JP2009050147A - Overcurrent relay apparatus with voltage suppression function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overcurrent relay apparatus with voltage suppression function capable of more reducing the numbers of current transformers and overcurrent relays with voltage suppression function for protecting a three-phase alternating-current circuit from a damage by a short-circuit. <P>SOLUTION: The overcurrent relay apparatus with the voltage suppression function is equipped with a through current transformer 10 where crossing currents pass, designed to be passed with the R and S phases of a power distribution cable reversely in an arbitrary angle through an annular iron core with a secondary coil wound around it; and an overcurrent relay 50 with the voltage reduction function capable of collectively breaking first to third breakers 2<SB>1</SB>to 2<SB>3</SB>mounted in each phase of a power distribution cable when short-circuit damages are detected, based on a short-circuit current I<SB>Ry</SB>inputted from the through current transformer 10 where crossing currents pass and a line to line voltage V<SB>TR</SB>in T to R phases and a phase voltage V<SB>R</SB>in an R phase obtained from voltage data via an instrument transformer 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an overcurrent relay device with voltage suppression, and in particular, voltage suppression suitable for reducing the number of installed current transformers and overcurrent relays with voltage suppression for protecting a three-phase AC circuit from a short circuit accident. The present invention relates to an overcurrent 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, if the detection of a short-circuit accident is performed only with the current value, the load current and the short-circuit current may not be distinguished. Therefore, the overcurrent relay with voltage suppression has a function of correcting the current detection sensitivity according to the voltage value. Is used.

For example, as shown in FIG. 9, the _first to _third current transformers (CT) 3 ₁ to ₃ 3 installed in the R-phase, S-phase, and T-phase of the transmission / distribution lines are connected to the _first to _third current transformers. Overcurrent relays with voltage suppression (OCV) 4 ₁ to 4 ₃ are connected to each other, and from the transformer for instrument 6 installed on the bus, the first overcurrent relay with voltage suppression 4 ₁ has an R phase-S phase. of the line enter the voltage V _RS, the ₂ second overcurrent relay with voltage suppression 4 enter the line voltage V _ST of S phase -T phase, the third voltage suppression with overcurrent relay 4 ₃ inputs the line voltage V _TR of the T-phase -R phase, when the short circuit occurs in the electric transmission, the first to third biasing voltage suppression overcurrent relay 41 _{to 3} in accordance with the accident appearance operates as follows, R-phase of the transmission and distribution lines, to collectively block the first through third circuit breaker 2 ₁ to 2 ₃ of which are respectively installed on the S-phase and T-phase It is.
(1) In the case of a short-circuit accident between the R phase and the S phase A short circuit current flows in the R phase and the S phase of the transmission and distribution line, and the line voltage V _RS between the R phase and the S phase and the line voltage V between the S phase and the T phase. _{Since ST} occurs, the first and second overcurrent relays 4 ₁ , 4 ₂ with voltage suppression operate to collectively cut off the _first to _third circuit breakers 2 ₁ to 2 ₃ .
(2) In the case of a short circuit accident between the S phase and the T phase A short circuit current flows in the S phase and T phase of the transmission and distribution line, and the S phase-T phase line voltage V _ST and the T phase-R phase line voltage V _{Since TR} occurs, the second and third overcurrent relays with voltage suppression 4 ₂ and 4 ₃ operate to collectively cut off the _first to _third circuit breakers 2 ₁ to 2 ₃ .
(3) Short-circuit accident between T-phase and R-phase Short-circuit current flows in the R-phase and T-phase of the transmission and distribution line, and the R-S phase line voltage V _RS and the T-phase-R phase line voltage V _{Since TR} occurs, the first and third overcurrent relays 4 ₁ , 4 ₃ with voltage suppression operate to collectively cut off the _first to _third circuit breakers 2 ₁ to 2 ₃ .
(4) In the case of a short circuit accident between R phase, S phase and T phase Short circuit current flows in R phase, S phase and T phase, line voltage V _RS between R phase and S phase, and line between S phase and T phase Since the voltage V _ST and the T-phase to R-phase line voltage V _TR are generated, the _first to _third overcurrent relays 4 ₁ to 4 ₃ with voltage suppression operate and the _first to _third circuit breakers 2 ₁ collectively shut off to 2 _3.

Moreover, in the power transmission / distribution line of the terminal circuit, etc., the short circuit current flows in two phases, and the overcurrent relay with voltage suppression is installed only in the two phases to reduce the equipment cost. For example, as shown in FIG. 10, the first and second current transformers 3 ₁ and 3 ₂ respectively installed in the R phase and the T phase among the R phase, S phase, and T phase of the transmission / distribution line are firstly connected. And the second overcurrent relay with voltage suppression 4 ₁ , 4 ₂ are connected to each other, and from the transformer 6 for the instrument installed on the bus, the first overcurrent relay with voltage suppression 4 ₁ is connected to the R-phase-S. enter the line voltage V _RS phases, the ₂ second overcurrent relay with voltage suppression 4 to input line voltage V _TR of the T-phase -R phase, when the short circuit occurs in the electric transmission The first and second voltage suppression overcurrent relays 4 ₁ , 4 ₂ operate as follows according to the accident situation, and are installed in the R phase, S phase and T phase of the transmission and distribution lines, respectively. The first to third circuit breakers 2 ₁ to 2 ₃ are collectively cut off.
(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 of the transmission and distribution line and a line voltage V _RS between the R phase and the S phase is generated, the first overcurrent relay with voltage suppression 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 the S phase and the T phase Since a short circuit current flows in the T phase of the transmission and distribution line and a line voltage V _TR between the T phase and the R phase is generated, the second overcurrent relay with voltage suppression 4 ₂ operates to collectively shut off the _first to _third circuit breakers 2 ₁ to 2 ₃ .
(3) Short-circuit accident between T-phase and R-phase Short-circuit current flows in the R-phase and T-phase of the transmission and distribution line, and the R-S phase line voltage V _RS and the T-phase-R phase line voltage V _{Since TR} occurs, the first and second overcurrent relays with voltage suppression 4 ₁ and 4 ₂ operate to collectively cut off 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 A short circuit current flows in the R phase and the T phase, and the line voltage V _RS between the R phase and the S phase and the line voltage V _TR between the T phase and the R phase. Therefore, the first and second overcurrent relays with voltage suppression 4 ₁ , 4 ₂ operate to collectively cut off the _first to _third circuit breakers 2 ₁ to 2 ₃ .
JP-A-8-005659

