and when ρ = 1, perfect coincidence, and when ρ = −1, complete coincidence. As the threshold value X is set to a larger value, it is less likely to be determined to match, and as the threshold value X is set to a smaller value, it is easier to determine that the values match. The threshold value X may be appropriately determined by experiment so that the correct judgment can be made as much as possible.

  Even in the disconnection detection device A arranged on the distribution line where the disconnection has occurred, the vectors ΔIa, ΔIb, ΔIc cannot be transmitted to the management device C if the disconnection is not detected. Even in this case, the management apparatus C can specify the section in which the disconnection occurs using the received vectors ΔIa, ΔIb, and ΔIc. For example, in the example of FIG. 1, even if the disconnection detection device A4 cannot detect the disconnection, the section where the disconnection has occurred can be specified. Even if the disconnection detecting device A3 cannot detect the disconnection, the vectors ΔIa (2), ΔIb (2), ΔIc (2) are compared with the vectors ΔIa (4), ΔIb (4), ΔIc (4). It can be specified that the disconnection has occurred in the second section or the third section. The management apparatus C assigns numbers (for example, i = 1, 2,..., N) in order from the upstream side to the disconnection detection apparatus A that has transmitted the vectors ΔIa, ΔIb, ΔIc, and detects disconnection with a smaller number. In order from the device A, the vectors ΔIa, ΔIb, ΔIc are compared with the disconnection detecting device A adjacent to the downstream side. N is the number of disconnection detection devices A that have transmitted the vectors ΔIa, ΔIb, ΔIc to the management device C.

  FIG. 11 is a flowchart for explaining the disconnection section specifying process performed by the management apparatus C. This process is started when information indicating that a disconnection has occurred is received from any of the disconnection detection devices A.

  First, vectors ΔIa, ΔIb, ΔIc transmitted from each disconnection detecting device A are received (S1). Numbers (i = 1, 2,..., N) are assigned in order from the upstream to the disconnection detecting device A that has received the vectors ΔIa, ΔIb, ΔIc. Then, the variable i is initialized to “1” (S2), and it is determined whether or not the variable i is smaller than the number N of disconnection detection devices A (S3). When the variable i is smaller than N (S3: YES), the vectors ΔIa (i), ΔIb (i), ΔIc (i) of the i-th disconnection detection device A and the vector ΔIa of the (i + 1) th disconnection detection device A The degree of coincidence ρ with (i + 1), ΔIb (i + 1), ΔIc (i + 1) is calculated based on the above equation (1), and it is determined whether or not it is close to “1” (S4). Specifically, it is determined whether or not the matching degree ρ is equal to or greater than the threshold value X. When the degree of coincidence ρ is close to “1” (S4: YES), the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc (i + 1) are one. If it is determined that it is correct, the variable i is incremented by 1, and the process returns to step S3 to perform the next comparison. Steps S3 to S5 are repeated until “NO” in step S3 or step S4.

  In step S4, when the degree of coincidence ρ is not close to “1” (S4: NO), the vectors ΔIa (i), ΔIb (i), ΔIc (i) and the vectors ΔIa (i + 1), ΔIb (i + 1), ΔIc ( i + 1) is determined not to match, and the disconnection section is specified to be between the i-th disconnection detection device A and the (i + 1) -th disconnection detection device A (S6).

  In step S3, when the variable i becomes N (S3: NO), the vectors ΔIa (N), ΔIb (N), ΔIc (N) of the Nth (most downstream) disconnection detecting device A are also on the upstream side. It coincides with the vectors ΔIa (N−1), ΔIb (N−1), ΔIc (N−1) of the disconnection detector A (that is, all the vectors ΔIa (i), ΔIb (i), ΔIc (i Therefore, the disconnection section is identified as being downstream of the Nth disconnection detection device A (S7).

  Note that the disconnection section specifying process performed by the management apparatus C is not limited to the above-described one. For example, the comparison may be performed according to a known search algorithm. That is, it is only necessary that the section in which the degree of matching ρ is less than the threshold value X can be specified.

  In the present embodiment, each disconnection detection device A transmits vectors ΔIa, ΔIb, ΔIc to the management device C when a disconnection is detected. Based on the vectors ΔIa, ΔIb, ΔIc received from each disconnection detection device A, the management device C identifies the section where the disconnection has occurred. When the management device C compares the vectors ΔIa, ΔIb, ΔIc received from the respective disconnection detection devices A with those of the adjacent disconnection detection device A and determines that they do not match, the two disconnection detection devices A The section between is identified as the section where the disconnection occurred. Therefore, the section where the disconnection occurs is more appropriate than the case where the configuration detecting the disconnection on the upstream side of each disconnection detection device A detects the disconnection or the configuration detecting the disconnection on the downstream side detects the disconnection. Can be specified.

