JP2009077566A - Variable composite current transformer and protective relay device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable composite current transformer enabling further reduction of the installation number of current transformers and short circuit protective relays which are used to protect a three-phase AC circuit from a short circuit failure, and to provide a protective relay device. <P>SOLUTION: The variable composite current transformer 10 composites currents to be inputted from first-third current transformers 3<SB>1</SB>-3<SB>3</SB>respectively provided on R-phase, S-phase and T-phase of a power transmission line at a composite current ratio (-0.5:0.5):-1.5. Upon detecting a short circuit failure on the basis of a short circuit current I<SB>Ry</SB>inputted from the variable composite current transformer 10, an overcurrent relay 4 collectively interrupts first-third breakers 2<SB>1</SB>-2<SB>3</SB>installed in the R-phase, S-phase and T-phase of the power transmission line. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable composite current transformer and a protective relay device, and more particularly to a variable composite current transformer suitable for reducing the number of installed current transformers and short circuit protection relays for protecting a three-phase AC circuit from a short circuit accident. The present invention relates to a current drain and a protective relay device.

  Conventionally, in a three-phase AC circuit, an overcurrent relay (OC) is installed for each phase in order to protect the three-phase AC circuit from a short circuit accident (see, for example, Patent Document 1 below).

Moreover, in the power transmission / distribution line of the terminal circuit, etc., the short circuit current flows in two phases, and an overcurrent relay is installed only in the two phases to reduce the equipment cost. For example, as shown in FIG. 23, first and second current transformers (CT) 3 ₁ , 3 ₂ respectively installed in the R phase and the T phase among the R phase, S phase, and T phase of the transmission and distribution line. When the first and second overcurrent relays (OC) 4 ₁ , 4 ₂ are connected to each other and a short-circuit accident occurs in the transmission / distribution line, the transmission / distribution line depends on the aspect of the accident as shown below. The _first to _third circuit breakers 2 ₁ to 2 ₃ installed in the R phase, the S phase, and the T phase, respectively, are collectively disconnected by the first and second overcurrent relays 4 ₁ and 4 ₂ .
(1) In the case of a short-circuit accident between the R phase and the S phase Since a short circuit current flows in the R phase and S phase of the transmission and distribution line, the short circuit current input from the _first current transformer 31 installed in the R phase Based on this, the first overcurrent relay 4 ₁ operates to collectively shut off the _first to _third circuit breakers 2 ₁ to 2 ₃ .
(2) In the case of a short-circuit accident between S-phase and T-phase Since a short-circuit current flows in the S-phase and T-phase of the transmission and distribution line, the short-circuit current input from the _second current transformer 3 ₂ installed in the T-phase Based on this, the second overcurrent relay 4 ₂ operates to cut off the _first to _third circuit breakers 2 ₁ to 2 ₃ at _once .
(3) In the case of a short circuit accident between the T phase and the R phase Since a short circuit current flows in the R phase and the T phase of the transmission and distribution line, the first and second current transformers 3 ₁ installed in the R phase and the T phase, respectively. , 3 ₂ , the first and second overcurrent relays 4 ₁ , 4 ₂ operate based on the short-circuit currents respectively input from the _first to _third circuit breakers 2 ₁ to 2 ₃ .
(4) In the case of a short circuit accident between the R phase, the S phase, and the T phase Since a short circuit current flows in the R phase, the S phase, and the T phase, the first and second current transformers installed in the R phase and the T phase, respectively. The first and second overcurrent relays 4 ₁ and 4 ₂ operate on the basis of the short-circuit currents input from 3 ₁ and 3 ₂ , respectively, and collectively cut off the _first to _third circuit breakers 2 ₁ to 2 _3. .
JP-A-8-005659

  However, since three or two current transformers and overcurrent relays are installed for each transmission / distribution line, a request to further reduce the installation cost by reducing the number of current transformers and overcurrent relays installed. There is.

  Such a request is a current differential relay for protecting a three-phase AC circuit from a short-circuit accident inside the transformer, and an overcurrent protection relay used for protecting the three-phase AC circuit from a short-circuit accident in the premises. Current detection, pulse code modulation current differential relay (PCM current differential relay) used on the power supply bus side and power receiving end bus side of the transmission / distribution line, and the current detection sensitivity is corrected according to the voltage value There is also an overcurrent relay with voltage suppression and the like having a function to perform.

  An object of the present invention is to provide a variable composite current transformer and a protective relay device that can further reduce the number of installed current transformers and short circuit protection relays for protecting a three-phase AC circuit from a short circuit accident. is there.

The variable composite current transformer of the present invention is a variable composite current transformer for detecting a short-circuit current flowing in the first to third phases of the three-phase AC circuit, and flows in the first to third phases. The short-circuit current is synthesized at a synthetic current ratio ± x ₁ : ± x ₂ : ± x ₃ (x ₁ , x ₂ , x ₃ > 0).
The variable composite current transformer of the present invention is a variable composite current transformer (10, 10 ₁ , 10 ₂ ) for detecting a short-circuit current flowing in the first to third phases of the three-phase AC circuit. The short-circuit current flowing in the first to third phases is the combined current ratio x ₁ : x ₂ : x ₃ , the combined current ratio x ₁ : −x ₂ : x ₃ or the combined current ratio −x ₁ : x ₂ : − It is characterized by being synthesized by x ₃ (x ₁ , x ₂ , x ₃ > 0).
Here, arithmetic processing means for determining the accident aspect of the short-circuit accident of the three-phase AC circuit and multiplying the short-circuit current detected by the variable composite current transformer by a predetermined multiple according to the determination result of the accident aspect. You may prepare.
The protective relay device of the present invention is a protective relay device for protecting a three-phase AC circuit from a short circuit accident, and includes the variable composite current transformer of the present invention and a short circuit input from the variable composite current transformer. When a short-circuit accident is detected based on the current, a short-circuit protective relay is provided that collectively shuts off the circuit breakers installed in the first to third phases of the three-phase AC circuit.
Here, the protective relay device includes an accident mode determination unit that determines an accident mode of a short circuit accident of the three-phase AC circuit, and an accident in the accident mode determination unit that detects a short circuit current detected by the variable composite current transformer. You may further comprise the arithmetic processing means which multiplies the predetermined multiple according to the determination result of an aspect.
The accident mode determination means determines whether the three-phase AC circuit has three line voltages (V _RS , V _ST , V _TR ), three phase voltages (V _R , V _S , V _T ) or a phase / line voltage. Based on this, the accident aspect of the short circuit accident of the three-phase AC circuit may be determined.
The accident mode determination means is based on the voltage value and phase of one line voltage (V _RS , V _ST , V _TR ) and one phase voltage (V _R , V _S , V _T ) of the three-phase AC circuit. Thus, the accident aspect of the short circuit accident of the three-phase AC circuit may be determined.
The accident mode judging means is configured to _detect a voltage value and a phase of one line voltage (V _RS , V _ST , V _TR ) of the three-phase AC circuit and a short circuit current (I _Ry ) input from the variable composite current transformer. The accident aspect of the short circuit accident of the three-phase AC circuit may be determined based on the phase of the three-phase AC circuit.
The first phase voltage (V _R ) of the three-phase AC circuit is in the polarity direction, and the second phase voltage (V _S ) of the three-phase AC circuit is in the opposite polarity direction. The first to second phases are used for determining the accident aspect of the short-circuit fault of the three-phase AC circuit, where the secondary side is connected so as to synthesize the phase voltage (V _T ) by doubling in the opposite polarity direction. An accident mode judging transformer (110) for obtaining a composite voltage (V _RS-2T ) of the phase voltages of the three phases, wherein the accident mode judging means is inputted from the accident mode judging transformer. The accident aspect of the short circuit accident of the three-phase AC circuit may be determined based on the voltage value and phase of the combined voltage and the phase of the short circuit current (I _Ry ) input from the variable combined current transformer.
The first phase voltage (V _R ) of the three-phase AC circuit is in the polarity direction, and the second phase voltage (V _S ) of the three-phase AC circuit is in the opposite polarity direction. The first to third are used to determine the accident aspect of the short-circuit accident of the three-phase AC circuit in which the secondary side is connected so that the phase voltage (V _T ) is doubled and synthesized in the polarity direction. And an accident mode judging transformer (120) for obtaining a composite voltage (V _{R-S + 2T} ) of the above _-mentioned phase voltage, and the accident mode judging means is inputted from the accident mode judging transformer The accident aspect of the short circuit accident of the three-phase AC circuit may be determined based on the voltage value and phase of the combined voltage and the phase of the short circuit current (I _Ry ) input from the variable combined current transformer.
The first phase voltage (V _R ) of the three-phase AC circuit is multiplied by a in the polarity direction or the antipolar direction, and the second phase voltage (V _S ) of the three-phase AC circuit is changed in the polarity direction or antipolar direction. And the secondary side is connected so that the third phase voltage (V _T ) of the three-phase AC circuit is multiplied by c in the polarity direction or the opposite polarity direction to be combined, and the three-phase AC A _fault condition determining transformer for obtaining a composite voltage (V _{aR + bS + cT} ) of the first to third phase voltages used for determining an accident aspect of a circuit short-circuit accident; The aspect determination means is configured to _{select the} three-phase based on the voltage value and phase of the combined voltage input from the accident aspect determination transformer and the phase of the short circuit current (I _Ry ) input from the variable combined current transformer. You may determine the accident aspect of the short circuit accident of an AC circuit.
The variable synthesis current transformer synthesizes the currents input from the _first to _third current transformers (31 to 3 ₃ ) installed in the first to third phases of the transmission and distribution lines, respectively. When the short circuit protection relay detects a short circuit fault based on the short circuit current (I _Ry ) input from the variable composite current transformer, the first through first of the transmission and distribution lines The overcurrent relay (4) which interrupts | blocks the _1st thru | or 3rd circuit breakers (2 ₁ to 2 ₃ ) respectively installed in the three phases at once may be used.
The variable composite current transformer is input from _first to _third current transformers (3 _{1 to} 3 ₃ ) installed in the first to third phases on the primary side of the transformer (5), respectively. A first variable current transformer (10 ₁ ) for combining currents, and fourth to sixth current transformers (3) installed in the first to third phases on the secondary side of the transformer, respectively. _{4 to} 3 ₆ ) and a second variable composite current transformer (10 ₂ ) for synthesizing the current input from the first variable composite current transformer. And a short-circuit fault is detected based on the difference between the short-circuit current input from the second variable composite current transformer and the first to third phases on the primary side of the transformer are respectively installed. shielding of the first to fourth to sixth placed respectively in the third circuit breaker (2 ₁ to 2 ₃₎ and the first to third secondary side of the transformer phase Vessels may be (2 _{4-2 6)} and the current differential relay for collectively blocking (20).
The variable composite current transformer is input from _first to _third current transformers (3 _{1 to} 3 ₃ ) installed in the first to third phases of the first transmission and distribution line (1L), respectively. The first variable current transformer (10 ₁ ) for synthesizing currents and the fourth to sixth current transformers installed in the first to third phases of the second transmission / distribution line (2L), respectively. (3 _{4 to} 3 ₆ ) and a second variable composite current transformer (10 ₂ ) for synthesizing the current input from the first variable composite current transformer. When a short-circuit fault is detected based on the sum current of the short-circuit current and the short-circuit current input from the second variable composite current transformer, it is installed in each of the first to third phases of the first transmission and distribution line. the first to fourth to sixth disposed respectively in the third circuit breaker (2 ₁ to 2 ₃₎ and said first to third second transmission and distribution lines of the phases were Breaker (2 _{4-2 6)} and a may be a overcurrent relay for collectively blocking (30).
Current input from the _first to _third current transformers (3 _{1 to} 3 ₃ ) installed in the first to third phases of the transmission / distribution line on the power supply end bus side of the variable composite current transformer A first variable current transformer (10 ₁ ) for synthesizing the power supply, and fourth to sixth current transformers (10 ₁ ) installed in the first to third phases of the transmission and distribution lines on the power receiving end bus side ( 3 _{4 to} 3 ₆ ) and a second variable composite current transformer (10 ₂ ) for synthesizing the current input from the first variable composite current transformer. When a short-circuit fault is detected based on the difference between the current and the short-circuit current input from the second variable composite current transformer, the first to third phases of the transmission and distribution lines on the power supply end bus side are respectively detected. it the first to third circuit breaker (2 ₁ to 2 ₃₎ and the first to third electric transmission of the receiving end bus side of the phase installed The installed fourth to sixth breaker (2 _{4-2 6)} and the or a first and second pulse code modulated current differential relay for collectively blocking respectively (60 _1, 60 _2).
The variable synthesis current transformer synthesizes the currents input from the _first to _third current transformers (31 to 3 ₃ ) installed in the first to third phases of the transmission and distribution lines, respectively. A current transformer (10), in which the short-circuit protective relay is configured such that a short-circuit current (I _Ry ) input from the variable composite current transformer and a line voltage (V _RS , V _ST , V _TR ) When a short circuit accident is detected based on the suppression voltage (V _Ry ) calculated using the first to third circuit breakers (2 ₁ ) installed in the first to third phases of the transmission and distribution line, respectively. The overcurrent relay (50) with a voltage suppression which cuts off -2 ₃ ) collectively may be sufficient.