However, since two or three current transformers and overcurrent relays with voltage suppression are installed for each transmission and distribution line, there are the following problems.
(1) There is a demand to reduce the installation cost by further reducing the number of installed current transformers and overcurrent relays with voltage suppression.
(2) If the number of overcurrent relays with voltage suppression is two, it is possible to protect the three-phase AC circuit from a short circuit accident of its own circuit, but an overcurrent relay with voltage suppression is installed. Short circuit accidents that do not extend to other phases and other circuits cannot be detected, and the three-phase AC circuit is protected by the short-circuit protection relay on the power supply side, thus expanding the range of power outages.
(3) When the number of overcurrent relays with voltage suppression is two, if one overcurrent relay with voltage suppression is not usable due to failure or inspection, the three-phase AC circuit is protected from a short-circuit accident. I can't do that.

  An object of the present invention is to provide an overcurrent relay device with voltage suppression that can further reduce the number of installed current transformers and overcurrent relays with voltage suppression for protecting a three-phase AC circuit from a short circuit accident. It is in.

The overcurrent relay device with voltage suppression of the present invention is an overcurrent relay device with voltage suppression for protecting a three-phase AC circuit from a short circuit accident, and the three-phase is mounted on an annular core wound with a secondary coil. A cross-through current transformer (10; 10 ₁ ) in which two arbitrary phases of the AC circuit are crossed in opposite directions and at an arbitrary angle, and a short-circuit current (I _Ry ) input from the cross-through current transformer ; _Ry1 ) and the voltage information of the three-phase AC circuit, when a short-circuit accident is detected, _first to _third circuit breakers (2 ₁ to 2 ₃ ) installed in the respective phases of the three-phase AC circuit And an overcurrent relay with voltage suppression (50; 50 ₁ ) that collectively cuts off the power supply.
Here, an accident mode determination unit that determines an accident mode of the short circuit accident of the three-phase AC circuit, and the short circuit that is input from the cross-through current transformer according to the determination result of the accident mode in the accident mode determination unit A correction short circuit current calculating means for calculating a correction short circuit current (I _Ry '; I _Ry1 ') by multiplying the current by a predetermined multiple may be further provided.
The overcurrent relay with voltage suppression calculates a suppression voltage (V _Ry ) using voltage information of the three-phase AC circuit according to the determination result of the accident mode in the accident mode determination means, and the calculated suppression voltage The first to third circuit breakers may be collectively cut off when the calculated corrected short-circuit current amplitude exceeds a current set value determined by a voltage suppression characteristic that defines a current set value according to .
One phase of the arbitrary two phases of the three-phase AC circuit and one other phase other than the arbitrary two phases are crossed in an opposite direction and at an arbitrary angle on an annular core around which a secondary coil is wound. On the basis of the other cross-through current transformer (10 ₂ ) penetrated through, the other short-circuit current (I _Ry2 ) input from the second cross-through current transformer, and the voltage information of the three-phase AC circuit. When a short circuit accident is detected, another overcurrent relay with voltage suppression (50 ₂ ) that collectively shuts off the first to third circuit breakers may be further provided.
In addition, the accident mode judging means may be configured such that three line voltages (V _RS , V _ST , V _TR ), three phase voltages (V _R , V _S , V _T ) or phase / line between the three-phase AC circuits. You may determine the accident aspect of the short circuit accident of this three-phase alternating current circuit based on a voltage.
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 determination means determines the voltage value and phase of one line voltage (V _RS , V _ST , V _TR ) of the three-phase AC circuit and the phase of the short-circuit current input from the cross-through current transformer. Based on this, the accident aspect of the short circuit accident of the three-phase AC circuit may be determined.
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 determination transformer (110) for obtaining a composite voltage (V _RS-2T ) of the phase voltages of the three phases, wherein the accident mode determination means is input from the accident mode determination 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 input from the cross-through 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 determination transformer (120) for obtaining a composite voltage (V _{R-S + 2T} ) of the phases of the phases, and the accident mode determination means is input from the accident mode determination 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 input from the cross-through 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 judging transformer for obtaining a composite voltage (V _{aR + bS + cT} ) of the phase voltages of the first to third phases used for judging the accident situation of the short circuit accident of the circuit; The three-phase AC circuit based on the voltage value and phase of the composite voltage input from the accident mode determination transformer and the phase of the short circuit current input from the cross-through current transformer, wherein the accident mode determination means The accident aspect of the short circuit accident may be determined.

The overcurrent relay device with voltage suppression of the present invention has the following effects.
(1) By using a cross-through current transformer, the number of installed current transformers and overcurrent relays with voltage suppression can be further reduced, and the equipment cost can be reduced.
(2) By using two cross-through current transformers and two overcurrent relays with voltage suppression, it is possible to reliably detect even a short-circuit accident that spans its own circuit and other circuits. Expansion can be prevented.
(3) By using two cross-through current transformers and two overcurrent relays with voltage suppression, even if one overcurrent relay with voltage suppression cannot be used due to failure or inspection, a short circuit accident in its own circuit Since it can back up by another one overcurrent relay with voltage suppression, a three-phase alternating current circuit can be protected from a short circuit accident.

  For the above purpose, a cross-through current transformer in which any two phases of a three-phase power transmission and distribution line are crossed in an opposite direction and at an arbitrary angle through an annular iron core wound with a secondary coil, When the overcurrent relay with voltage suppression detects a short-circuit accident based on the short-circuit current input from the cross-through current transformer and the voltage information of the transmission and distribution line, the first to the first installed in each phase of the transmission and distribution line This was realized by shutting off all three circuit breakers at once.