  Further, the management device C calculates the degree of coincidence ρ based on the above equation (1). Since the above equation (1) calculates the degree of coincidence ρ for the entire vector in consideration of both the phase and the magnitude, it is possible to suppress misjudgment of coincidence. Accordingly, it is possible to suppress erroneously specifying the section where the disconnection has occurred. In addition, since the threshold value to be compared with the degree of coincidence ρ is set to a large value “0.9”, it is possible to suppress erroneously determining that they do not match but match.

  The management apparatus C, in order from the upstream side among the disconnection detection apparatuses A that have transmitted the vectors ΔIa, ΔIb, and ΔIc, until the matching degree ρ is determined to be less than the threshold value X, the disconnection detection apparatus A and its downstream in order. A match is determined for the vectors ΔIa, ΔIb, ΔIc received from the disconnection detecting device A adjacent to the side. Therefore, the section where the disconnection occurs can be identified more reliably.

  Moreover, the disconnection detection apparatus A arrange | positioned most upstream among the some disconnection detection apparatuses A is arrange | positioned at the electric power sending part of a substation. When a disconnection occurs in the distribution line, it means that a disconnection has occurred on the downstream side of the disconnection detection device A. Therefore, the vectors ΔIa, ΔIb, ΔIc generated by the disconnection detection device A are upstream of the disconnection position. It will be a thing. Therefore, the difference from the vectors ΔIa, ΔIb, ΔIc on the downstream side of the disconnection position can be determined, so that the section where the disconnection has occurred can be specified appropriately. Conversely, when a disconnection occurs upstream from the disconnection detection device A arranged on the most upstream side, the section in which the disconnection has occurred cannot be properly specified. That is, when the voltage applied to the load decreases except in the healthy phase, the current flowing through the load changes and is reflected as vectors ΔIa, ΔIb, and ΔIc. Therefore, the vectors ΔIa, ΔIb, ΔIc of each disconnection detection device A differ depending on the load capacity and type on the load side of the disconnection detection device. Usually, the vectors ΔIa, ΔIb, ΔIc generated by the disconnection detection device A arranged on the most upstream side do not match the vectors ΔIa, ΔIb, ΔIc generated by the disconnection detection device A arranged on the downstream side thereof. It is judged and the section between these is specified as the section where the disconnection occurred. In order to eliminate this misjudgment, the disconnection detection device A arranged on the most upstream side of the disconnection detection device A arranged on the upstream side is not connected to the substation. It is necessary to arrange in the power delivery unit.

  Further, the disconnection detection apparatus A can detect an upstream disconnection by the upstream disconnection determination unit 4 and can detect a downstream disconnection by the downstream disconnection determination unit 2. Therefore, the occurrence of disconnection can be detected more reliably than when disconnection in only one direction is detected.

  Further, the downstream disconnection determination unit 2 determines whether or not the current change vectors ΔIa, ΔIb, ΔIc of each phase voltage reference input from the current change vector generation unit 1 satisfy the above conditions (1) to (3). When all the conditions are satisfied, it is determined that a disconnection has occurred on the downstream side. Although it is difficult to distinguish between load fluctuations and downstream disconnections based on line current vectors, they can be distinguished by differences in current change vectors of each phase voltage reference. Therefore, erroneous detection due to load fluctuation can be suppressed in downstream disconnection detection.

  In this embodiment, the case where the instrument transformers PT1, PT2, and PT3 each detect the line voltage between the distribution lines has been described. However, the instrument transformers PT1, PT2, and PT3 each have a phase voltage of the distribution line. May be detected.

  In the present embodiment, the current change vectors ΔIa, ΔIb, ΔIc of each phase voltage reference are used to determine the occurrence of the disconnection on the downstream side, but the present invention is not limited to this. For example, each line voltage reference current change vector may be used. Alternatively, a current change vector based on a voltage obtained by adding a predetermined phase to each phase voltage (for example, a voltage obtained by shifting each phase voltage by 10 °) may be used. That is, a current change vector based on the reference voltage for each phase may be used.

  In the present embodiment, when each disconnection detection device A detects a disconnection, a case has been described in which the vectors ΔIa, ΔIb, ΔIc are transmitted to the management device C together with information indicating that a disconnection has occurred. It is not limited to this. For example, each disconnection detection device A transmits only information indicating that a disconnection has occurred to the management device C, and the management device C that has received information indicating that a disconnection has occurred transmits a command to each disconnection detection device A. Then, the vectors ΔIa, ΔIb, ΔIc may be collected.