The variable composite current transformer and the protective relay device of the present invention have the following effects.
(1) The currents respectively input from the first to third phases of the three-phase AC circuit are combined current ratios ± x ₁ : ± x ₂ : ± x ₃ (for example, combined current ratio −x ₁ : x ₂ : − Installation of current transformers and short-circuit protection relays to protect three-phase AC circuits from short-circuit accidents by using variable composite current transformers that are synthesized with x ₃ or composite current ratio x ₁ : x ₂ : x ₃ ) The number of units can be further reduced to reduce the equipment cost.
(2) Although the amplitude of the short-circuit current output from the variable composite current transformer varies depending on the accident aspect of the short-circuit accident, the detection sensitivity and operation of the short-circuit protective relay can be adjusted by adjusting or correcting the amplitude of the short-circuit current according to the accident aspect. The time can be the same.
(3) By changing the composite current ratio, it is possible to synthesize a short-circuit current having an arbitrary magnitude and phase necessary for relay determination.

For the above purpose, the short-circuit current flowing in the first to third phases of the three-phase AC circuit is synthesized with the synthesized current ratio -x ₁ : x ₂ : -x ₃ or the synthesized current ratio x ₁ : x ₂ : x ₃ . When the short circuit protection relay detects a short circuit accident based on the short circuit current input from the variable composite current transformer, the variable composite current transformer is installed in the first to third phases of the three-phase AC circuit. This was realized by shutting off the circuit breakers at once.

Hereinafter, embodiments of the variable composite current transformer and the protective relay device of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the protective relay device according to the first embodiment of the present invention includes a variable composite current transformer 10 and a transmission / distribution line based on a short circuit current I _Ry input from the variable composite current transformer 10. When the short circuit accident is detected, the overcurrent relay 4 is provided that collectively shuts off the _first to _third circuit breakers 2 ₁ to 2 ₃ installed in the R phase, S phase, and T phase of the transmission and distribution lines.

Here, the variable composite current transformer 10 combines the currents input from the _first to _third current transformers 3 ₁ to ₃ 3 installed in the R-phase, S-phase, and T-phase of the transmission and distribution lines, respectively. For synthesis at a ratio of -0.5: 0.5: -1.5. As a result, the variable composite current transformer 10 reverses the polarity of the current flowing through the R phase of the power transmission and distribution line by 0.5 times, and the current flowing through the S phase by 0.5 times and the T phase. The sum of the current and the current multiplied by 1.5 is output by inverting the polarity of the flowing current.

Therefore, when the load currents flowing in the R-phase, S-phase, and T-phase of the transmission and distribution line when no short-circuit accident has occurred are represented by I _R , I _S , and I _T , the variable current transformer 10 can be used as an overcurrent relay. As shown in FIG. 2 (a), the load current I input to 4 is a current obtained by multiplying the negative-phase R-phase load current I _R by 0.5 (= −0.5I _R ) and the S-phase load current I _R. the vector sum of the current (= -1.5I _T) polarity and the load current I _S to 0.5 times the current (= 0.5I _S) was 1.5 times the load current I _T of the negative T-phase However, since the R-phase load current I _R , the S-phase load current I _S and the T-phase load current I _T are out of phase by 120 °, the amplitude of the load current I is R-phase load current. It becomes 3 ^1/2 times the amplitude of I _R (S-phase and T-phase load currents I _S , I _T ).
I = −0.5I _R + 0.5I _S −1.5I _T
| I | = | −0.5I _R + 0.5I _S −1.5I _T |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _R |
= 3 ^1/2 × | I _R | (= 3 ^1/2 × | I _S | = 3 ^1/2 × | I _T |)

Moreover, when the short circuit current flowing in the R phase, S phase, and T phase of the transmission / distribution line is represented by I _FR , I _FS , I _FT when a short circuit accident occurs in the transmission / distribution line, the variable composite current transformer 10 causes excessive current. The short-circuit current I _Ry input to the current relay 4 is expressed as follows according to the accident aspect, where θ is the impedance angle of the short-circuit currents I _FR , I _FS , and I _FT .
(1) In the case of a short circuit accident between the R phase and the S phase When a short circuit accident between the R phase and the S phase occurs, the short circuit current I _FR of the R phase is generated in the R phase of the transmission and distribution line as shown by the broken arrow in FIG. flow inside direction, but the short-circuit current I _FS of S phase to the S phase of the transmission and distribution lines to flow to the outside direction, the T-phase of the transmission and distribution lines does not flow a short-circuit current I _FT T-phase.
Therefore, the short-circuit current I _Ry output from the variable composite current transformer 10 to the overcurrent relay 4 is a current (= −0.5I _FR ) obtained by multiplying the R-phase short-circuit current I _FR having a negative polarity by 0.5. Although the vector sum of the phase of the short-circuit current I _FS 0.5 times the current (= 0.5I _FS), the phase difference between the short-circuit current I _FS of the short circuit current I _FR and S phases of the R phase is 180 ° Therefore, the amplitude of the short-circuit current I _{Ry is} the amplitude of the S-phase short-circuit current I _FS (R-phase short-circuit current I _FR ) as shown in FIG.
I _Ry = −0.5 I _FR +0.5 I _FS = 0.5 (I _FS −I _FR )
| I _Ry | = | 0.5 (I _FS −I _FR ) | = | I _FS | (= | I _FR |)
In FIGS. 3 and 4, short-circuit currents I _FR , I _FS , I _FT flowing in the inner direction of the transmission / distribution line are solid arrows, and short-circuit currents I _FR , I _FS , I _FT is indicated by a dashed-dotted arrow.
(2) In the case of a short circuit accident between the S phase and the T phase When a short circuit accident occurs between the S phase and the T phase, the short circuit current I _FS of the S phase is generated in the S phase of the power transmission and distribution line as shown by the broken arrow in FIG. flow inside direction, but the short-circuit current I _FT T-phase to the T phase of the transmission and distribution lines to flow to the outside direction, the R-phase of the transmission and distribution lines does not flow a short-circuit current I _FR of R-phase.
Therefore, the short-circuit current I _Ry output from the variable composite current transformer 10 to the overcurrent relay 4 is a current obtained by multiplying the S-phase short-circuit current I _FS by 0.5 (= 0.5 I _FS ) and the T-phase having a negative polarity. Is a vector sum of a current obtained by multiplying the short-circuit current I _FT by 1.5 (= −1.5 I _FT ), but the phase difference between the S-phase short-circuit current I _FS and the T-phase short-circuit current I _FT is 180 °. Therefore, the amplitude of the short-circuit current I _Ry is twice the amplitude of the S-phase short-circuit current I _FS (T-phase short-circuit current I _FT ) as shown in FIG.
I _Ry = 0.5I _FS -1.5I _FT
| I _Ry | = | 0.5 I _FS −1.5 I _FT | = 2 × | I _FS | (= 2 × | I _FT |)
(3) In the case of a short circuit accident between the T phase and the R phase When a short circuit accident occurs between the T phase and the R phase, the short circuit current I _FT of the T phase is applied to the T phase of the transmission and distribution line as shown by the broken arrow in FIG. flow inside direction, but the short-circuit current I _FR of R-phase to R-phase of transmission and distribution lines to flow to the outside direction, the S-phase of the transmission and distribution lines does not flow a short-circuit current I _FS of S phase.
Therefore, the short-circuit current I _Ry output from the variable composite current transformer 10 to the overcurrent relay 4 has a current (= −0.5 I _FR ) and a polarity that is 0.5 times the R-phase short-circuit current I _FR having a negative polarity. Is the vector sum of the negative T-phase short-circuit current I _FT multiplied by 1.5 (= −1.5 I _FT ), but the R-phase short-circuit current I _FR and the T-phase short-circuit current I _FT Since the phase difference is 180 °, the amplitude of the short-circuit current I _{Ry is} the amplitude of the R-phase short-circuit current I _FR (T-phase short-circuit current I _FT ) as shown in FIG.
I _Ry = −0.5 I _FR −1.5 I _FT = − (0.5 I _FR +1.5 I _FT )
| I _Ry | = | 0.5 I _FR +1.5 I _FT | = | I _FR | (= | I _FT |)
(4) In the case of a short circuit accident between R phase, S phase, and T phase When a short circuit accident between R phase, S phase, and T phase occurs, the R phase and S phase of the power transmission and distribution line as shown by the dashed arrows in FIG. In addition, an R-phase short-circuit current I _FR , an S-phase short-circuit current I _FS, and a T-phase short-circuit current I _FT flow in the internal direction with a phase difference of 120 °, respectively.
Therefore, the short-circuit current I _Ry output from the variable composite current transformer 10 to the overcurrent relay 4 is a current (= −0.5I _FR ) obtained by multiplying the R-phase short-circuit current I _FR having a negative polarity by 0.5. vector between the current (= 0.5I _FS) and current polarities are 1.5 times the short-circuit current I _FT negative T-phase (= -1.5I _FT) that the short-circuit current I _FS phases were 0.5 times Although the sum, since the short-circuit current I _FR of R-phase, short-circuit current I _FT circuit current I _FS and T phases of the S phase is the phase with at 120 ° intervals, the amplitude of the short-circuit current I _F1 is 4 ( As shown in a), the amplitude is 3 ^1/2 times the amplitude of the R-phase short-circuit current I _FR (S-phase and T-phase short-circuit currents I _FS and I _FT ).
I _Ry = −0.5 I _FR +0.5 I _FS −1.5 I _FT
| I _Ry | = | −0.5 I _FR +0.5 I _FS −1.5 I _FT |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _FR |
= 3 ^1/2 × | I _FR | (= 3 ^1/2 × | I _FS | = 3 ^1/2 × | I _FT |)

When the amplitude of the short circuit current I _Ry exceeds the current set value, the overcurrent relay 4 determines that a short circuit accident has occurred in the transmission and distribution lines, and the _first to _third circuit breakers 2 ₁ to 2 _3. Block all at once.

In the variable composite current transformer 10, the composite current ratio of the currents input from the _first to _third current transformers 3 _{1 to} 3 ₃ is “−0.5: 0.5: −1.5”. Are "-0.5: -1.5: 0.5", "0.5: -0.5: -1.5", "0.5: -1.5: -0.5", It may be “−1.5: 0.5: −0.5” or “−1.5: −0.5: 0.5”.

Next, a protective relay device according to a second embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 9, the protective relay device according to the present embodiment is short-circuited from the first and second variable composite current transformers 10 ₁ and 10 ₂ and the first variable composite current transformer 10 _1. current and the difference current between the short-circuit current which is input from the second variable synthesizing current transformer 10 ₂ (hereinafter. referred to as "short-circuit current I _Ry") when the transformer 5 for detecting the internal short-circuit fault on the basis of, transformer The _first to _third circuit breakers 2 ₁ to 2 ₃ installed in the R-phase, S-phase, and T-phase on the primary side of the transformer 5 and the R-phase, S-phase, and T-phase on the secondary side of the transformer 5 respectively. And a current differential relay 20 that collectively cuts off the _fourth to _sixth circuit breakers 2 ₄ to 2 ₆ respectively installed in the circuit board.

Here, the first variable composite current transformer 10 ₁ includes _first to _third current transformers 3 ₁ to ₃ 3 installed in the R-phase, S-phase, and T-phase on the primary side of the transformer 5, respectively. For synthesizing the current input from the current ratio of -0.5: 0.5: -1.5. Thus, the first from the variable synthetic current transformer 10 _1, the current flowing inverted and 0.5 times the current and S phase of the polarity of the current flowing through the primary side of the R-phase transformer 5 0. A sum current of the current multiplied by 5 and the current multiplied by 1.5 by inverting the polarity of the current flowing through the T phase is output.
Similarly, the second variable composite current transformer 10 ₂ includes _fourth to _sixth current transformers 3 _{4 to} 3 ₆ installed in the R-phase, S-phase, and T-phase on the secondary side of the transformer 5, respectively. For synthesizing the current input from the current ratio of -0.5: 0.5: -1.5. Thus, the second is a variable synthesizing current transformer 10 _2, the current flowing through the current and the S-phase polarity and 0.5 times by inverting the current flowing through the secondary side of the R-phase transformer 5 0. A sum current of the current multiplied by 5 and the current multiplied by 1.5 by inverting the polarity of the current flowing through the T phase is output.
Further, the second variable composite current transformer 10 ₂ has a polarity of the short-circuit current input from the second variable composite current transformer 10 ₂ to the current differential relay 20 from the first variable composite current transformer 10 _1. It is connected to the current differential relay 20 so that the polarity of the short circuit current input to the current differential relay 20 is reversed.