Embodiments of an overcurrent relay device with voltage suppression according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the overcurrent relay device with voltage suppression according to the first embodiment of the present invention includes a cross through current transformer 10 that is penetrated so that the R phase and the S phase of the transmission and distribution line cross each other. T phase obtained from short circuit current I _Ry input from cross through current transformer 10 and voltage information (R phase, S phase, and T phase phase voltages) input from instrument transformer 6 installed on the bus -When a short circuit accident of the transmission / distribution line is detected based on the line voltage V _TR of the R phase and the phase voltage V _R of the R phase, the first installed in the R phase, S phase, and T phase of the transmission / distribution line, respectively or comprises a third circuit breaker 2 ₁ to 2 ₃ voltage overcurrent relay 50 with suppressed for collectively blocking the.

Here, the cross-through current transformer 10 is a through-type current transformer in which an R-phase and an S-phase of a transmission / distribution line are crossed in an opposite direction and at an arbitrary angle through an annular core around which a secondary coil is wound. It is.
That is, the R phase of the transmission / distribution line is penetrated in the polarity direction of the cross-through current transformer 10 (the direction from the first opening surface of the annular core) to the second opening surface of the annular core. The S phase of the electric wire is penetrated in the opposite polarity direction of the cross through current transformer 10 (direction from the second opening surface of the annular core to the first opening surface of the annular core).

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 , I _T , the R-phase load current I _R and the S-phase As shown in FIG. 2 (a), the load current I _{S of the} current flows through the annular core of the cross-through current transformer 10 in a reverse direction with a phase difference of 120 ° (that is, the R-phase load current I _R is The cross-through current transformer 10 flows through in the polarity direction, and the S-phase load current I _S flows through the cross-through current transformer 10 in the opposite polarity direction). Therefore, the load current I input from the cross-through current transformer 10 to the overcurrent relay 50 with voltage suppression is a vector difference between the R-phase load current I _R and the S-phase load current I _S, and the amplitude of the load current I Is 3 ^1/2 times the amplitude of the R-phase load current I _R (S-phase load current I _S ).
I = I _R −I _S
| I | = | I _R −I _S | = 3 ^1/2 × | I _R | = 3 ^1/2 × | I _S |
Thus, since the amplitude of the load current I is 3 ^1/2 times the amplitude of the R-phase load current I _R (S-phase load current I _S ), the overcurrent relay 50 with voltage suppression is given by As shown, the load current I is multiplied by 1/3 ^1/2 to calculate a corrected load current I ′.
I '= I / 3 ^1/2
| I ′ | = | I | / 3 ^1/2 = | I _R | = | I _S |

  The overcurrent relay with voltage suppression 50 determines the occurrence of a short circuit accident and the accident aspect using any one of the following first to fifth accident aspect determination methods.

(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 reference to the phase = 210 ° (+ (α)), it is determined that there is a short circuit accident between the R phase and the S phase (FIG. 3 ( 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. 3). (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. 3C).
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. 3D). 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, which will be described later, 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 input from the cross-through current transformer.

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 reference to the phase = 210 °, it is determined that the short-circuit accident occurs between the R phase and the S phase (FIG. 11 ( 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 reference to the phase = 210 °, it is determined that there is a short circuit accident between the S phase and the T phase (FIG. 11). (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. 11C).
(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. 11D).

(Fourth accident mode determination method)
The accident mode determination transformer 110 shown in FIG. 12 is installed on the bus, and based on the voltage value and phase of the composite voltage V _RS-2T output from the accident mode determination transformer 110 and the phase of the short-circuit current, Determine the accident aspect 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 is from 90 ° (−45 °) to 90 ° (+ 15 °) which is the maximum angle at the time of a short-circuit accident in consideration of arc resistance. To do.

(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 ) (see equations (2-2) and (2-3)) (+ ε ₁ ) and short circuit When the phase of the current is within the predetermined first short-circuit current angle range λ ₁ (−19.1 ° ≦ λ ₁ ≦ 40.9 °), it is determined that a short-circuit accident between the R phase and the S phase occurs.
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 / 100.05)
= 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 is advanced only within a predetermined second short-circuit current angle range λ ₂ (19.1 ° ≦ λ ₂ ≦ 79.1 °) (−λ ₂ ), a short circuit between the S phase and the T phase Judge as an 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 is delayed (+ λ ₃ ) by a predetermined third short-circuit current angle range λ ₃ (40.9 ° ≦ λ ₃ ≦ 100.9 °), a short-circuit accident between the T phase and the R phase Is determined.
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 less than or equal to the 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 is a predetermined fourth value. Is within the short-circuit current angle range λ ₄ (−19.1 ° ≦ λ ₄ ≦ 40.9 °), it is determined as a short-circuit accident between the R phase, the S phase, and the T phase.

(Fifth accident mode determination method)
An accident mode determination transformer 120 shown in FIG. 13 is installed on the bus, and based on the voltage value and phase of the composite voltage V _{R-S + 2T} output from the accident mode determination transformer 120 and the phase of the short circuit current. The accident aspect is judged 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 is from 90 ° (−45 °) to 90 ° (+ 15 °) which is the maximum angle at the time of a short-circuit accident in consideration of arc resistance. To do.

(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 is delayed by (+ λ ₅ ) within a predetermined fifth short-circuit current angle range λ ₅ (79.1 ° ≦ λ ₅ ≦ 139.1 °) (+ λ ₅ ) -Judged as a short circuit accident between S phases.
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 when the phase of the short-circuit current is delayed (+ λ ₆ ) by a predetermined sixth short-circuit current angle range λ ₆ (19.1 ° ≦ λ ₆ ≦ 79.1 °) (S phase − It is determined as a short-circuit accident between T phases.
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 when the phase of the short-circuit current is delayed by (+ λ ₇ ) within a predetermined seventh short-circuit current angle range λ ₇ (139.1 ° ≦ λ ₇ ≦ 199.1 °) Judged as a short circuit accident between R phases.
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 equal to or less than a predetermined eighth composite voltage value K ₈ = 85 V (75 to 80% of the rated voltage) 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 ° Voltage angle range ε ₈ (−7.10 ° (= −X ₇ ) ≦ ε ₈ ≦ 3.09 ° (= X ₉ )) (that is, in phase) and the short-circuit current Short-circuit accident between R phase, S phase, and T phase when the phase is delayed by (+ λ ₈ ) within a predetermined eighth short-circuit current angle range λ ₈ (79.1 ° ≦ λ ₈ ≦ 139.1 °) Is determined.