  In the present embodiment, each disconnection detection device A has been described with respect to a case where the vectors ΔIa, ΔIb, ΔIc are transmitted to the management device C even when the upstream disconnection determination unit 4 detects a disconnection, but the present invention is not limited to this. . When the upstream disconnection determination unit 4 detects a disconnection, the vectors ΔIa, ΔIb, ΔIc may not be transmitted to the management apparatus C. In this case, the amount of information transmitted to the management apparatus C can be suppressed. Each disconnection detection device A may not include the upstream disconnection determination unit 4 and the effective value calculation unit 3.

  In the said 1st Embodiment, the case where the case where a two-phase load fluctuation arises was not assumed was demonstrated. Below, the case where the case where a two-phase load fluctuation arises is assumed is explained as a 2nd embodiment.

  First, vectors ΔIa, ΔIb, ΔIc at the time of two-phase load fluctuation when the connection of transformer B is a ΔΔ connection will be described.

FIG. 12A shows a two-phase load fluctuation and shows a state where the load Lab and the load Lca are disconnected. In this case, as is apparent from FIG.
Ia = 0
Ib = Ibc
Ic = −Ibc
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab−Ica) − (0) = Iab−Ica
ΔIb = (Ibc−Iab) − (Ibc) = − Iab
ΔIc = (Ica−Ibc) − (− Ibc) = Ica
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図１２（ｂ）は、二相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。図４（ｂ）に示す断線時のベクトル図において、αが「０」の場合、図１２（ｂ）と同じベクトル図になってしまう。 When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,

It becomes. FIG. 12B shows the vectors ΔIa, ΔIb, ΔIc when the two-phase load fluctuates. In the vector diagram at the time of the disconnection shown in FIG. 4B, when α is “0”, the vector diagram is the same as that in FIG.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of two-phase load fluctuation when the connection of transformer B is a ΔY connection will be described.

When the load Lab and the load Lca are disconnected and Iab = Ica = 0,
Ia = Ibc
Ib = Ibc
Ic = -2Ibc
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab + Ibc−2Ica) − (Ibc) = Iab−2Ica
ΔIb = (Ibc + Ica−2Iab) − (Ibc) = Ica−2Iab
ΔIc = (Ica + Iab−2Ibc) − (− 2Ibc) = Ica + Iab
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図１３（ａ）は、二相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。図１３（ａ）に示すベクトルであっても、上記条件（１）〜（３）をすべて満たしてしまう場合がある。 When the line current vector based on each phase voltage is set as I and the vectors γVa, γVb, and γVc are replaced with the vector I, respectively,

It becomes. FIG. 13A shows the vectors ΔIa, ΔIb, ΔIc when the two-phase load fluctuates. Even the vector shown in FIG. 13A may satisfy all of the above conditions (1) to (3).

  Next, vectors ΔIa, ΔIb, ΔIc at the time of two-phase load fluctuation when the connection of transformer B is a YΔ connection will be described.

When the load Lab and the load Lca are disconnected and Iab = Ica = 0,
Ia =-(1/3) Ibc
Ib = (2/3) Ibc
Ic =-(1/3) Ibc
It becomes.

となる。 Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = ((2/3) Iab− (1/3) Ibc− (1/3) Ica) − (− (1/3) Ibc)
= (2/3) Iab- (1/3) Ica
ΔIb = ((2/3) Ibc− (1/3) Ica− (1/3) Iab) − (2/3) Ibc
=-(1/3) Ica- (1/3) Iab
ΔIc = ((2/3) Ica− (1/3) Iab− (1/3) Ibc) − (− (1/3) Ibc)
= (2/3) Ica- (1/3) Iab
And expressed with reference to the phase voltage vector of each phase,

It becomes.

となる。図１３（ｂ）は、二相負荷変動時のベクトルΔＩａ，ΔＩｂ，ΔＩｃを示したものである。図１３（ｂ）に示すベクトルであっても、上記条件（１）〜（３）をすべて満たしてしまう場合がある。 When the line current vector based on each phase voltage is set to I and the vectors εVa, εVb, and εVc are replaced with the vector I, respectively,

It becomes. FIG. 13B shows the vectors ΔIa, ΔIb, ΔIc when the two-phase load fluctuates. Even the vector shown in FIG. 13B may satisfy all of the above conditions (1) to (3).

  As described above, if occurrence of disconnection is determined under the above conditions (1) to (3), it is erroneously determined as disconnection when the two-phase load fluctuates. In the second embodiment, no erroneous determination is made in the case of a two-phase load fluctuation.