Therefore, the primary load currents flowing in the R-phase, S-phase, and T-phase on the primary side (transmission end) of the transformer 5 when no short circuit accident has occurred are represented by I _1R , I _1R , I _1T , R-phase secondary side of the vessel 5 (receiving end), S phase and the secondary load current flowing to the T-phase I _2R, I _2S, expressed in I _2T, the first variable combining current from current transformer 10 ₁ primary load current i ₁ which is input to the differential relay 20, as in the case of the overcurrent relay 4 according to the first embodiment described above, the polarity is the primary load current I _1R negative R phase 0 .5 times the current (= −0.5I _1R ), the S phase primary load current I _1S multiplied by 0.5 (= 0.5I _1S ), and the negative polarity T phase primary load current I The vector sum of the current obtained by multiplying _1T by 1.5 (= −1.5I _1T ), but the R-phase primary load current I _1R , the S-phase primary load current I _1S and the T-phase primary load Electric Since the phase and I _1T are displaced at 120 ° intervals (see FIG. 2 (a)), 1 of the primary load current amplitude i ₁ is R phase of the primary load current I _1R (S-phase and T-phase primary 3 ^1/2 times the amplitude of the load currents I _1S and I _1T ).
i ₁ = −0.5I _1R + 0.5I _1S −1.5I _1T
| I ₁ | = | −0.5I _1R + 0.5I _1S −1.5I _1T |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _1R |
= 3 ^1/2 × | I _1R | (= 3 ^1/2 × | I _1S | = 3 ^1/2 × | I _1T |)
Similarly, the secondary load current i ₂ input from the second variable composite current transformer 10 ₂ to the current differential relay 20 is a current obtained by multiplying the R-phase secondary load current I _2R having a negative polarity by 0.5. (= −0.5I _2R ), the current obtained by multiplying the S-phase secondary load current I _2S by 0.5 (= 0.5I _2S ) and the negative polarity T-phase secondary load current I _2T of 1.5 It becomes a vector sum (polarity is negative) with the multiplied current (= −1.5I _2T ), and the amplitude of the secondary load current i ₂ is the R-phase secondary load current I _2R (the S-phase and T-phase secondary loads). It becomes 3 ^1/2 times the amplitude of the currents I _2S and I _2T ).
_{i 2 = - (- 0.5I 2R} + 0.5I 2S -1.5I 2T)
| I ₂ | = | −0.5I _2R + 0.5I _2S −1.5I _2T |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _2R |
= 3 ^1/2 × | I _2R | (= 3 ^1/2 × | I _2S | = 3 ^1/2 × | I _2T |)
As a result, the load current I input to the current differential relay 20 is represented by a vector sum of the primary load current i ₁ and the secondary load current i _2, and the amplitude of the load current I is “0” (| I | = | I ₁ + i ₂ | = 0).

Further, for example, when a short circuit accident occurs on the primary side inside the transformer 5, short circuit currents flowing in the R phase, S phase, and T phase of the primary transmission and distribution line of the transformer 5 are represented by I _FR , I _FS , In terms of I _FT , the short-circuit current I _Ry (the difference between the short-circuit current input from the first variable composite current transformer 10 ₁ and the short-circuit current input from the second variable composite current transformer 10 ₂ ) is In the same manner as in the case of the overcurrent relay 4 according to the first embodiment described above, it is expressed as follows according to the accident aspect.
(1) In case of short-circuit accident between R phase and S phase (see Fig. 3 (a))
I _Ry = 0.5 (I _FS -I _FR )
| I _Ry | = | 0.5 (I _FS −I _FR ) | = | I _FS | (= | I _FR |)
(2) In the case of a short circuit accident between the S phase and the T phase (see FIG. 3B)
I _Ry = 0.5I _FS -1.5I _FT
| I _Ry | = | 0.5 I _FS −1.5 I _FT | = 2 × | I _FS | (= 2 × | I _FT |)
(3) In the case of a short circuit accident between T phase and R phase (see Fig. 4 (a))
I _Ry = − (0.5I _FR + 1.5I _FT )
| I _Ry | = | 0.5 I _FR +1.5 I _FT | = | I _FR | (= | I _FT |)
(4) In the case of a short circuit accident between R phase, S phase, and T phase (see FIG. 4B)
I _Ry = −0.5 I _FR + I _FS −1.5 I _FT
| I _Ry | = | −0.5 I _FR +0.5 I _FS −1.5 I _FT |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _FR |
= 3 ^1/2 × | I _FR | (= 3 ^1/2 × | I _FS | = 3 ^1/2 × | I _FT |)

Current differential relay 20, when the amplitude of the short-circuit current I _Ry exceeds the current setting value, it is determined that the short-circuit failure occurs inside the transformer 5, the circuit breaker 2 ₁ of the first to sixth Block ₆ and ₆ together.

In the first variable composite current transformer 10 ₁ , the composite current ratio of the currents input from the _first to _third current transformers 3 _{1 to} 3 ₃ is set to “−0.5: 0.5: −1. 5 ”, but“ −0.5: −1.5: 0.5 ”,“ 0.5: −0.5: −1.5 ”,“ 0.5: −1.5: −0 ” .5 "," -1.5: 0.5: -0.5 "or" -1.5: -0.5: 0.5 ".
The same applies to the second variable composite current transformer 10 ₂ .

Next, a protective relay device according to a third embodiment of the present invention will be described with reference to FIG.
The protection relay device according to the present embodiment is a power reception protection relay device for protecting the first and second transmission / distribution lines 1L and 2L from a short circuit accident in the premises. As shown in FIG. Second variable composite current transformer 10 ₁ , 10 ₂ , short-circuit current input from _first variable composite current transformer 10 _1, and short-circuit current input from second variable composite current transformer 10 ₂ When a short-circuit accident is detected on the premises based on the sum current (hereinafter referred to as “short-circuit current I _Ry ”), the first installed in the R-phase, S-phase, and T-phase of the first transmission and distribution line 1L, respectively. Or the third to third circuit breakers 2 ₁ to 2 ₃ and the _fourth to _sixth circuit breakers 2 ₄ to 2 ₆ respectively installed in the R phase, S phase and T phase of the second transmission and distribution line 2L. And an overcurrent relay 30.

Here, the first variable composite current transformer 10 ₁ includes _first to _third current transformers 3 ₁ to ₃ 3 installed in the R phase, S phase, and T phase of the first power transmission and distribution line 1L, respectively. For synthesizing the currents input at a combined current ratio of −0.5: 0.5: −1.5. Thus, the first from the variable synthetic current transformer 10 _1, the current flowing through the first transmission and distribution 0.5 times by reversing the polarity of the current through the R phase of the electric wire 1L the current and S phase 0. The sum of the current multiplied by 5 and the current multiplied by 1.5 by inverting the polarity of the current flowing through the T phase is output.
Similarly, the second variable composite current transformer 10 ₂ includes _fourth to _sixth current transformers 3 _{4 to} 3 ₆ installed in the R phase, the S phase, and the T phase of the second transmission and distribution line 2L, respectively. For synthesizing the currents input at a combined current ratio of −0.5: 0.5: −1.5. Thus, from the second variable synthesizing current transformer 10 _2, the current flowing through the second 0.5 times by inverting the polarity of the current flowing through the R-phase of the transmission and distribution lines 2L of the current and the S-phase zero. The sum of the current multiplied by 5 and the current multiplied by 1.5 by inverting the polarity of the current flowing through the T phase is output.

Therefore, the load current I input from the first and second variable composite current transformers 10 ₁ and 10 ₂ to the overcurrent relay 30 when no short circuit accident occurs on the premises is the same as that of the first embodiment described above. In the same manner as in the case of the overcurrent relay 4 by the above, the current (= −0.5I _R ) obtained by multiplying the negative polarity R-phase load current I _R by 0.5 and the S-phase load current I _S by 0.5 The vector sum of the multiplied current (= 0.5 I _S ) and the current (= −1.5 I _T ) obtained by multiplying the negative polarity T-phase load current I _T by 1.5, and the amplitude of the load current I is R It becomes 3 ^1/2 times the amplitude of the phase load current I _R (S-phase and T-phase load currents I _S , I _T ) (see FIG. 2A).
I = −0.5I _R + 0.5I _S −1.5I _T
| I | = | −0.5I _R + 0.5I _S −1.5I _T |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _R |
= 3 ^1/2 × | I _R | (= 3 ^1/2 × | I _S | = 3 ^1/2 × | I _T |)

In addition, when a short-circuit accident occurs on the premises, the short-circuit currents flowing in the R-phase, S-phase, and T-phase of the first and second power transmission lines 1L, 2L are expressed as I _FR , I _FS , I _FT The current I _Ry (the sum of the short-circuit current input from the first variable composite current transformer 10 ₁ and the short-circuit current input from the second variable composite current transformer 10 ₂ ) is the first implementation described above. Similar to the case of the overcurrent relay 4 according to the example, it is expressed as follows according to the accident aspect.
(1) In case of short-circuit accident between R phase and S phase (see Fig. 3 (a))
I _Ry = 0.5 (I _FS -I _FR )
| I _Ry | = | 0.5 (I _FS −I _FR ) | = | I _FS | (= | I _FR |)
(2) In the case of a short circuit accident between the S phase and the T phase (see FIG. 3B)
I _Ry = 0.5I _FS -1.5I _FT
| I _Ry | = | 0.5 I _FS −1.5 I _FT | = 2 × | I _FS | (= 2 × | I _FT |)
(3) In the case of a short circuit accident between T phase and R phase (see Fig. 4 (a))
I _Ry = − (0.5I _FR + 1.5I _FT )
| I _Ry | = | 0.5 I _FR +1.5 I _FT | = | I _FR | (= | I _FT |)
(4) In the case of a short circuit accident between R phase, S phase, and T phase (see FIG. 4B)
I _Ry = −0.5 I _FR + I _FS −1.5 I _FT
| I _Ry | = | −0.5 I _FR +0.5 I _FS −1.5 I _FT |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _FR |
= 3 ^1/2 × | I _FR | (= 3 ^1/2 × | I _FS | = 3 ^1/2 × | I _FT |)

When the amplitude of the short-circuit current _IRy exceeds the current set value, the overcurrent relay 30 determines that a short-circuit accident has occurred in the premises and collects the _first to _sixth circuit breakers 2 ₁ to 2 ₆ at _once. Cut off.

In the first variable composite current transformer 10 ₁ , the composite current ratio of the currents input from the _first to _third current transformers 3 _{1 to} 3 ₃ is set to “−0.5: 0.5: −1. 5 ”, but“ −0.5: −1.5: 0.5 ”,“ 0.5: −0.5: −1.5 ”,“ 0.5: −1.5: −0 ” .5 "," -1.5: 0.5: -0.5 "or" -1.5: -0.5: 0.5 ".
The same applies to the second variable composite current transformer 10 ₂ .

Next, a protective relay device according to a fourth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 11, the protective relay device according to the present embodiment includes the first and second variable composite current transformers 10 ₁ and 10 ₂ and the short-circuit current from the _first variable composite current transformer 10 _1. When a short-circuit fault in the transmission / distribution line is detected based on a difference current (hereinafter referred to as “short-circuit current I _Ry ”) from the short-circuit current from the second variable composite current transformer 10 _{2, 1st} to _3rd circuit breakers 2 ₁ to 2 ₃ installed in R phase, S phase and T phase of distribution line and R phase, S phase and T phase of power transmission and distribution line on receiving end bus side, respectively First and second pulse code modulation current differential relays 60 ₁ and 60 ₂ (hereinafter referred to as “first and second PCMs”) that collectively cut off the _fourth to _sixth circuit breakers 2 ₄ to 2 ₆ respectively. Current differential relays 60 ₁ , 60 ₂ ”).
Note that the first and second PCM current differential relays 60 ₁ and 60 ₂ transmit and receive a short-circuit current via a communication network.