When the overcurrent relay with voltage suppression 50 determines that a short-circuit accident has occurred, the overcurrent relay 50 with voltage suppression calculates a corrected short-circuit current I _Ry ′ according to the determination result of the accident aspect as follows.

(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 power 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 input from the cross-through current transformer 10 to the overcurrent relay 50 with voltage suppression is the short-circuit current I _FR of the R phase and the short-circuit current of the S-phase as indicated by the solid thick arrow in FIG. This is a vector difference from I _FS, and the amplitude of the short-circuit current I _Ry is twice the amplitude of the R-phase short-circuit current I _FR (S-phase short-circuit current I _FS ) (see FIG. 4A). , The short-circuit currents I _FR , I _FS , and I _FT flowing in the inner direction of the transmission / distribution line are solid arrows, and the short-circuit currents I _FR , I _FS , and I _FT flowing in the outer direction of the transmission / distribution line are dashed-dotted arrows And θ represents the impedance angle of the short-circuit currents I _FR , I _FS , and I _FT .)
I _Ry = I _FR −I _FS
| I _Ry | = | I _FR −I _FS | = 2 × | I _FR | = 2 × | I _FS |
Thus, since the amplitude of the short-circuit current I _Ry is twice the amplitude of the R-phase short-circuit current I _FR (S-phase short-circuit current I _FS ), the overcurrent relay 50 with voltage suppression is expressed by the following equation: The corrected short-circuit current I _Ry ′ is calculated by multiplying the short-circuit current I _Ry by ½.
I _Ry '= I _Ry / 2
| I _Ry '| = | I _Ry | / 2 = | I _FR | = | I _FS |
(2) In the case of a short-circuit accident between the S phase and the T phase When a short circuit accident between the S phase and the T phase occurs, the S phase short circuit current I _FS flows in the S phase of the transmission and distribution line in the internal direction, and the T of the transmission and distribution line Although the T-phase short-circuit current I _FT flows in the external direction in the phase, the R-phase short-circuit current I _FR does not flow in the R-phase of the transmission and distribution line.
Therefore, the short-circuit current I _Ry input from the cross-through current transformer 10 to the overcurrent relay 50 with voltage suppression becomes the S-phase short-circuit current −I _FS having a negative polarity, and the amplitude of the short-circuit current I _Ry is the S-phase amplitude. The amplitude of the short-circuit current I _FS (see FIG. 4B).
I _Ry = −I _FS
| I _Ry | = | I _FS |
Thus, since the amplitude of the short-circuit current I _Ry becomes the amplitude of the S-phase short-circuit current I _FS , the overcurrent relay 50 with voltage suppression increases the short-circuit current I _Ry by 1 as shown in the following equation and corrects the short-circuit. The current I _Ry 'is calculated.
I _Ry '= I _Ry
| I _Ry '| = | I _FS |
(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, a T phase short circuit current I _FT flows in the T phase of the transmission and distribution line, and the R of the transmission and distribution line. While the short-circuit current I _FR of R-phase to phase flows 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 input from the cross-through current transformer 10 to the overcurrent relay 50 with voltage suppression becomes the R-phase short-circuit current I _FR , and the amplitude of the short-circuit current I _Ry is the R-phase short-circuit current I _FR . It becomes an amplitude (see FIG. 4C).
I _Ry = I _{FR
| I Ry | = | I FR} |
Thus, since the amplitude of the short-circuit current I _Ry becomes the amplitude of the R-phase short-circuit current I _FR , the overcurrent relay with voltage suppression 50 corrects the short-circuit by multiplying the short-circuit current I _Ry by 1 as shown in the following equation. The current I _Ry 'is calculated.
I _Ry '= I _Ry
| I _Ry '| = | I _FR |
(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, short circuit current I of R phase to R phase, S phase, and T phase of the transmission and distribution line _FR and S-phase short-circuit current I _FS and T-phase short-circuit current I _FT flow in the internal direction with a phase difference of 120 °.
Therefore, the short-circuit current I _Ry input from the cross-through current transformer 10 to the overcurrent relay 50 with voltage suppression becomes a vector difference between the R-phase short-circuit current I _FR and the S-phase short-circuit current I _FS, and the short-circuit current I _Ry Is 3 ^1/2 times the amplitude of the R-phase short-circuit current I _FR (S-phase short-circuit current I _FS ) (see FIG. 4D).
I _Ry = I _FR −I _FS
| I _Ry | = | I _FR −I _FS | = 3 ^1/2 × | I _FR | = 3 ^1/2 × | I _FS |
Thus, the amplitude of the short-circuit current I _Ry is 3 ^1/2 times the amplitude of the R-phase short-circuit current I _FR (S-phase short-circuit current I _FS ). As shown, the short-circuit current I _Ry is multiplied by 1/3 ^1/2 to calculate a corrected short-circuit current I _Ry '.
I _Ry '= I _Ry / 3 ^1/2
| I _Ry '| = | I _Ry | / 3 ^1/2 = | I _FR | = | I _FS |

Furthermore, when the overcurrent relay with voltage suppression 50 determines that a short circuit accident has occurred, it calculates the suppression voltage V _Ry according to the determination result of the accident aspect as follows.