  FIG. 14 is a diagram for explaining the disconnection detection device A ′ according to the second embodiment. In the figure, the same or similar elements as those in the disconnection detection apparatus A (see FIG. 2) according to the first embodiment are denoted by the same reference numerals.

  The disconnection detection device A ′ shown in FIG. 14 is the same as the first embodiment in that the downstream disconnection determination unit 2 ′ uses the input from the zero-phase voltage sensor 7 to determine whether the downstream disconnection has occurred. It differs from the disconnection detection apparatus A which concerns.

  The zero phase voltage sensor 7 is disposed on the distribution lines a, b, and c, and detects the zero phase voltage. The zero-phase voltage sensor 7 outputs the detected zero-phase voltage to the downstream disconnection determination unit 2 '.

The downstream disconnection determination unit 2 ′ also determines the occurrence of disconnection using the zero phase voltage input from the zero phase voltage sensor 7. Specifically, the downstream disconnection determination unit 2 ′ sets the following condition (4) in addition to the above conditions (1) to (3).
(4) The zero-phase voltage is equal to or higher than a predetermined threshold value V ₀ .

The zero-phase voltage is “0” in the three-phase equilibrium state, and is not affected by the load fluctuation. However, when a disconnection occurs, an unbalanced state occurs and the zero-phase voltage is not “0”. When the zero-phase voltage is equal to or higher than a predetermined threshold value V ₀ based on detection errors, a disconnection may have occurred. In the present embodiment, for example, a value of several volts is set as the predetermined threshold value V ₀ . Since the zero phase voltage may not be “0” due to the unbalance due to the fluctuation of the power system, the condition (1) to (3) is not determined based on the condition (4) alone. Judgment is also made. The downstream disconnection determination unit 2 ′ determines that a disconnection has occurred in the distribution line when all of the above conditions (1) to (4) are satisfied.

  When the two-phase load fluctuates, the above conditions (1) to (3) may be satisfied, but the above condition (4) is not satisfied. Therefore, in the second embodiment, it is possible to suppress erroneous determination that disconnection occurs when the two-phase load fluctuates.

  In the first and second embodiments, the case where the downstream disconnection is detected based on the current change vector has been described. However, the method for detecting the downstream disconnection is not limited to this. For example, the downstream disconnection may be detected based on the current vector. Further, a disconnection on the downstream side may be detected based on a change in impedance.

  In the first and second embodiments, the case where the upstream disconnection is detected based on the effective value of the line voltage has been described, but the method of detecting the upstream disconnection is not limited to this. For example, the upstream disconnection may be detected based on the instantaneous value of the line voltage. Further, a phase voltage may be used instead of the line voltage. Further, the disconnection on the upstream side may be detected using current, power, zero-phase voltage, or the like instead of voltage.

  In the first and second embodiments, the case where the disconnection detection device A (A ′) can detect both the upstream disconnection and the downstream disconnection has been described. However, the present invention is not limited to this. The disconnection detecting device A (A ′) may detect only one of the upstream and downstream disconnections. That is, the disconnection detection device A (A ′) may be any device that can detect that a disconnection has occurred. Even in this case, when the disconnection occurs, the management device C can identify the section where the disconnection has occurred.

  The disconnection section specifying system and the disconnection section specifying method according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the disconnection section specifying system and the disconnection section specifying method according to the present invention can be varied in design in various ways.

A, A ′, A1, A2, A3, A4 Disconnection detection device 1 Current change vector generation unit 11 Vector generation unit 12 Calculation unit 13 Storage unit 2, 2 ′ Downstream disconnection determination unit (disconnection determination unit)
3 RMS value calculation unit 4 Upstream disconnection determination unit (disconnection determination means)
5 Shut-off command section 6 Communication section 7 Zero phase voltage sensor a, b, c Distribution line CT1, CT2, CT3 Current transformer (electric signal detector)
PT1, PT2, PT3 Instrument transformer (electric signal detector)
B Transformer C Management device (calculation means, determination means)
D Substation

Claims (14)