Here, the first variable combining current transformer 10 _1, first to third current transformer 3 ₁ to 3 in which R-phase transmission and distribution lines of a power supply terminal bus side, the S-phase and T-phase are respectively installed _This is for synthesizing the current input from ₃ at a combined current ratio of −0.5: 0.5: −1.5. As a result, the first variable composite current transformer 10 ₁ reverses the polarity of the current flowing through the R phase of the power transmission / distribution line on the power supply end bus side and reverses the current multiplied by 0.5 and the current flowing through the S phase to 0. The sum of the current multiplied by 5 and the current multiplied by 1.5 by inverting the polarity of the current flowing through the T phase is output.
Similarly, the second variable composite current transformer 10 ₂ includes _fourth to sixth current transformers 3 ₄ to 3 installed in the R-phase, S-phase, and T-phase of the power transmission and distribution line on the power receiving end bus side, respectively. ₆ for synthesizing the current input from ₆ at a combined current ratio of −0.5: 0.5: −1.5. As a result, the second variable composite current transformer 10 ₂ reduces the polarity of the current flowing through the R phase of the power transmission / distribution line on the power receiving end bus side by 0.5 and the current flowing through the S phase to 0. The sum of the current multiplied by 5 and the current multiplied by 1.5 by inverting the polarity of the current flowing through the T phase is output.
Further, the second variable composite current transformer 10 ₂ has the polarity of the short-circuit current input from the second variable composite current transformer 10 ₂ to the second PCM current differential relay 60 ₂ in the first variable composite current transformer. from Nagareki 10 ₁ so as to be opposite to the polarity of the first PCM current short-circuit current which is input to the differential relay 60 ₁ is connected to a second PCM current differential relay 60 _2.

Therefore, the transmission end load current flowing in the R phase, S phase and T phase of the transmission end of the transmission / distribution line when no short circuit accident has occurred in the transmission / distribution line is expressed as I _aR , I _aS , I _aT , R-phase receiving end of the electric wire, S-phase and the receiving end load current flowing to the T-phase I _bR, I _bS, expressed in I _bT, first PCM current differential from the first variable combining current transformer 10 ₁ sending end load current I _a that is input to the relay 60 _1, in the same manner as in the first overcurrent relay 4 in accordance with embodiments of the above, the polarity is the sending end load current I _aR negative R phase 0. Five times the current (= −0.5 I _aR ), 0.5 times the S-phase transmission end load current I _aS (= 0.5 I _aS ) and the negative polarity T-phase transmission end load current I _aT Is the vector sum of the current multiplied by 1.5 (= −1.5 I _aT ), but the R-phase transmission end load current I _aR and the S-phase transmission end load current Since the current I _aS and the T-phase transmission end load current I _aT are shifted in phase by 120 ° (see FIG. 2A), the amplitude of the transmission end load current I _a is R-phase transmission end load current. It becomes 3 ^1/2 times the amplitude of I _aR (S-phase and T-phase transmission end load currents I _aS , I _aT ).
I _a = −0.5 I _aR +0.5 I _aS −1.5 I _aT
| I _a | = | −0.5 I _aR +0.5 I _aS −1.5 I _aT |
= {(3 ^1/2 ) ² /2+1.5 ² } ^1/2 × | I _aR |
= 3 ^1/2 × | I _aR | (= 3 ^1/2 × | I _aS | = 3 ^1/2 × | I _aT |)
Similarly, the receiving end load current I _b inputted from the second variable composite current transformer 10 ₂ to the second PCM current differential relay 60 ₂ is the R phase receiving end load current I _bR having a negative polarity. 0.5 times the current (= -0.5 I _bR ), 0.5 times the S-phase receiving end load current I _bS (= 0.5 I _bS ) and the negative polarity T-phase receiving end load current Vector sum (polarity is negative) with a current (= −1.5I _bT ) _obtained by multiplying I _bT by 1.5, and the amplitude of the receiving end load current I _b is the R receiving end load current I _bR (S phase and It becomes 3 ^1/2 times the amplitude of the T-phase receiving end load currents I _bS , I _bT ).
I _b = − (− 0.5 I _bR +0.5 I _bS −1.5 I _bT )
| I _b | = | −0.5 I _bR +0.5 I _bS −1.5 I _bT |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _bR |
= 3 ^1/2 × | I _bR | (= 3 ^1/2 × | I _bS | = 3 ^1/2 × | I _bT |)
As a result, the load current I input to the first and second PCM current differential relays 60 ₁ and 60 ₂ is expressed as a vector sum of the transmission end load current I _a and the reception end load current I _b, and the load The amplitude of the current I is “0” (| I | = | I _a + I _b | = 0).

Moreover, when the short-circuit current that flows in the R-phase, S-phase, and T-phase of the transmission / distribution line is expressed by I _FR , I _FS , I _FT when a short-circuit accident occurs in the transmission / distribution line, the short-circuit current I _Ry (first variable synthesis short-circuit current from the current transformer 10 ₁ and a difference current between the second short-circuit current from the variable synthetic current transformer 10 _2), in the same manner as in the first overcurrent relay 4 it is according to an embodiment of the above According to the accident aspect, it is expressed as follows.
(1) In case of short-circuit accident between R phase and S phase (see Fig. 3 (a))
I _Ry = 0.5 (I _FS -I _FR )
| I _Ry | = | 0.5 (I _FS −I _FR ) | = | I _FS | (= | I _FR |)
(2) In the case of a short circuit accident between the S phase and the T phase (see FIG. 3B)
I _Ry = 0.5I _FS -1.5I _FT
| I _Ry | = | 0.5 I _FS −1.5 I _FT | = 2 × | I _FS | (= 2 × | I _FT |)
(3) In the case of a short circuit accident between T phase and R phase (see Fig. 4 (a))
I _Ry = − (0.5I _FR + 1.5I _FT )
| I _Ry | = | 0.5 I _FR +1.5 I _FT | = | I _FR | (= | I _FT |)
(4) In the case of a short circuit accident between R phase, S phase, and T phase (see FIG. 4B)
I _Ry = −0.5 I _FR + I _FS −1.5 I _FT
| I _Ry | = | −0.5 I _FR +0.5 I _FS −1.5 I _FT |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _FR |
= 3 ^1/2 × | I _FR | (= 3 ^1/2 × | I _FS | = 3 ^1/2 × | I _FT |)

The first and second PCM current differential relays 60 ₁ and 60 ₂ determine that a short-circuit accident has occurred in the transmission and distribution line when the amplitude of the short-circuit current I _Ry exceeds the current settling value. The 1st to 6th circuit breakers 2 ₁ to 2 ₆ are collectively cut off.

In the first variable composite current transformer 10 ₁ , the composite current ratio of the currents input from the _first to _third current transformers 3 _{1 to} 3 ₃ is set to “−0.5: 0.5: −1. 5 ”, but“ −0.5: −1.5: 0.5 ”,“ 0.5: −0.5: −1.5 ”,“ 0.5: −1.5: −0 ” .5 "," -1.5: 0.5: -0.5 "or" -1.5: -0.5: 0.5 ".
The same applies to the second variable composite current transformer 10 ₂ .

As described above, in the first to fourth embodiments, by using a variable composite current transformer (such as the variable composite current transformer 10 shown in FIG. 1), a current transformer and a short circuit protection relay (FIG. 1) are used. The number of installed overcurrent relays 4) can be further reduced. However, as described above, the amplitude of the load current I is ^31/2 times and a short circuit in a short circuit accident between the S phase and the T phase. the amplitude of current I _Ry is twice the amplitude of the short-circuit current I _Ry in short circuit of the short-circuit fault and T-phase -R phase of R-phase -S phase, also in the short circuit of the R-phase -S phase -T phase short circuit the amplitude of the current I _Ry is 3 ^1/2 times the amplitude of the short-circuit current I _Ry in short circuit of the short-circuit fault and T-phase -R phase of R-phase -S phase. Therefore, the detection sensitivity and operating time of the short circuit protection relay cannot be made the same for all accident aspects.

Therefore, the accident aspect is determined by using any one of the following first to fifth accident aspect determination methods, and the short-circuit current from the variable composite current transformer is multiplied by 1 or 1/2 according to the accident aspect determination result. An arithmetic processing unit that doubles or 1/3 ^1/2 may be provided between the variable composite current transformer and the short circuit protection relay or in the short circuit protection relay.

(First accident mode judgment method)
The accident aspect is determined based on the three line voltages, the three phase voltages, or the phase / line voltage (combination of the phase voltage and the line voltage).

Table 1 shows the accident condition determination conditions based on the three line voltages. In addition, ○ mark indicates the line voltage in which the voltage drop is detected based on the voltage information from the undervoltage relay installed on the bus, and the X mark is based on the voltage information from this undervoltage relay. The line voltage in which no voltage drop was detected is shown (the voltage drop detection sensitivity is about 75 to 80% of the rated voltage).

Table 2 shows the accident condition determination conditions based on the three phase voltages. In addition, a circle indicates a phase voltage in which a voltage drop is detected based on voltage information from an undervoltage relay installed on the bus, and a cross indicates a voltage based on voltage information from the undervoltage relay. The phase voltage in which no decrease was detected is indicated (the voltage drop detection sensitivity is about 75 to 80% of the rated voltage).

Table 3 shows the accident condition judgment conditions based on the phase / line voltage. The circles indicate the phase voltage and line voltage at which a voltage drop is detected based on the voltage information from the undervoltage relay installed on the bus, and the x indicates voltage information from the undervoltage relay. The phase voltage and the line voltage in which no voltage drop was detected based on the above are shown (voltage drop detection sensitivity is about 75 to 80% of the rated voltage).

(Second accident mode judgment method)
The accident aspect is determined based on the voltage value and phase of one line voltage and one phase voltage.

For example, based on the fact that the phase of the line voltage V _TR between the T phase and the R phase is 210 ° and the phase of the phase voltage V _R of the _R phase is 0 ° (see FIG. 2B), the transmission and distribution lines The R-phase-S phase line voltage V _RS at the time of the short-circuit accident between the R-phase and S-phase and the S-phase-T-phase line voltage V _ST at the time of the short-circuit accident between the S-phase and the T-phase 85V, it is determined that a short-circuit accident has occurred on the condition that the line voltage V _TR between the T phase and the R phase is equal to or lower than a predetermined first voltage value k1 = 85 V, and the line between the T phase and the R phase The voltage V _TR is equal to or lower than a predetermined second voltage value k2 = 104.3 V, and the phase of the line voltage V _TR between the T phase and the R phase before the short circuit accident is 210 ° as a reference. the T-phase -R phase of the phase of the line voltage V _TR is advanced or delayed by a predetermined angular range α (5.95 ° ≦ α ≦ 30 ° or -30 ° α ≦ -5.95 °) determining a short-circuit failure condition has occurred (the following (1-1) and (1-2) refer to formula).
V _TR ≦ [{(110/3 ^1/2 ) × 1.5} ² + (85/2) ² ] ^1/2
≦ (95.26 ² +42.5 ² ) ^1/2
≦ 104.3 (V) (1-1)
α ≧ 30 ° -tan ⁻¹ (42.5 / 95.26)
≧ 5.95 (°) (1-2)

Moreover, the accident aspect is determined as follows.
(1) In the case of a short-circuit accident between the R phase and the S phase The line voltage V _TR between the T phase and the R phase is 104.3 V or less, and the line voltage V _TR between the T phase and the R phase before the short circuit accident is When the phase of the line voltage V _TR between the T phase and the R phase is delayed by an angle range α (+ α) with respect to the phase = 210 ° as a reference, it is determined that the short-circuit accident occurs between the R phase and the S phase (FIG. 12 ( a)).
(2) In the case of a short circuit accident between the S phase and the T phase The line voltage V _TR between the T phase and the R phase is 104.3 V or less, and the line voltage V _TR between the T phase and the R phase before the short circuit accident is When the phase of the line voltage V _TR between the T phase and the R phase is advanced only within the angle range α (−α) with respect to the phase = 210 ° as a reference, it is determined that a short circuit accident between the S phase and the T phase occurs (FIG. (See (b)).
(3) In the case of a short circuit accident between the T phase and the R phase The line voltage V _TR between the T phase and the R phase is 85 V or less, and the phase of the line voltage V _TR between the T phase and the R phase before the short circuit accident = The phase of the line voltage V _TR between the T phase and the R phase is not delayed or advanced by an angle range α with respect to 210 ° (that is, greater than −5.95 ° and 5.95 °). And the phase of the R-phase phase voltage V _R before the short circuit accident is 0 ° as a reference, and the phase of the R-phase phase voltage V _R has a predetermined other angle range β (6.76 ° ≦ β ≦ 60 °, see (Equation 1-3)) (−β), it is determined that there is a short circuit accident between the T phase and the R phase (see FIG. 12C).
β ≧ 60 ° -tan ⁻¹ [42.5 / {110 / (2 × 3 ^1/2 )}]
≧ 6.76 (°) (1-3)
(4) In the case of a short circuit accident between R phase, S phase and T phase The line voltage V _TR between T phase and R phase is 85V or less, and the line voltage V _TR between T phase and R phase before the short circuit accident. The phase of the line voltage V _TR between the T-phase and the R-phase is not delayed or advanced by the angle range α with respect to the phase of 210 = 210 ° (that is, greater than −5.95 ° and 5 .. is smaller than .95 °), and the phase of the R phase voltage V _R before the short-circuit accident is 0 ° or the phase of the R phase voltage V _R is delayed or advanced by another angle range β. It is determined that a short-circuit accident between the R phase, the S phase, and the T phase is performed on the condition that the phase is not larger (that is, larger than −6.76 ° and smaller than 6.76 °) (FIG. 12D). reference).