When the accident aspect is determined using the first accident aspect determination method described above, the suppression voltage V _Ry is obtained as follows.
(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

When the accident aspect is determined using the second or third accident aspect determination method described above, T obtained from the phase voltages V _T and V _{R of the} T phase and the R phase input from the instrument transformer 6 is used. Using the phase-R phase line voltage V _TR (see FIG. 2B), the suppression voltage V _Ry is obtained as follows according to the accident aspect.
(1) When normal V _Ry = V
Here, V = V _TR ∠210 °
(2) In case of short circuit accident between R phase and S phase V _Ry = 2 × V × cos (60 ° + α)
Here, V = V _TR ∠ (210 ° + α)
(3) In case of short circuit accident between S phase and T phase V _Ry = 2 × V × cos (60 ° + α)
Here, V = V _TR ∠ (210 ° −α)
(4) In case of short-circuit accident between T phase and R phase V _Ry = V
Here, V = V _TR ∠210 °
(5) In case of short circuit between R phase, S phase and T phase V _Ry = V
Here, V = V _TR ∠210 °

When the accident aspect is determined using the above-described fourth accident aspect determination method, the composite voltage V _RS-2T input from the accident aspect determination transformer 110 is used, according to the accident aspect, as follows. Thus, the suppression voltage V _Ry is obtained.
(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

When the accident aspect is determined using the above-described fifth accident aspect determination method, the composite voltage V _{R-S + 2T} input from the accident aspect determination transformer 120 is used to determine the accident aspect according to the accident aspect. Thus, the suppression voltage V _Ry is obtained.
(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. 5 shows an example of voltage suppression characteristics.

Next, an overcurrent relay device with voltage suppression according to a second embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 6, the overcurrent relay device with voltage suppression according to the present embodiment includes a first cross through current transformer 10 ₁ that is penetrated so that the R phase and the S phase of the transmission and distribution lines cross each other, A second cross through current transformer 10 ₂ that is penetrated so that the R phase and T phase of the power transmission and distribution line cross each other, and a first short-circuit current I _Ry1 that is input from the first cross through current transformer 10 _1. And T-R phase voltage V _TR and R-phase voltage V _R obtained from the voltage information input from the voltage transformer 6 installed on the bus, When detected, the first overcurrent relay 50 ₁ with voltage suppression 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, voltage information input from the second short-circuit current I _Ry2 and instrument transformer 6 which is input from the second cross through current transformer 10 ₂ When a short circuit accident of the transmission / distribution line is detected based on the T-phase to R-phase line voltage V _TR and the R-phase phase voltage V _R obtained from the information, the _first to _third circuit breakers 2 ₁ to 2 ₃ And a second overcurrent relay with voltage suppression 50 ₂ that collectively cuts off the power.

Here, the first cross through the current transformer 10 _1, through which is passed through by a cross at any angle and R-phase and S-phase of the transmission and distribution lines to the annular core formed by winding a secondary coil in the opposite direction forms a current transformer, a second cross through current transformer 10 _2, by the cross at any angle and R-phase and T-phase of the transmission and distribution lines to the annular core formed by winding a secondary coil in the opposite direction This is a through-type current transformer.
Ie, R-phase of the electric transmission has been through the first polarity direction of the cross through the current transformer 10 _1, S-phase first opposite polarity direction of the cross through the current transformer 10 _first transmission and distribution lines It is penetrated by. Similarly, R-phase of the electric transmission has been through the second polarity direction of the cross through the current transformer 10 _2, T-phase of the electric transmission a second opposite polarity cross the through current transformer 10 ₂ Penetrated in the direction.

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 , as shown in FIG. because the load current I _S of the current I _R and S-phase flow through the first cross through the current transformer 10 _first annular core with a phase difference of 120 °, the first cross through current transformer 10 ₁ The first load current I ₁ input to the overcurrent relay with voltage suppression 50 ₁ is a vector difference between the R-phase load current I _R and the S-phase load current I _S, and the first load current I ₁ The amplitude is 3 ^1/2 times the amplitude of the R-phase load current I _R (S-phase load current I _S ).
I ₁ = I _R −I _S
| I ₁ | = | I _R −I _S | = 3 ^1/2 × | I _R | = 3 ^1/2 × | I _S |
Thus, since the amplitude of the first load current I ₁ is 3 ^1/2 times the amplitude of the R-phase load current I _R (S-phase load current I _S ), the first overcurrent with voltage suppression is provided. The relay 50 ₁ calculates the _first corrected load current I ₁ ′ by multiplying the first load current I ₁ by 1/3 ^{1/2 as} shown by the following equation.
_{I 1 '= I 1/3} 1/2
| I ₁ '| = | I ₁ | / 3 ^1/2 = | I _R | = | I _S |
Similarly, flow through the load current I _R and T phases of the load current I _T and the second cross through current transformer 10 _{and second} annular core with a phase difference of 120 ° in the R-phase as shown in FIG. 7 Therefore, the second load current I ₂ input from the second cross-through current transformer 10 ₂ to the second overcurrent relay 50 ₂ with voltage suppression is the R-phase load current I _R and the T-phase load current. It becomes a vector difference from I _T, and the amplitude of the _second load current I ₂ is 3 ^1/2 times the amplitude of the R-phase load current I _R (T-phase load current I _T ).
I ₂ = I _R −I _T
| I ₂ | = | I _R −I _T | = 3 ^1/2 × | I _R | = 3 ^1/2 × | I _T |
Thus, since the amplitude of the second load current I ₂ is 3 ^1/2 times the amplitude of the R-phase load current I _R (T-phase load current I _T ), the second overcurrent with voltage suppression is applied. The relay 50 ₂ calculates the _second corrected load current I ₂ ′ by multiplying the second load current I ₂ by 1/3 ^{1/2 as} shown by the following equation.
_{I 2 '= I 2/3} 1/2
| I ₂ '| = | I ₂ | / 3 ^1/2 = | I _R | = | I _T |

The first and second overcurrent relays with voltage suppression 50 ₁ , 50 ₂ determine the occurrence of a short circuit accident and the accident aspect using any one of the first to fifth accident aspect determination methods described above.
Further, when the first and second overcurrent relays with voltage suppression 50 ₁ , 50 ₂ determine that a short-circuit accident has occurred, the first and second overcurrent relays 50 ₁ , 50 ₂ according to the determination result of the accident aspect as follows. correction circuit current I _Ry1 ', I _Ry2' is calculated respectively.