A plurality of disconnection detection devices that are arranged on a three-phase distribution line and detect that any disconnection of the three-phase distribution line has occurred,
A management device for managing the plurality of disconnection detection devices;
With
The disconnection detection device includes:
A current change vector generating means for generating a current change vector, which is a change vector of a line current vector based on a reference voltage for each phase, based on an electrical signal detected by an electrical signal detector disposed on the distribution line;
A disconnection determining means for determining whether a disconnection has occurred in the distribution line;
Communication means for transmitting each current change vector generated by the current change vector generating means to the management device when it is determined by the disconnection determining means that a disconnection has occurred;
The management device comprises
By comparing the current change vectors received from each of the disconnection detection devices, the section where the disconnection occurred is specified.
The disconnection section identification system characterized by this. The management device
Calculating means for calculating a degree of coincidence between a current change vector received from a certain disconnection detecting device and a current change vector received from another of the disconnection detecting devices;
A determination unit that determines that a disconnection has occurred in a section between the two disconnection detection devices when the degree of coincidence calculated by the calculation unit is less than a predetermined threshold;
With
The disconnection section identification system according to claim 1. The management device, in order from the upstream side among the disconnection detection devices that have transmitted the current change vector, until the determination unit determines that the degree of coincidence is less than a predetermined threshold, For the current change vector received from the disconnection detection device adjacent to the downstream side, the degree of coincidence is calculated by the calculation means.
The disconnection section identification system according to claim 2. The disconnection detection device arranged on the most upstream side among the plurality of disconnection detection devices is arranged in the power delivery part of the substation,
The disconnection section identification system according to claim 2 or 3. The degree of coincidence is calculated based on the phase difference of each phase of the two current change vectors.
The disconnection section identification system according to any one of claims 2 to 4. The degree of coincidence is calculated based on the difference in magnitude of each phase of the two current change vectors.
The disconnection section identification system according to any one of claims 2 to 4. Ρ that is the degree of coincidence is that one of the current change vectors is ΔIa (i), ΔIb (i), ΔIc (i), and the other current change vector is ΔIa (i + 1), ΔIb (i + 1), ΔIc ( i + 1) is calculated based on the following equation:
The disconnection section identification system according to any one of claims 2 to 4.

The threshold is “0.9”.
The disconnection section identification system according to claim 7. The calculation means transforms one of the current change vectors into a first vector, transforms the other current change vector into a second vector, and based on the first vector and the second vector , Calculating the degree of coincidence,
The disconnection section identification system according to any one of claims 2 to 4. Ρ that is the degree of coincidence is that one of the current change vectors is ΔIa (i), ΔIb (i), ΔIc (i), and the other current change vector is ΔIa (i + 1), ΔIb (i + 1), ΔIc ( i + 1) is calculated based on the following equation:
The disconnection section identification system according to claim 9.

The current change vector generation means includes
Vector generating means for generating a line current vector for each phase based on the current signal detected by the electrical signal detector, and generating a voltage vector for each phase based on the voltage signal detected by the electrical signal detector;
Calculation means for converting the line current vector of each phase into a vector based on a reference voltage for each phase using the voltage vector of each phase and calculating a change vector of the line current vector of each phase after the conversion When,
With
The disconnection section identification system according to any one of claims 1 to 10. The disconnection judging means has each current change vector generated by the current change vector generating means,
(1) A phase difference of a current change vector of a phase whose phase advances with respect to a current change vector of a certain phase, and a current change vector of the certain phase with respect to a current change vector of a phase whose phase is later than the certain phase Of the first threshold value θ ₁ or more and the second threshold value θ ₂ or less, respectively.
(2) the magnitudes of all current change vectors are greater than or equal to a predetermined threshold I ₀ ;
(3) Not applicable when all of the following (3-1) to (3-2) are satisfied,
(3-1) The phase difference between the current change vector having the maximum size among the current change vectors and the other current change vectors is about 60 °, respectively.
(3-2) The magnitude of the maximum current change vector is about twice the magnitude of the other current change vectors.
If all the conditions are satisfied, it is determined that a disconnection has occurred.
The disconnection section identification system according to any one of claims 1 to 11. It further comprises a zero phase voltage detecting means for detecting a zero phase voltage,
In addition to the conditions (1) to (3), the disconnection determination means
(4) The zero-phase voltage is not less than a predetermined threshold value V ₀ .
If all the conditions are satisfied, it is determined that a disconnection has occurred.
The disconnection section identification system according to claim 12. A plurality of disconnection detection devices that are arranged on a three-phase distribution line and detect that any disconnection of the three-phase distribution line has occurred,
A management device for managing the plurality of disconnection detection devices;
A method for identifying a section where disconnection has occurred in a system comprising
Each disconnection detection device generates a current change vector, which is a change vector of a line current vector based on a reference voltage for each phase, based on an electrical signal detected by an electrical signal detector disposed on the distribution line. A first step;
A second step in which each of the disconnection detection devices determines whether or not a disconnection has occurred in the distribution line based on each current change vector generated in the first step;
A third step of transmitting each current change vector generated by the first step to the management device when it is determined that the disconnection has occurred by the second step;
A fourth step in which the management device identifies a section in which a disconnection occurs by comparing the current change vectors received from the disconnection detection devices;
The disconnection section identification method characterized by comprising.

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