Although the T-phase-R phase line voltage V _TR and the R-phase phase voltage V _R are used, any one of the voltage combinations indicated by circles in Table 4 may be used. However, it is necessary to change the short-circuit accident occurrence determination condition and the accident aspect determination condition described above according to the combination of voltages.

(Third accident mode determination method)
The accident aspect is determined based on the voltage value and phase of one line voltage and the phase of the short-circuit current _IRy .

For example, with reference to the phase of the T-phase to R-phase line voltage V _TR being 210 °, the R-phase to S-phase line voltage V _RS at the time of a short-circuit fault between the R-phase and S-phase of the transmission and distribution line and S phase -T When the line voltage V _ST between phases S phase -T phase when a short circuit accident and 85V of short-circuit failure detection sensitivity, a first voltage line voltage V _TR of the T-phase -R phase is given It is determined that a short-circuit accident has occurred on condition that the value k1 = 85 V or less, and the T-phase to R-phase line voltage V _TR is a predetermined second voltage value k2 = 104.3 V or less, and The phase of the line voltage V _TR between the T phase and the R phase before the short circuit accident = 210 ° as a reference, the phase of the line voltage V _TR between the T phase and the R phase at the time of the short circuit accident is delayed by a predetermined angle range α. A short-circuit accident occurs on the condition that it is moving or advanced (5.95 ° ≦ α ≦ 30 ° or −30 ° ≦ α ≦ −5.95 °) A constant ((1-1) see formula and (1-2) below).

Moreover, the accident aspect is determined as follows.
(1) In the case of a short-circuit accident between the R phase and the S phase The line voltage V _TR between the T phase and the R phase is 104.3 V or less, and the line voltage V _TR between the T phase and the R phase before the short circuit accident is When the phase of the line voltage V _TR between the T phase and the R phase is delayed by an angle range α (+ α) with respect to the phase = 210 ° as a reference, it is determined that the short-circuit accident occurs between the R phase and the S phase (FIG. 13 ( a)).
(2) In the case of a short circuit accident between the S phase and the T phase The line voltage V _TR between the T phase and the R phase is 104.3 V or less, and the line voltage V _TR between the T phase and the R phase before the short circuit accident is When the phase of the line voltage V _TR between the T phase and the R phase is advanced only within the angle range α (−α) with respect to the phase = 210 ° as a reference, it is determined that a short circuit accident between the S phase and the T phase occurs (FIG. 13). (See (b)).
(3) In the case of a short circuit accident between the T phase and the R phase The line voltage V _TR between the T phase and the R phase is 85 V or less, and the phase of the line voltage V _TR between the T phase and the R phase before the short circuit accident = The phase of the line voltage V _TR between the T phase and the R phase is not delayed or advanced by an angle range α with respect to 210 ° (that is, greater than −5.95 ° and 5.95 °). And the phase of the short-circuit current I _Ry is determined in consideration of arc resistance and the like with a predetermined first angle range γ (−150 ° ≦ γ ≦ −90 °, γ is an impedance angle θ = 75 °) If it is within the range, it is determined that there is a short circuit accident between the T phase and the R phase (see FIG. 13C).
(4) In the case of a short circuit accident between R phase, S phase and T phase The line voltage V _TR between T phase and R phase is 85V or less, and the line voltage V _TR between T phase and R phase before the short circuit accident. The phase of the line voltage V _TR between the T-phase and the R-phase is not delayed or advanced by the angle range α with respect to the phase of 210 = 210 ° (that is, greater than −5.95 ° and 5 Smaller than .95 °) and the phase of the short-circuit current I _Ry is within a predetermined second angle range δ (−90 ° ≦ δ ≦ −30 °, where δ is an impedance angle θ = 75 ° and arc resistance is taken into consideration. If it is within the range, it is determined that there is a short-circuit accident between the R phase, the S phase, and the T phase (see FIG. 13D).

(Fourth accident mode determination method)
Accident aspects determination transformer 110 shown in FIG. 14 (accident appearance determination transformer according to a first embodiment of the present invention) is placed to the bus, composite voltage output from the accident aspect determination transformer 110 V _{RS- Based on} the voltage value and phase of _2T and the phase of the short-circuit current I _Ry , the accident aspect is determined as follows.
Here, the secondary side of the accident phase determination transformer 110 sets the phase voltage V _R of the R phase in the polarity direction, the phase voltage V _S of the S phase in the opposite polarity direction, and the phase voltage V _T of the T phase in the opposite direction. The wires are wired so as to be doubled in the polarity direction. As a result, the composite voltage V _RS-2T output from the accident aspect determination transformer 110 is expressed by the following equation.
V _RS-2T = V _R -V _S -2V _T
Further, although the impedance angle θ is usually 75 °, the phase angle of the short-circuit current I _Ry takes into consideration the arc resistance, from 30 ° (−45 °) to 90 ° (+ 15 °) which is the maximum angle at the time of a short-circuit accident. ).

(1) In the case of a short-circuit accident between the R phase and the S phase The voltage value of the composite voltage V _RS-2T is a predetermined first composite voltage value K ₁ = 100.1 V or less (see equation (2-1)). In addition, the phase of the composite voltage V _RS-2T at the time of the short-circuit accident is set to a predetermined first composite voltage angle range ε ₁ (7 based on the fact that the phase of the composite voltage V _RS-2T at the normal time is 19.1 °. .10 ° (= X ₁ ) ≦ ε ₁ ≦ 40.9 ° (= X ₂ ) (Refer to equations (2-2) and (2-3)) (+ ε ₁ ) and short circuit When the phase of the current I _Ry is delayed (+ λ ₁ ) by a predetermined first short-circuit current angle range λ ₁ (160.9 ° ≦ λ ₁ ≦ 220.9 °) (+ λ ₁ ), a short circuit between the R phase and the S phase Judge as an accident.
K ₁ = [(83.15) ² + (72.01 × 85/110) ² ] ^1/2
= 100.1 (V) (2-1)
X ₁ = cos ⁻¹ (83.15 / 110.0) −cos ⁻¹ (83.15 / 110.05)
= 7.10 (°) (2-2)
X ₂ = 60-19.1
= 40.9 (°) (2-3)
(2) In the case of a short circuit accident between the S phase and the T phase The voltage value of the composite voltage V _RS-2T is a predetermined second composite voltage value K ₂ = 107.6 V or less (see the formula (2-4)), In addition, the phase of the composite voltage V _RS-2T at the time of the short-circuit accident is determined to be a predetermined second composite voltage angle range ε ₂ (4 based on the phase of the composite voltage V _RS-2T at the normal time being 19.1 °. .12 ° (= X ₃ ) ≦ ε ₂ ≦ 19.1 ° (= X ₄ ) (see formulas (2-5) and (2-6)) (−ε ₂ ) When the phase of the short-circuit current I _Ry is delayed (+ λ ₂ ) by a predetermined second short-circuit current angle range λ ₂ (100.9 ° ≦ λ ₂ ≦ 160.9 °) (between S phase and T phase) Judged as a short circuit accident.
K ₂ = [(103.94) ² + (36.01 × 85/110) ² ] ^1/2
= 107.6 (V) (2-4)
X ₃ = cos ⁻¹ (103.94 / 110) −cos ⁻¹ (103.94 / 107.60)
= 4.12 (°) (2-5)
X ₄ = 19.1-0
= 19.1 (°) (2-6)
(3) In the case of a short-circuit accident between the T phase and the R phase The voltage value of the composite voltage V _RS-2T is equal to or less than a predetermined third composite voltage value K ₃ = 86.0 V (see formula (2-7)) Further, the phase of the composite voltage V _RS-2T at the time of a short-circuit accident is determined to be a predetermined third composite voltage angle range ε ₃ (3 based on the phase of the composite voltage V _RS-2T at the normal time being 19.1 °. .09 ° (= X ₅ ) ≦ ε ₃ ≦ 79.1 ° (= X ₆ ) (see formulas (2-8) and (2-9)) (−ε ₃ ) When the phase of the short-circuit current I _Ry is delayed by (+ λ ₃ ) within a predetermined third short-circuit current angle range λ ₃ (40.9 ° ≦ λ ₃ ≦ 100.9 °), the phase between the T phase and the R phase Judged as a short circuit accident.
K ₃ = [(20.79) ² + (108.02 × 85/110) ² ] ^1/2
= 86.0 (V) (2-7)
^{_{X 5 = cos -1 (20.79 /}} 110) -cos -1 (20.79 / 86.02)
= 3.09 (°) (2-8)
X ₆ = 60 + 19.1
= 79.1 (°) (2-9)
(4) In the case of a short-circuit accident between the R phase, the S phase, and the T phase The voltage value of the composite voltage V _RS-2T is equal to or less than a predetermined fourth composite voltage value K ₄ = 85 V (75 to 80% of the rated voltage). The phase of the composite voltage V _RS-2T at the time of the short-circuit accident is a predetermined fourth composite voltage angle range ε ₄ (wherein the phase of the composite voltage V _RS-2T at the normal time is 19.1 °. −3.09 ° (= −X ₅ ) ≦ ε ₄ ≦ 7.10 ° (= X ₁ )) (that is, the same phase), and the phase of the short-circuit current I _Ry is predetermined. If it is delayed (+ λ ₄ ) within the fourth short-circuit current angle range λ ₄ (100.9 ° ≦ λ ₄ ≦ 160.9 °), it is determined as a short-circuit accident between the R phase, the S phase, and the T phase.

(Fifth accident mode determination method)
The accident appearance judging transformer 120 (accident appearance judging transformer according to the second embodiment of the present invention) shown in FIG. 15 is installed on the bus, and the composite voltage V _R− output from the accident appearance judging transformer 120 is provided. _{Based on} the voltage value and phase of _{S + 2T} and the phase of the short-circuit current I _Ry , the accident aspect is determined as follows.
Here, the secondary side of the accident phase determination transformer 120 has the R-phase voltage V _R in the polarity direction, the S-phase phase voltage V _S in the opposite polarity direction, and the T-phase phase voltage V _T in the polarity direction. They are wired so as to be doubled in the direction of synthesis. As a result, the composite voltage V _{R−S + 2T} output from the accident aspect determination transformer 120 is expressed by the following equation.
V _{R−S + 2T} = V _R −V _S + 2V _T
Further, although the impedance angle θ is usually 75 °, the phase angle of the short-circuit current I _Ry takes into consideration the arc resistance, from 30 ° (−45 °) to 90 ° (+ 15 °) which is the maximum angle at the time of a short-circuit accident. ).