In the case of a short-circuit accident between R phase and S phase When a short circuit accident between R phase and S phase occurs, the short circuit current I _FR of the R phase is internally directed to the R phase of the transmission and distribution line as shown by the dashed arrows in FIG. The S-phase short-circuit current I _FS flows to the outside in the S-phase of the transmission and distribution line, but the T-phase short-circuit current I _FT does not flow in the T-phase of the transmission and distribution line.
Therefore, the first short-circuit current I _Ry1 input from the first cross-through current transformer 10 ₁ to the first overcurrent relay 50 ₁ with voltage suppression is the R phase as shown by the solid line in FIG. Vector short-circuit current I _FR and S-phase short-circuit current I _FS, and the amplitude of the first short-circuit current I _Ry1 is twice the amplitude of the R-phase short-circuit current I _FR (S-phase short-circuit current I _FS ). (Refer to FIG. 8 (a). In FIG. 8, the short-circuit currents I _FR , I _FS , and I _FT flowing in the internal direction of the transmission and distribution lines are solid arrows, and the short circuit flows in the external direction of the transmission and distribution line. The currents I _FR , I _FS , and I _FT are indicated by alternate long and short dashed arrows.)
I _Ry1 = I _FR -I _FS
| I _Ry1 | = | I _FR −I _FS | = 2 × | I _FR | = 2 × | I _FS |
Thus, since the amplitude of the first short-circuit current I _Ry1 is twice the amplitude of the R-phase short-circuit current I _FR (S-phase short-circuit current I _FS ), the first overcurrent relay with voltage suppression 50 ₁ As shown in the following equation, the first corrected short-circuit current I _Ry1 ′ is calculated by multiplying the first short-circuit current I _Ry1 by ½.
I _Ry1 '= I _Ry1 / 2
| I _Ry1 '| = | I _Ry1 | / 2 = | I _FR | = | I _FS |
Further, the second short-circuit current I _Ry2 input from the second cross-through current transformer 10 ₂ to the second overcurrent relay 50 ₂ with voltage suppression is the R-phase as shown by the broken line in FIG. short-circuit current I _FR next to the amplitude of the second short-circuit current I _Ry2 is the amplitude of the short-circuit current I _FR of R-phase (see FIG. 8 (a)).
I _Ry2 = I _FR
｜ I _Ry2 ｜ ＝ ｜ I _FR ｜
Thus, since the amplitude of the second short-circuit current I _Ry2 becomes the amplitude of the R-phase short-circuit current I _FR , the second overcurrent relay with voltage suppression 50 ₂ has a second short-circuit as shown in the following equation. The current I _Ry2 is multiplied by 1 to calculate a second corrected short-circuit current I _Ry2 ′.
I _Ry2 '＝ I _Ry2
| I _Ry2 '| = | I _Ry2 | = | I _FR |
(2) In the case of a short-circuit accident between the S phase and the T phase When a short circuit accident between the S phase and the T phase occurs, the S phase short circuit current I _FS flows in the S phase of the transmission and distribution line in the internal direction, and the T of the transmission and distribution line Although the T-phase short-circuit current I _FT flows in the external direction in the phase, the R-phase short-circuit current I _FR does not flow in the R-phase of the transmission and distribution line.
Accordingly, the first short-circuit current I _Ry1 input from the first cross-through current transformer 10 ₁ to the first overcurrent relay 50 ₁ with voltage suppression is the S-phase short-circuit current −I _FS having a negative polarity. The amplitude of the first short-circuit current I _{Ry1 is} the amplitude of the S-phase short-circuit current I _FS (see FIG. 8B).
I _Ry1 = −I _FS
| I _Ry1 | = | I _FS |
Thus, since the amplitude of the first short-circuit current I _{Ry1 is} the amplitude of the S-phase short-circuit current I _FS , the first overcurrent relay with voltage suppression 50 ₁ has the first short-circuit as shown in the following equation. The current I _Ry1 is multiplied by 1 to calculate a first corrected short-circuit current I _Ry1 ′.
I _Ry1 '＝ I _Ry1
| I _Ry1 '| = | I _Ry1 | = | I _FS |
Further, the second short-circuit current I _Ry2 input from the second cross-through current transformer 10 ₂ to the second overcurrent relay with voltage suppression 50 ₂ becomes a T-phase short-circuit current −I _FT having a negative polarity. The amplitude of the second short-circuit current I _{Ry2 is} the amplitude of the T-phase short-circuit current I _FT (see FIG. 8B).
I _Ry2 = −I _FT
| I _Ry2 | = | I _FT |
Thus, since the amplitude of the second short-circuit current I _Ry2 becomes the amplitude of the T-phase short-circuit current I _FT , the second overcurrent relay with voltage suppression 50 ₂ has a second short-circuit as shown in the following equation. The current I _Ry2 is multiplied by 1 to calculate a second corrected short-circuit current I _Ry2 ′.
I _Ry2 '＝ I _Ry2
| I _Ry2 '| = | I _Ry2 | = | 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, a T phase short circuit current I _FT flows in the T phase of the transmission and distribution line, and the R of the transmission and distribution line. While the short-circuit current I _FR of R-phase to phase flows 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.
Accordingly, the first short-circuit current I _Ry1 input from the first cross-through current transformer 10 ₁ to the first overcurrent relay 50 ₁ with voltage suppression becomes the R-phase short-circuit current I _FR , and the first short circuit The amplitude of the current I _{Ry1 is} the amplitude of the R-phase short-circuit current I _FR (see FIG. 8C).
I _Ry1 = I _FR
｜ I _Ry1 ｜ ＝ ｜ I _FR ｜
Thus, since the amplitude of the first short-circuit current I _{Ry1 is} the amplitude of the R-phase short-circuit current I _FR , the first short-circuit overcurrent relay 50 ₁ has the first short-circuit as shown in the following equation. The current I _Ry1 is multiplied by 1 to calculate a first corrected short-circuit current I _Ry1 ′.
I _Ry1 '＝ I _Ry1
| I _Ry1 '| = | I _Ry1 | = | I _FR |
The second short-circuit current I _Ry2 input from the second cross-through current transformer 10 ₂ to the second overcurrent relay with voltage suppression 50 ₂ includes the R-phase short-circuit current I _FR and the T-phase short-circuit current. It becomes a vector difference from I _FT, and the amplitude of the second short-circuit current I _Ry2 is twice the amplitude of the R-phase short-circuit current I _FR (T-phase short-circuit current I _FT ) (see FIG. 8C).
I _Ry2 = I _FR −I _FT
| I _Ry2 | = | I _FR −I _FT | = 2 × | I _FR | = 2 × | I _FT |
Thus, since the amplitude of the second short-circuit current I _Ry2 is twice the amplitude of the R-phase short-circuit current I _FR (T-phase short-circuit current I _FT ), the second overcurrent relay with voltage suppression 50 _{2 is used.} As shown by the following equation, the second corrected short-circuit current I _Ry2 ′ is calculated by multiplying the second short-circuit current I _Ry2 by ½.
I _Ry2 '= I _Ry2 / 2
| I _Ry2 '| = | I _Ry2 | / 2 = | 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, short circuit current I of R phase to R phase, S phase, and T phase of the transmission and distribution line _FR and S-phase short-circuit current I _FS and T-phase short-circuit current I _FT flow in the internal direction with a phase difference of 120 °.
Therefore, the first short-circuit current I _Ry1 input from the first cross-through current transformer 10 ₁ to the first overcurrent relay 50 ₁ with voltage suppression is the R-phase short-circuit current I _FR and the S-phase short-circuit current I. becomes a vector difference between the _FS, the amplitude of the first short-circuit current I _Ry1 is three ^half the amplitude of the short-circuit current I _FR of R-phase (short-circuit current I _FS of S phase) (see FIG. 8 (d) ).
I _Ry1 = I _FR -I _FS
| I _Ry1 | = | I _FR −I _FS | = 3 ^1/2 × | I _FR | = 3 ^1/2 × | I _FS |
Thus, since the amplitude of the first short-circuit current I _Ry1 is 3 ^1/2 times the amplitude of the R-phase short-circuit current I _FR (S-phase short-circuit current I _FS ), the first overcurrent with voltage suppression The relay 50 ₁ calculates the first corrected short-circuit current I _Ry1 ′ by multiplying the first short-circuit current I _Ry1 by 1/3 ^{1/2 as} shown by the following equation.
I _Ry1 '= I _Ry1 / 3 ^1/2
| I _Ry1 '| = | I _Ry1 | / 3 ^1/2 = | I _FR | = | I _FS |
The second short-circuit current I _Ry2 input from the second cross-through current transformer 10 ₂ to the second overcurrent relay 50 ₂ with voltage suppression is an R-phase short-circuit current I _FR and a T-phase short-circuit current I. _This is a vector difference from _FT, and the amplitude of the second short-circuit current I _Ry2 is 3 ^1/2 times the amplitude of the R-phase short-circuit current I _FR (T-phase short-circuit current I _FT ) (see FIG. 8D). ).
I _Ry2 = I _FR −I _FT
| I _Ry2 | = | I _FR −I _FT | = 3 ^1/2 × | I _FR | = 3 ^1/2 × | I _FT |
Thus, the amplitude of the second short-circuit current I _Ry2 is 3 ^1/2 times the amplitude of the R-phase short-circuit current I _FR (T-phase short-circuit current I _FT ). The relay 50 ₂ calculates the second corrected short-circuit current I _Ry2 ′ by multiplying the second short-circuit current I _Ry2 by 1/3 ^{1/2 as} shown by the following equation.
I _Ry2 '= I _Ry2 / 3 ^1/2
| I _Ry2 '| = | I _Ry2 | / 3 ^1/2 = | I _FR | = | I _FT |

When the first and second overcurrent relays with voltage suppression 50 ₁ and 50 ₂ determine that a short-circuit accident has occurred, the suppression voltage V _Ry is set according to the determination result of the accident aspect as described above. calculate.

The first and second overcurrent relays 50 ₁ , 50 ₂ with voltage suppression have current settling values determined by voltage suppression characteristics (see FIG. 5) that define the magnification of the current settling value according to the suppression voltage V _Ry . the first and second correction circuit current I _Ry1 ', I _Ry2' when the amplitude of is exceeded, the batch cut off the first to third circuit breaker 2 ₁ to 2 _3.

In the above description, the first cross through current transformer 10 ₁ second to cross through the current transformer 10 ₂ electric transmission causes penetrate by crossed R phase and the S-phase of the electric transmission on R Although the phase and the T phase are crossed and penetrated, the two phases of the transmission and distribution lines that are crossed and penetrated by the first and second cross through current transformers 10 ₁ and 10 ₂ may be other combinations.

Further, in the fourth accident mode determination method described above, the R-phase phase voltage V _R is 2 in the polarity direction, the S-phase phase voltage V _S is in the opposite polarity direction, and the T-phase phase voltage V _T is 2 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 in the polarity direction and the phase voltage V of the S phase. the _S in the opposite polarity direction, has been connected to the secondary side of the accident aspect determination transformer 120 to combine with double the polarity direction phase voltage V _T of the T-phase, the phase voltage V _R of the R-phase Multiply a in the polar or antipolar direction by a, multiply the S phase voltage V _S by b in the polar or antipolar direction, and multiply the _T phase voltage V _T by c in the polar or antipolar direction The secondary side of the accident mode determination transformer may be connected so as to be combined. 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

In the above, the cross-through current transformer has been described in combination with the overcurrent relay with voltage suppression used in the transmission / distribution line, but the cross-through current transformer is used in a three-phase AC circuit other than the transmission / distribution line. Similar effects can be obtained by combining with an overcurrent relay with voltage suppression.
In addition, any two phases of the three-phase AC circuit are crossed once in the opposite direction through the annular core of the cross-through current transformer, but any two phases of the three-phase AC circuit cross two or more times. Thus, any two phases of the three-phase AC circuit may be wound around the annular core of the cross-through current transformer the same number or different times so as to penetrate the cross-through current transformer.