(1) In the case of a short-circuit accident between the R phase and the S phase The voltage value of the composite voltage V _{R-S + 2T} is equal to or less than a predetermined fifth composite voltage value K ₅ = 100.1 V (see equation (3-1)) ), And the phase of the composite voltage V _{R-S + 2T} at the normal time is 280.9 °, and the phase of the composite voltage V _{R-S + 2T} at the time of the short-circuit accident is a predetermined fifth composite voltage The angle range ε ₅ (7.10 ° (= X ₇ ) ≦ ε ₅ ≦ 40.9 ° (= X ₈ ), see (3-2) and (3-3))) (− ε ₅ ), and the phase of the short-circuit current I _Ry is advanced only within a predetermined fifth short-circuit current angle range λ ₅ (40.9 ° ≦ λ ₅ ≦ 100.9 °) (−λ ₅ ). It is determined that there is a short circuit accident between the R phase and the S phase.
K ₅ = [(83.15) ² + (72.01 × 85/110) ² ] ^1/2
= 100.1 (V) (3-1)
^{_{X 7 = cos -1 (83.15 /}} 110.0) -cos -1 (83.15 / 110.05)
= 7.10 (°) (3-2)
X ₈ = 280.9-240
= 40.9 (°) (3-3)
(2) In the case of a short circuit accident between the S phase and the T phase The voltage value of the composite voltage V _{R-S + 2T} is equal to or less than a predetermined sixth composite voltage value K ₆ = 86.0 V (see formula (3-4)) ), And the phase of the composite voltage V _{R-S + 2T} at the normal time is 280.9 ° as a reference, the phase of the composite voltage V _{R-S + 2T} at the time of the short-circuit accident is a predetermined sixth composite voltage Angular range ε ₆ (3.09 ° (= X ₉ ) ≦ ε ₆ ≦ 79.1 ° (= X ₁₀ ) (see equations (3-5) and (3-6))) (+ ε ₆ ) and the phase of the short-circuit current I _Ry is advanced only within a predetermined sixth short-circuit current angle range λ ₆ (100.9 ° ≦ λ ₆ ≦ 160.9 °) (−λ ₆ ), It is determined that there is a short circuit accident between the S phase and the T phase.
K ₆ = [(20.79) ² + (108.02 × 85/110) ² ] ^1/2
= 86.0 (V) (3-4)
X ₉ = cos ⁻¹ (20.79 / 110) −cos ⁻¹ (20.79 / 86.02)
= 3.09 (°) (3-5)
X ₁₀ = 360-280.9
= 79.1 (°) (3-6)
(3) In the case of a short-circuit accident between the T phase and the R phase The voltage value of the composite voltage V _{R-S + 2T} is a predetermined seventh composite voltage value K ₇ = 107.6 V or less (see equation (3-7)) ), And the phase of the composite voltage V _{R-S + 2T} at the normal time is 280.9 ° as a reference, the phase of the composite voltage V _{R-S + 2T} at the time of the short-circuit accident is a predetermined seventh composite voltage Angular range ε ₇ (4.12 ° (= X ₁₁ ) ≦ ε ₇ ≦ 19.1 ° (= X ₁₂ ) (see equations (3-8) and (3-9)) (+ ε ₇ ) and the phase of the short-circuit current I _Ry is advanced only within a predetermined seventh short-circuit current angle range λ ₇ (160.9 ° ≦ λ ₇ ≦ 220.9 °) (−λ ₇ ), Judged as a short circuit accident between T phase and R phase.
K ₇ = [103.94 ² + (36.01 × 85/110) ² ] ^1/2
= 107.6 (V) (3-7)
^{_{X 11 = cos -1 (103.94 /}} 110) -cos -1 (103.94 / 107.60)
= 4.12 (°) (3-8)
X ₁₂ = 300-280.9
= 19.1 (°) (3-9)
(4) In the case of a short-circuit accident between the R phase, the S phase, and the T phase, the voltage value of the composite voltage V _{R-S + 2T} is a predetermined eighth composite voltage value K ₈ = 85 V (75 to 80% of the rated voltage) or less And the phase of the composite voltage V _{R-S + 2T} at the time of a short-circuit accident is a predetermined eighth composite on the basis that the phase of the composite voltage V _{R-S + 2T} at a normal time is 280.9 ° It is within the voltage angle range ε ₈ (−7.10 ° (= −X ₇ ) ≦ ε ₈ ≦ 3.09 ° (= X ₉ )) (that is, in phase), and the short circuit current I _When the phase of _Ry advances only within the predetermined eighth short-circuit current angle range λ ₈ (100.9 ° ≦ λ ₈ ≦ 160.9 °) (−λ ₈ ), between R phase, S phase, and T phase Judged as a short circuit accident.

The arithmetic processing unit multiplies the short-circuit current when the accident mode determination result indicates a short-circuit accident between the R phase and the S-phase or a short-circuit accident between the T phase and the R phase, and the accident mode determination result is the S phase- The short-circuit current is halved to indicate a short-circuit accident between the T phases, and the short-circuit current is set to 1 when the accident mode determination result indicates a short-circuit accident between the R phase, the S phase, and the T phase. / 3 ^1/2 times. Further, the arithmetic processing unit sets the load current I to 1/3 ^1/2 times.

As shown in FIG. 16, the arithmetic processing unit includes an accident aspect determination circuit 71 that determines an accident aspect using any one of the first to fifth accident aspect determination methods described above, and a short circuit from the variable composite current transformer. 1 and the first amplitude adjustment circuit 72 ₁ for multiplying the current, half a second amplitude adjusting circuit 72 ₂ for multiplying a short-circuit current, the load current I and the short circuit current 1/3 ^1/2 multiplying third the amplitude adjustment circuit 72 _3, either on the basis in accordance with a switch control signal S _SW input from accidents aspect determination circuit 71 of the first to third amplitude adjusting circuit 72 ₁ to 72 ₃ of the output signal 1 You may comprise with the selection switch 73 which selects one.

The selection switch 73 normally selects the output signal of the _third amplitude adjustment circuit 723. Thus, when the short circuit does not occur, the load current I from the variable synthetic current transformer, the after being 1/3 ^1/2 In the third amplitude adjusting circuit 72 _3, via a selection switch 73 Input to the short-circuit protection relay.

If the accident aspect determination circuit 71 determines that “a short-circuit accident between the S phase and the T phase”, it outputs a switch control signal _SSW that causes the selection switch 73 to select the output signal of the _second amplitude adjustment circuit 722. Thus, when the short circuit of the S-phase -T phase occurs, the short-circuit current from the variable synthetic current transformer, the after being half in the second amplitude adjusting circuit 72 _2, via selection switch 73 Input to the short-circuit protection relay.

In addition, when the accident aspect determination circuit 71 determines that “it is a short circuit accident between the R phase and the S phase” or “a short circuit accident between the T phase and the R phase”, the output signal of the _first amplitude adjustment circuit 721 is output. A switch control signal _SSW to be selected by the selection switch 73 is output. Thereby, when a short circuit accident between the R phase and the S phase or a short circuit accident between the T phase and the R phase occurs, the short circuit current from the variable composite current transformer is multiplied by ₁ in the first amplitude adjustment circuit 72 ₁ . Then, it is input to the short circuit protection relay via the selection switch 73.

Further, when the accident aspect determination circuit 71 determines that “a short-circuit accident between the R phase, the S phase, and the T phase”, the switch control signal S that causes the selection switch 73 to select the output signal of the _third width adjustment circuit 723. Outputs _SW . Thus, when a short circuit accident R phase -S phase -T phase occurs, the short-circuit current from the variable synthetic current transformer was 1/3 ^1/2 In the third amplitude adjusting circuit 72 ₃ Later, the signal is input to the short-circuit protection relay via the selection switch 73.

  As a result, the amplitude of the short-circuit current can be made the same regardless of the accident aspect, so that the detection sensitivity and the operation time of the short-circuit protection relay can be made the same.

Next, a fifth embodiment of the protective relay device of the present invention will be described with reference to FIG. 17 and FIG.
As shown in FIG. 17, the protective relay device according to the present embodiment includes a variable composite current transformer 10, a short-circuit current I _Ry input from the variable composite current transformer 10, and an instrument transformer 6 installed on the bus. When a short circuit accident of the transmission / distribution line is detected based on the voltage information (phase voltages V _R , V _S , V _T ) input from, the first installed in the R phase, S phase and T phase of the transmission / distribution line respectively. And an overcurrent relay with voltage suppression 50 that collectively cuts off the _first to _third circuit breakers 2 ₁ to 2 ₃ .

Here, the variable composite current transformer 10 combines the currents input from the _first to _third current transformers 3 ₁ to ₃ 3 installed in the R-phase, S-phase, and R-phase of the transmission and distribution lines, respectively. For synthesis at a ratio of -0.5: 0.5: -1.5. As a result, the variable composite current transformer 10 reverses the polarity of the current flowing through the R phase of the power transmission and distribution line by 0.5 times, and the current flowing through the S phase by 0.5 times and the T phase. The sum of the current and the current multiplied by 1.5 is output by inverting the polarity of the flowing current.

Therefore, the load current I input from the variable composite current transformer 10 to the overcurrent relay 50 with voltage suppression when no short circuit accident has occurred is the same as in the overcurrent relay 4 according to the first embodiment described above. Thus, a current obtained by multiplying the negative polarity R-phase load current I _R by 0.5 (= −0.5I _R ) and a current obtained by multiplying the S-phase load current I _S by 0.5 (= 0.5I _S). ) And a current obtained by multiplying the negative polarity T-phase load current I _T by 1.5 (= −1.5I _T ), and the amplitude of the load current I is the R-phase load current I _R (S-phase). And the amplitude of the T-phase load currents I _S and I _T ) is 3 ^1/2 times the amplitude (see FIG. 2A).
I = −0.5I _R + 0.5I _S −1.5I _T
| I | = | −0.5I _R + 0.5I _S −1.5I _T |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _R |
= 3 ^1/2 × | I _R | (= 3 ^1/2 × | I _S | = 3 ^1/2 × | I _T |)
Thus, the amplitude of the load current I is 3 ^1/2 times the amplitude of the R-phase load current I _R ((S-phase and T-phase load currents I _S , I _T ). The relay 50 calculates the corrected load current I ′ by multiplying the load current I by 1/3 ^{1/2 as} shown by the following equation.
I ′ = I × 1/3 ^1/2 = (− 0.5 I _R +0.5 I _S −1.5 I _T ) × 1/3 ^1/2
| I ′ | = | −0.5I _R + 0.5I _S −1.5I _T | × 1/3 ^1/2
= | I _R | (= | I _S | = | I _T |)

Moreover, when the short-circuit currents flowing in the R-phase, S-phase, and T-phase of the transmission and distribution line when a short-circuit accident occurs are represented by I _FR , I _FS , and I _FT , the short-circuit current I _Ry is the first implementation described above. As in the case of the overcurrent relay 4 according to the example, it is expressed as follows according to the accident aspect.
(1) In case of short-circuit accident between R phase and S phase (see Fig. 3 (a))
I _Ry = 0.5 (I _FS -I _FR )
| I _Ry | = | 0.5 (I _FS −I _FR ) | = | I _FS | (= | I _FR |)
(2) In the case of a short circuit accident between the S phase and the T phase (see FIG. 3B)
I _Ry = 0.5I _FS -1.5I _FT
| I _Ry | = | 0.5 I _FS −1.5 I _FT | = 2 × | I _FS | (= 2 × | I _FT |)
(3) In the case of a short circuit accident between T phase and R phase (see Fig. 4 (a))
I _Ry = − (0.5I _FR + 1.5I _FT )
| I _Ry | = | 0.5 I _FR +1.5 I _FT | = | I _FR | (= | I _FT |)
(4) In the case of a short circuit accident between R phase, S phase, and T phase (see FIG. 4B)
I _Ry = −0.5 I _FR + I _FS −1.5 I _FT
| I _Ry | = | −0.5 I _FR +0.5 I _FS −1.5 I _FT |
= {(3 ^1/2 / 2) ² +1.5 ² } ^1/2 × | I _FR |
= 3 ^1/2 × | I _FR | (= 3 ^1/2 × | I _FS | = 3 ^1/2 × | I _FT |)

The overcurrent relay with voltage suppression 50 calculates the corrected short-circuit current I _Ry ′ as follows in order to make the detection sensitivity and the operation time the same for all accident aspects.
(1) In the case of a short-circuit accident between the R phase and the S phase The amplitude of the short circuit current I _{Ry is} the amplitude of the S phase short circuit current I _FS (R phase short circuit current I _FR ). The corrected short-circuit current I _Ry ′ is calculated by multiplying I _Ry by 1.
I _Ry '= I _Ry × 1 = −0.5 I _FR +0.5 I _FS
| I _Ry '| == −− 0.5 I _FR +0.5 I _FS | = | I _FS | (= | I _FR |)
(2) In the case of a short circuit accident between the S phase and the T phase The amplitude of the short circuit current I _Ry is twice the amplitude of the S phase short circuit current I _FS (T phase short circuit current I _FT ). The corrected short-circuit current I _Ry 'is calculated by multiplying the short-circuit current I _Ry by 1/2.
I _Ry '= I _Ry × 1/2 = (0.5I _FS −1.5I _FT ) × 1/2
| I _Ry '| = | 0.5 I _FS −1.5 I _FT | × 1/2 = | I _FS | (= | I _FT |)
(3) In the case of a short-circuit accident between the T phase and the R phase The amplitude of the short circuit current I _{Ry is} the amplitude of the R phase short circuit current I _FR (T phase short circuit current I _FT ). The corrected short-circuit current I _Ry ′ is calculated by multiplying I _Ry by 1.
I _Ry '= I _Ry × 1 = − (0.5 I _FR +1.5 I _FT )
| I _Ry '| = | 0.5 I _FR +1.5 I _FT | = | I _FR | (= | I _FT |)
(4) R-phase -S phase -T phase amplitude when the short-circuit current I _Ry of short circuit of the short-circuit current of the R-phase I _FR (shorts S-phase and T-phase current I _FS, I _FT) 3 of the amplitudes of ^{1 / 2} times. Therefore, the short-circuit current I _Ry as shown in the following equation 1/3 ^1/2 to calculate the correction circuit current I _Ry '.
I _Ry '= I _Ry × 1/3 ^1/2 = (− 0.5 I _FR +0.5 I _FS −1.5 I _FS ) × 1/3 ^1/2
| I _Ry '| = | −0.5I _FR + 0.5I _FS −1.5I _FS | × 1/3 ^1/2
= | I _FR | (= | I _FS | = | I _FT |)