It is a figure for demonstrating the overcurrent relay apparatus with a voltage suppression by 1st Example of this invention. The load current I input to the overcurrent relay 50 with voltage suppression from the cross-through current transformer 10 shown in FIG. 1 and the voltage suppression from the instrument transformer 6 shown in FIG. FIG. 5 is a diagram for explaining a T-phase-R phase line voltage V _TR and an R-phase phase voltage V _R input to the overcurrent relay 50. The T-phase to R-phase line voltage V _TR and the R-phase phase voltage V _R input to the overcurrent relay 50 with voltage suppression from the instrument transformer 6 shown in FIG. 1 when a short circuit accident occurs will be described. It is a figure for doing. It is a figure for demonstrating the short circuit current _IRY input into the overcurrent relay 50 with a voltage suppression from the cross penetration current transformer 10 shown in FIG. 1 when a short circuit accident generate | occur | produces. It is a figure which shows an example of a voltage suppression characteristic. It is a figure for demonstrating the overcurrent relay apparatus with a voltage suppression by the 2nd Example of this invention. When the short circuit accident does not occur, the first and second cross-through current transformers 10 ₁ and 10 ₂ shown in FIG. 6 are changed from the first and second overcurrent relays 50 ₁ and 50 ₂ with voltage suppression, respectively. first and second load current I is input ₁ is a diagram for explaining I _2. When a short circuit accident occurs, the first and second cross-through current transformers 10 ₁ and 10 ₂ shown in FIG. 6 are input to the first and second overcurrent relays 50 ₁ and 50 ₂ with voltage suppression, respectively. is a diagram for explaining a first and second short-circuit current I _Ry1, I _Ry2 that. It is a figure for demonstrating the conventional method which installs the overcurrent relay with a voltage suppression in each phase of a power transmission and distribution line, and protects from a short circuit accident. It is a figure for demonstrating the conventional method which aims at the protection from a short circuit accident by installing the overcurrent relay with a voltage suppression only in two phases by the transmission / distribution line etc. of a terminal circuit. 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.

Explanation of symbols

1 power 2 ₁ to 2 ₃ first to third circuit breaker 3 ₁ to 3 ₃ first to third current transformer 41 _{to 3} first to third voltage overcurrent relay 6 potential transformers with suppressed 10. Cross-through current transformers 10 ₁ , 10 ₂ First and second cross-through current transformers 50 Overcurrent relays with voltage suppression 50 ₁ , 50 ₂ First and second overcurrent relays with voltage suppression I, I _R , I _S , I _T Load current I ′ Corrected load currents I ₁ , I ₂ First and second load currents I ₁ ′, I ₂ ′ First and second corrected load currents I _Ry , I _FR , I _FS, I _FT short-circuit current I _Ry 'correction circuit current I _Ry1, I _Ry2 first and second short-circuit current I _Ry1', I _Ry2 'first and second correction circuit current V _R, V _S, V _T phase Voltage V _RS , V _ST , V _TR Line voltage V _Ry Suppression voltage V _RS-2T , V _{R-S + 2T} , V _{aR + bS + cT} Composite voltage θ Impedance angle α, β Angle range γ, δ First and Second angle Circumference k1, k2 first to the first and composite voltage angular range lambda ₁ to [lambda] ₈ of the second voltage value K ₁ ~K ₈ first to composite voltage value epsilon ₁ ～Ipushiron ₈ eighth first to eighth second 8 short-circuit current angle range

Claims (4)

An overcurrent relay device with voltage suppression for protecting a three-phase AC circuit from a short circuit accident,
A cross-through current transformer (10; 10 ₁ ) in which an arbitrary two phases of the three-phase AC circuit are crossed in an opposite direction and at an arbitrary angle through an annular core around which a secondary coil is wound;
When a short circuit fault is detected based on the short circuit current (I _Ry ; I _Ry1 ) input from the cross-through current transformer and the voltage information of the three-phase AC circuit, it is installed in each phase of the three-phase AC circuit. An overcurrent relay with voltage suppression (50; 50 ₁ ) that collectively shuts off the _first to _third circuit breakers (2 ₁ to 2 ₃ );
An overcurrent relay device with voltage suppression, comprising: Accident aspect determining means for determining the accident aspect of the short circuit accident of the three-phase AC circuit;
A corrected short-circuit current (I _Ry '; I _Ry1 ') is calculated by multiplying the short-circuit current input from the cross-through current transformer by a predetermined multiple according to the determination result of the accident aspect in the accident aspect determination means. Corrected short-circuit current calculating means;
The overcurrent relay device with voltage suppression according to claim 1, further comprising: The overcurrent relay with voltage suppression is
In accordance with the determination result of the accident aspect in the accident aspect determination means, the suppression voltage (V _Ry ) is calculated using the voltage information of the three-phase AC circuit,
When the amplitude of the calculated corrected short-circuit current exceeds a current set value determined by a voltage suppression characteristic that defines a current set value according to the calculated suppressed voltage, the first to third circuit breakers are collectively connected. Cut off,
The overcurrent relay device with voltage suppression according to claim 2, wherein: One phase of the arbitrary two phases of the three-phase AC circuit and one other phase other than the arbitrary two phases are crossed in an opposite direction and at an arbitrary angle on an annular core around which a secondary coil is wound. Other cross-penetrating current transformer (10 ₂ )
When a short-circuit fault is detected based on another short-circuit current (I _Ry2 ) input from the second cross-through current transformer and voltage information of the three-phase AC circuit, the first to third circuit breakers are Overcurrent relay with other voltage suppression (50 ₂ ) to be cut off at once,
The overcurrent relay device with voltage suppression according to any one of claims 1 to 3, further comprising:

Images