The overcurrent relay with voltage suppression 50 obtains the suppression voltage V _Ry as follows when determining the accident aspect using the first accident aspect determination method described above.
(1) Normal time The R-phase and S-phase line voltage V _RS obtained from the R-phase and S-phase voltages V _R and V _S inputted from the instrument transformer 6 is _defined as a suppression voltage V _Ry .
V _Ry = V _RS
(2) In case of short-circuit accident between R-phase and S-phase R-phase and S-phase line voltage V _RS obtained from R-phase and S-phase phase voltages V _R and V _S input from instrument transformer 6 The suppression voltage is V _Ry .
V _Ry = V _RS
(3) In the case of a short-circuit accident between the S phase and the T phase The S-phase and T-phase line voltage V _ST obtained from the S-phase and T-phase phase voltages V _S and V _T input from the instrument transformer 6 The suppression voltage is V _Ry .
V _Ry = V _ST
(4) In the case of a short-circuit accident between the T phase and the R phase The line voltage V _TR between the T phase and the R phase obtained from the phase voltages V _T and V _{R of the} T phase and the R phase input from the instrument transformer 6 The suppression voltage is V _Ry .
V _Ry = V _TR
(5) In case of short-circuit accident between R phase, S phase, and T phase R-phase and S-phase line voltage obtained from R-phase and S-phase phase voltages V _R and V _S input from instrument transformer 6 Let V _RS be the suppression voltage V _Ry .
V _Ry = V _RS

Further, the overcurrent relay 50 with voltage suppression, when determining the accident aspect using the second or third accident aspect determination method described above, the T-phase and R-phase input from the instrument transformer 6 Using the T-phase to R-phase line voltage V _TR (see FIG. 2B) obtained from the phase voltages V _T and V _R , the suppression voltage V _Ry is obtained as follows according to the accident aspect. Note that V = V _TR ∠ (210 ° + α).
(1) When normal V _Ry = V
(2) In case of short circuit accident between R phase and S phase V _Ry = 2 × V × cos (60 ° + α)
(3) In case of short circuit accident between S phase and T phase V _Ry = 2 × V × cos (60 ° + α)
(4) In case of short-circuit accident between T phase and R phase V _Ry = V
(5) In case of short circuit between R phase, S phase and T phase V _Ry = V

Further, the overcurrent relay 50 with voltage suppression uses the composite voltage V _RS-2T input from the accident aspect determination transformer 110 when determining the accident aspect using the fourth accident aspect determination method described above. The suppression voltage V _Ry is obtained as follows according to the accident aspect.
(1) When normal V _Ry = V _RS-2T
(2) In the case of a short-circuit accident between the R phase and the S phase V _Ry = 110 × (V _RS-2T −83.15) /26.85
(3) In the case of a short circuit accident between the S phase and the T phase V _Ry = 110 × (V _RS-2T −103.94) /6.06
(4) In the case of a short circuit accident between the T phase and the R phase V _Ry = 110 × (V _RS-2T -20.79) /89.21
(5) In case of short circuit between R phase, S phase and T phase V _Ry = V _RS-2T

The overcurrent relay with voltage suppression 50 determines the accident aspect using the fifth accident aspect determination method described above, and the combined voltage V _{R-S +} input from the accident aspect determination transformer 120. _{Using 2T} , the suppression voltage V _Ry is obtained as follows according to the accident aspect.
(1) When normal V _Ry = V _{R-S + 2T}
(2) In the case of a short circuit accident between the R phase and the S phase V _Ry = 110 × (V _{R−S + 2T} −83.15) /26.85
(3) In the case of a short circuit accident between S phase and T phase V _Ry = 110 × (V _{R−S + 2T} −20.79) /89.21
(4) In the case of a short-circuit accident between the T phase and the R phase V _Ry = 110 × (V _{R−S + 2T} −103.94) /6.06
(5) In case of short circuit between R phase, S phase and T phase V _Ry = V _{R-S + 2T}

The overcurrent relay with voltage suppression 50 corrects the current set value determined by the voltage suppression characteristic that defines the magnification of the current set value according to the suppression voltage V _Ry when the amplitude of the correction short-circuit current I _Ry ′ exceeds The first to third circuit breakers 2 ₁ to 2 ₃ are collectively cut off. FIG. 18 shows an example of voltage suppression characteristics.

In the variable composite current transformer 10, the composite current ratio of the currents input from the _first to _third current transformers 3 _{1 to} 3 ₃ is “−0.5: 0.5: −1.5”. Are "-0.5: -1.5: 0.5", "0.5: -0.5: -1.5", "0.5: -1.5: -0.5", It may be “−1.5: 0.5: −0.5” or “−1.5: −0.5: 0.5”.

In the above description, in the variable composite current transformer, the current input from the _first to _third current transformers 3 ₁ to ₃ 3 is expressed as the composite current ratio −0.5: 0.5: −1.5 (the composite current. The ratio is −x ₁ : x ₂ : −x ₃ (x ₁ , x ₂ , x ₃ > 0)), but the combined current ratio ± x ₁ : ± x ₂ : ± x ₃ (x ₁ , x ₂ , may be synthesized in x _3> 0) (e.g., synthetic current ratio _{x 1: x 2: x 3} , the combined current ratio x _1: -x _2: x ₃ or synthetic current ratio -x _1: x _2: - x ₃ may also be used). Here, preferably, at least one of x ₁ , x ₂ and x ₃ is a value different from the others.
Even if the combined current ratio is the same, the values of x ₁ , x ₂ and x ₃ are multiplied by m (for example, the combined current ratio x ₁ : x ₂ : x _{3 is changed} to the combined current ratio mx ₁ : mx ₂ : mx ₃ Thus, the current value of the short-circuit current I _Ry output from the variable composite current transformer can be increased by m times. Further, by reversing the combination of the combined current ratio + and − (for example, the combined current ratio x ₁ : −x ₂ : x _{3 is set} to the combined current ratio −x ₁ : x ₂ : −x ₃ ), The phase of the short-circuit current I _Ry output from the variable composite current transformer can be inverted.

Table 5 shows the amplitude of the short-circuit current I _Ry at the time of the short-circuit accident between the R phase and the S phase when the composite current ratio is changed, the amplitude of the short-circuit current I _Ry at the time of the short-circuit accident between the S phase and the T phase, and the T phase-R. An example of the ratio of the amplitude of the short circuit current I _Ry at the time of the short circuit accident between the phases and the amplitude of the short circuit current I _Ry at the time of the short circuit accident between the R phase, the S phase, and the T phase is shown.

In FIG. 19, the current input from the _first to _third current transformers 3 _{1 to} 3 _{3 is} converted into a composite current ratio of 0.5: 1.0: 1.5 (combined current ratio x in the variable composite current transformer 10. ₁ : x ₂ : x ₃ ) and an example of inputting to the overcurrent relay 4 shown in FIG. From this variable composite current transformer 10, the sum of the current flowing through the R phase of the power transmission and distribution line by 0.5 times, the current flowing through the S phase, and the current flowing through the T phase by 1.5 times is obtained. Is output.

Therefore, the load current I is the current and the S-phase of the load current which is 0.5 times the load current I _R of the R-phase short-circuit accident is input from the variable synthetic current transformer 10 when not occur overcurrent relay 4 I load current I _{T S} and T phases becomes the vector sum of 1.5 times the current, the load current load current of the amplitude of I is R phase I _R (S-phase and T-phase of the load current I _S, I _T ) Of 3 ^1/2 / 2 (see FIG. 20).
I = 0.5I _R + I _S + 1.5I _T
| I | = | 0.5I _R + I _S + 1.5I _T |
= (3 ^1/2 / 2) × | I _R | (= (3 ^1/2 / 2) × | I _S | = (3 ^1/2 / 2) × | I _T |)

In addition, when the short-circuit current that flows in the R-phase, S-phase, and T-phase of the transmission and distribution line when a short-circuit accident occurs is represented by I _FR , I _FS , I _FT , the short-circuit current I _Ry is It is expressed as
(1) In the case of a short-circuit accident between the R phase and the S phase (see FIG. 21A)
I _Ry = 0.5 I _FR + I _FS
| I _Ry | = | 0.5 I _FR + I _FS | = (1/2) × | I _FS | (= (1/2) × | I _FR |)
(2) In the case of a short-circuit accident between the S phase and the T phase (see FIG. 21B)
I _Ry = I _FS + 1.5I _FT
| I _Ry | = | I _FS +1.5 I _FT | = (1/2) × | I _FT | (= (1/2) × | I _FS |)
(3) In the case of a short-circuit accident between the T phase and the R phase (see FIG. 22A)
I _Ry = 0.5I _FR + 1.5I _FT
| I _Ry | = | 0.5 I _FR +1.5 I _FT | = | I _FT | (= | I _FR |)
(4) In case of short circuit between R phase, S phase and T phase (see Fig. 22 (b))
I _Ry = 0.5 I _FR + I _FS +1.5 I _FT
| I _Ry | = | 0.5 I _FR + I _FS +1.5 I _FT |
= (3 ^1/2 / 2) × | I _FR | (= (3 ^1/2 / 2) × | I _FS | = (3 ^1/2 / 2) × | I _FT |)

As described above, the amplitude of the load current I is 3 ^1/2 / 2 times, and the amplitude of the short-circuit current I _Ry in the short-circuit accident between the R phase and the S-phase and the short-circuit accident between the S phase and the T phase is T-phase-R. is 1/2 times the amplitude of the short-circuit current I _Ry in short circuit between the phases, also, short amplitude of the short-circuit current I _Ry in short circuit of the R-phase -S phase -T phase is in a short circuit accident T phase -R phase It becomes 3 ^1/2 / 2 times the amplitude of the current I _Ry . Therefore, in this example, the short-circuit current I _Ry in the short-circuit accident between the load current I and the R-phase / S-phase / T-phase is multiplied by 2/3 ^1/2 , and the short-circuit accident between the R-phase and S-phase and between the S-phase and T-phase of double the short-circuit current I _Ry in short circuit, a short circuit current I _Ry adjustment or correction as multiplying 1 in short-circuit fault of T phase -R phase, all the detection sensitivity and operating time of the short-circuit protection relay Make the same for the accident aspect.

In the fourth accident mode determination method described above, the R-phase phase voltage V _R is doubled in the polarity direction, the S-phase phase voltage V _S in the opposite polarity direction, and the T-phase phase voltage V _T in the opposite polarity direction. The secondary side of the accident aspect determination transformer 110 is connected so as to be combined, and in the fifth accident aspect determination method described above, the phase voltage V _R of the R phase is set in the polarity direction and the phase voltage V _S of the S phase is set. In the opposite polarity direction, the secondary side of the accident phase determination transformer 120 was connected so that the phase voltage V _T of the T phase was doubled and synthesized in the polarity direction, but the phase voltage VR of the _R phase was changed to the polarity direction. Alternatively, multiply by a in the antipolar direction, multiply the S phase voltage V _S by b in the polar or antipolar direction, and synthesize the _T phase voltage V _T by c in the polar or antipolar direction. As such, the secondary side of the transformer for determining an accident aspect may be connected. The composite voltage V _{aR + bS + cT} output from this accident aspect determination transformer is expressed by the following equation.
V _{aR + bS + cT} = ± aV _R ± bV _S ± cV _T

  Although the variable composite current transformer of the present invention has been described above in combination with the short-circuit protective relay used in the transmission and distribution lines, the variable composite current transformer of the present invention is, for example, three for driving the limbs of a robot. The same effect can be obtained even when combined with a short-circuit protection device used in a three-phase AC circuit that supplies power to a phase motor (three-phase load).

It is a figure for demonstrating the protection relay apparatus by 1st Example of this invention. It is a diagram for explaining the load current I and the T-phase -R phase phase voltage V _R of the line voltage V _TR and R-phase when a short circuit does not occur. It is a figure for demonstrating short circuit current _IRy input into the overcurrent relay 4 from the variable synthetic | combination current transformer 10 shown in FIG. 1 when a short circuit accident generate | occur | produces. It is a figure for demonstrating short circuit current _IRy input into the overcurrent relay 4 from the variable synthetic | combination current transformer 10 shown in FIG. 1 when a short circuit accident generate | occur | produces. It is a figure for demonstrating the short circuit current _IRy input into the overcurrent relay 4 when the short circuit accident generate | occur | produces between R phase-S phases of the power transmission and distribution line shown in FIG. It is a figure for demonstrating short circuit current _IRy input into the overcurrent relay 4 when a short circuit accident generate | occur | produces between the S phase-T phases of the power transmission and distribution line shown in FIG. It is a figure for demonstrating short circuit current _IRy input into the overcurrent relay 4 when a short circuit accident generate | occur | produces between the T phase-R phases of the power transmission and distribution line shown in FIG. It is a figure for demonstrating short circuit current _IRy input into the overcurrent relay 4 when a short circuit accident generate | occur | produces between R phase-S phase-T phases of the power transmission and distribution line shown in FIG. It is a figure for demonstrating the protective relay apparatus by the 2nd Example of this invention. It is a figure for demonstrating the protection relay apparatus by the 3rd Example of this invention. It is a figure for demonstrating the protective relay apparatus by the 4th Example of this invention. It is a figure for demonstrating the 2nd accident aspect determination method. It is a figure for demonstrating the 3rd accident aspect determination method. It is a figure which shows the structure of the transformer 110 for an accident aspect determination used in the 4th accident aspect determination method. It is a figure which shows the structure of the transformer 120 for accident aspect determination used in the 5th accident aspect determination method. It is a figure which shows the example of 1 structure of the arithmetic processing part for making detection sensitivity and operation time, such as the overcurrent relay 4 shown in FIG. 1, the same. It is a figure for demonstrating the protective relay apparatus by the 5th Example of this invention. It is a figure which shows an example of a voltage suppression characteristic. The currents input from the _first to _third current transformers 3 _{1 to} 3 ₃ are combined at a combined current ratio of 0.5: 1.0: 1.5 and input to the overcurrent relay 4 shown in FIG. It is the figure which showed the example. It is a figure for demonstrating the load current I input into the overcurrent relay 4 from the variable synthetic | combination current transformer 10 shown in FIG. 19 when the short circuit accident has not generate | occur | produced. It is a figure for demonstrating short circuit current _IRy input into the overcurrent relay 4 from the variable composite current transformer 10 shown in FIG. 19 when a short circuit accident generate | occur | produces. It is a figure for demonstrating short circuit current _IRy input into the overcurrent relay 4 from the variable composite current transformer 10 shown in FIG. 19 when a short circuit accident generate | occur | produces. It is a figure for demonstrating the conventional method which protects from a short circuit accident by installing an overcurrent relay only in two phases by the transmission / distribution line etc. of a terminal circuit.

Explanation of symbols

1 power supply 2 _{1 to} 2 _{6 first} to _sixth circuit breakers 3 ₁ and 3 ₂ first and second current transformers 4 and 30 overcurrent relays 4 ₁ and 4 ₂ first and second overcurrent relays 5 Transformer 6 Instrument transformer 10 Variable composite current transformer 10 ₁ , 10 ₂ First and second variable composite current transformer 20 Current differential relay 50 Overcurrent relay 60 ₁ , 60 ₂ with voltage suppression First and second 2 PCM current differential relays 71 Accident appearance judgment circuits 72 _{1 to} 72 ₃ First to third amplitude adjustment circuits 73 Selection switches 110 and 120 Accident appearance judgment transformers 1L and 2L First and second transmission and distribution lines I, I _R , I _S , I _T load current I ′ corrected load currents i ₁ , I _1R , I _1S , I _1T primary load current i ₂ , I _2R , I _2S , I _2T secondary load current I _a , I _aR , I _aS , I _aT transmitting end load current I _b , I _bR , I _bS , I _bT receiving end load current I _Ry , I _FR , I _FS , I _FT short Fault current I _Ry 'Corrected short-circuit current V _R , V _S , V _T phase voltage V _RS , V _ST , V _TR line voltage V _RS-2T , V _{R-S + 2T} composite voltage V _Ry suppression voltage S _SW switch control Signal θ Impedance angles k1, k2 First and second voltage values α, β Angle ranges γ, δ First and second angle ranges K _{1 to} K ₈ First to eighth combined voltage values ε _{1 to} ε ₈ First to eighth combined voltage angle ranges λ _{1 to} λ ₈ First to eighth short-circuit current angle ranges

Claims (16)

A variable combined current transformer for detecting a short-circuit current flowing in the first to third phases of the three-phase AC circuit, wherein the short-circuit current flowing in the first to third phases is a combined current ratio ± x ₁ : ± x ₂ : A variable synthesis current transformer characterized by synthesis at ± x ₃ (x ₁ , x ₂ , x ₃ > 0). A variable composite current transformer (10, 10 ₁ , 10 ₂ ) for detecting a short-circuit current flowing in the first to third phases of a three-phase AC circuit, the short-circuit flowing in the first to third phases The combined current ratio x ₁ : x ₂ : x ₃ , the combined current ratio x ₁ : −x ₂ : x ₃ or the combined current ratio −x ₁ : x ₂ : −x ₃ (x ₁ , x ₂ , x ₃ > 0), a variable synthesis current transformer characterized by synthesis.   Computation processing means is provided for determining the accident aspect of the short circuit accident of the three-phase AC circuit and multiplying the short circuit current detected by the variable composite current transformer by a predetermined multiple according to the determination result of the accident aspect. The variable composite current transformer according to claim 1 or 2, characterized in that A protective relay device for protecting a three-phase AC circuit from a short circuit accident,
A variable composite current transformer according to any one of claims 1 to 3,
A short-circuit protection relay that collectively shuts off the circuit breakers installed in the first to third phases of the three-phase AC circuit when a short-circuit fault is detected based on a short-circuit current input from the variable composite current transformer;
A protective relay device comprising: The protective relay device is
Accident aspect determining means for determining the accident aspect of the short circuit accident of the three-phase AC circuit;
Arithmetic processing means for multiplying the short-circuit current detected by the variable composite current transformer by a predetermined multiple according to the determination result of the accident aspect in the accident aspect determination means;
The protective relay device according to claim 4, further comprising: The accident mode determination means determines whether the three-phase AC circuit has three line voltages (V _RS , V _ST , V _TR ), three phase voltages (V _R , V _S , V _T ), or a phase / line voltage. 6. The protective relay device according to claim 5, wherein an accident aspect of a short-circuit accident of the three-phase AC circuit is determined based on the basis. The accident mode determination means is based on the voltage value and phase of one line voltage (V _RS , V _ST , V _TR ) and one phase voltage (V _R , V _S , V _T ) of the three-phase AC circuit. 6. The protective relay device according to claim 5, wherein an accident aspect of a short circuit accident of the three-phase AC circuit is determined. The accident mode judging means is configured to _detect a voltage value and a phase of one line voltage (V _RS , V _ST , V _TR ) of the three-phase AC circuit and a short circuit current (I _Ry ) input from the variable composite current transformer. 6. The protective relay device according to claim 5, wherein an accident aspect of a short circuit accident of the three-phase AC circuit is determined based on the phase of the three-phase AC circuit. The first phase voltage (V _R ) of the three-phase AC circuit is in the polarity direction, and the second phase voltage (V _S ) of the three-phase AC circuit is in the opposite polarity direction. The first to second phases are used for determining the accident aspect of the short-circuit fault of the three-phase AC circuit, where the secondary side is connected so as to synthesize the phase voltage (V _T ) by doubling in the opposite polarity direction. An accident mode judging transformer (110) for obtaining a composite voltage (V _RS-2T ) of the phase voltages of the three phases;
The accident aspect determination means is based on the voltage value and phase of the composite voltage input from the accident aspect determination transformer and the phase of the short-circuit current (I _Ry ) input from the variable composite current transformer. Determine the accident aspect of the short circuit accident of the three-phase AC circuit,
The protective relay device according to claim 5. The first phase voltage (V _R ) of the three-phase AC circuit is in the polarity direction, and the second phase voltage (V _S ) of the three-phase AC circuit is in the opposite polarity direction. The first to third are used for determining the accident aspect of the short-circuit accident of the three-phase AC circuit in which the secondary side is connected so that the phase voltage (V _T ) is doubled and synthesized in the polarity direction. An accident mode judging transformer (120) for obtaining a composite voltage (V _{R-S + 2T} ) of the phase voltage of
The accident aspect determination means is based on the voltage value and phase of the composite voltage input from the accident aspect determination transformer and the phase of the short-circuit current (I _Ry ) input from the variable composite current transformer. Determine the accident aspect of the short circuit accident of the three-phase AC circuit,
The protective relay device according to claim 5. The first phase voltage (V _R ) of the three-phase AC circuit is multiplied by a in the polarity direction or the antipolar direction, and the second phase voltage (V _S ) of the three-phase AC circuit is changed in the polarity direction or antipolar direction. And the secondary side is connected so that the third phase voltage (V _T ) of the three-phase AC circuit is multiplied by c in the polarity direction or the opposite polarity direction to be combined, and the three-phase AC A _fault condition determining transformer for obtaining a composite voltage (V _{aR + bS + cT} ) of the first to third phase voltages used for determining an accident aspect of a short circuit accident of a circuit;
The accident aspect determination means is based on the voltage value and phase of the composite voltage input from the accident aspect determination transformer and the phase of the short-circuit current (I _Ry ) input from the variable composite current transformer. Determine the accident aspect of the short circuit accident of the three-phase AC circuit,
The protective relay device according to claim 5. The variable synthesis current transformer synthesizes the currents input from the _first to _third current transformers (31 to 3 ₃ ) installed in the first to third phases of the transmission and distribution lines, respectively. A current transformer (10),
When the short-circuit protection relay detects a short-circuit fault based on the short-circuit current (I _Ry ) input from the variable composite current transformer, the first short-circuit protection relay is installed in each of the first to third phases of the transmission and distribution line. An overcurrent relay (4) that collectively cuts off the _first to _third circuit breakers (2 ₁ to 2 ₃ );
The protective relay device according to claim 4, wherein The variable composite current transformer is input from _first to _third current transformers (3 _{1 to} 3 ₃ ) installed in the first to third phases on the primary side of the transformer (5), respectively. A first variable current transformer (10 ₁ ) for combining currents, and fourth to sixth current transformers (3) installed in the first to third phases on the secondary side of the transformer, respectively. _{4 to} 3 ₆ ) and a second variable current transformer (10 ₂ ) for synthesizing the current input from
When the short-circuit protection relay detects a short-circuit accident based on a difference current between a short-circuit current input from the first variable composite current transformer and a short-circuit current input from the second variable composite current transformer, First to third circuit breakers (2 ₁ to 2 ₃ ) respectively installed in the first to third phases on the primary side of the transformer and the _first to _third circuit breakers on the secondary side of the transformer A current differential relay (20) that collectively cuts off the _fourth to _sixth circuit breakers (2 ₄ to 2 ₆ ) respectively installed in the three phases;
The protective relay device according to claim 4, wherein The variable composite current transformer is input from _first to _third current transformers (3 _{1 to} 3 ₃ ) installed in the first to third phases of the first transmission and distribution line (1L), respectively. The first variable current transformer (10 ₁ ) for synthesizing currents and the fourth to sixth current transformers installed in the first to third phases of the second transmission / distribution line (2L), respectively. (at 3 _{4-3 6)} second variable synthesizing current transformer for combining a current input (10 ₂₎ and,
When the short-circuit protection relay detects a short-circuit accident based on a sum current of a short-circuit current input from the first variable composite current transformer and a short-circuit current input from the second variable composite current transformer, The first to third circuit breakers (2 ₁ to 2 ₃ ) installed in the first to third phases of the first transmission / distribution line and the _first to _{third of} the second transmission / distribution line, respectively. An overcurrent relay (30) that collectively disconnects the _fourth to _sixth circuit breakers (2 ₄ to 2 ₆ ) respectively installed in the phases of
The protective relay device according to claim 4, wherein: Current input from the _first to _third current transformers (3 _{1 to} 3 ₃ ) installed in the first to third phases of the transmission / distribution line on the power supply end bus side of the variable composite current transformer A first variable current transformer (10 ₁ ) for synthesizing the power supply, and fourth to sixth current transformers (10 ₁ ) installed in the first to third phases of the transmission and distribution lines on the power receiving end bus side ( 3 _{4 to} 3 ₆ ) and a second variable synthesis current transformer (10 ₂ ) for synthesizing the current input from
When the short-circuit protection relay detects a short-circuit accident based on a difference current between a short-circuit current input from the first variable composite current transformer and a short-circuit current input from the second variable composite current transformer, The _first to _third circuit breakers (2 ₁ to 2 ₃ ) installed in the first to third phases of the transmission / distribution line on the power supply end bus side and the transmission / distribution line on the power reception end bus side First and second pulse code modulation current differential relays (60 ₁ , 60 ₁ , 60) that collectively shut off the _fourth to _sixth circuit breakers (2 ₄ to 2 ₆ ) respectively installed in the first to third phases. 60 ₂ ),
The protective relay device according to claim 4, wherein: The variable synthesis current transformer synthesizes the currents input from the _first to _third current transformers (31 to 3 ₃ ) installed in the first to third phases of the transmission and distribution lines, respectively. A current transformer (10),
The short-circuit protection relay uses a suppression voltage (V _R , V _ST , V _TR ) calculated using a short-circuit current (I _Ry ) input from the variable composite current transformer and a line voltage (V _RS , V _ST , V _TR ) of the transmission / distribution line. _Ry ) and a voltage that collectively shuts off the _first to _third circuit breakers (2 ₁ to 2 ₃ ) respectively installed in the first to third phases of the transmission and distribution line. An overcurrent relay with suppression (50),
The protective relay device according to claim 4, wherein: