JP2011091910A - Disconnection protective relay system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disconnection protective relay system capable of reducing the number of transformers for gauge or current transformers and protecting a three-phase AC circuit from a disconnection failure without deteriorating detection sensitivity even if unbalance occurs between currents of each of phases. <P>SOLUTION: The relay system includes: a cross through current transformer 21 for detecting a composite current I<SB>Ry</SB>formed by compositing an R-phase current I<SB>R</SB>and an S-phase current I<SB>S</SB>; a transformer 2 for gauge for detecting a TR line voltage V<SB>TR</SB>; and a disconnection protective relay device 10 for determining the disconnection failure on the basis of the amount or rate of change of the composite current I<SB>Ry</SB>input from the cross through current transformer 21 and a phase change angle and the amount or rate of change of the TR line voltage V<SB>TR</SB>input from the transformer 2 for gauge and a phase change angle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a disconnection protection relay system, and more particularly, to a disconnection protection relay system suitable for protecting a three-phase AC circuit from a disconnection accident.

Conventionally, in order to protect a three-phase transmission / distribution line (one of three-phase AC circuits) from a disconnection accident, as shown in FIG. 14 (a), a power receiving end (hereinafter referred to as "B end") of the transmission / distribution line The undervoltage relay 111 (voltage relay) is installed on the side, and the R-phase, S-phase, and T-phase voltages V _R , V _S , and V _T are insufficient from the instrument transformer 2 installed on the B-end bus. When input to the voltage relay 111 and one or two of the R-phase, S-phase and T-phase voltages V _R , V _S , V _T are below the voltage set value, the undervoltage relay 111 determines that a disconnection accident has occurred and R-phase distribution line by outputting a trip signal S _T to the first to third circuit breaker 41 _{to 3} of which are respectively installed on the B-end side of the S-phase and T-phase, the first to third The circuit breakers 4 ₁ to 4 ₃ are collectively shut off.

In addition, as shown in FIG. 14 (b), a current relay 112 (current relay) is installed on the B-end side of the transmission / distribution line, and at the B-end side of the R-phase, S-phase, and T-phase of the transmission / distribution line, respectively. From the _first to _third current transformers 3 ₁ to ₃ 3 installed (for the sake of simplicity, the current transformation ratio is 1: 1), the R-phase, S-phase, and T-phase currents I _R and I _S , I _T are input to the current relay 112, and when one or two of the R-phase, S-phase, and T-phase currents I _R , I _S , I _T become less than the current set value, the current relay 112 is determined to be a disconnection accident. by outputting a trip signal S _T to the first to third circuit breaker 41 _{to 3} and, and the first to third circuit breaker 41 _{to 3} to collectively cut off.

Further, the reverse phase current I ₂ (or zero phase current I ₀ ) generated at the time of the disconnection accident is detected, and it is determined that the disconnection accident occurs when all of the following three determination conditions a _{1 to} a ₃ are satisfied. Yes.
[Determination condition a ₁ ] The reverse phase current I ₂ is k times or more (k (reverse phase current detection sensitivity) = 10 to 20%) of the positive phase current I ₁ (generation of the reverse phase current).
The positive phase current I ₁ and the negative phase current I ₂ are calculated by the equations (1) and (2).
I ₁ = (I _R + aI _S + a ² I _T ) / 3 (1)
I ₂ = (I _R + a ² I _S + aI _T ) / 3 (2)
Here, a (vector operator) = − ^1/2 + j × 3 ^1/2 / 2
[Judgment condition a ₂ ] The load current of one or two phases out of the three phases is less than the minimum load current I _min (loss of load current in the accident phase).
[Judgment condition a ₃ ] The remaining two-phase or one-phase load current of the three phases is _{equal to} or greater than the minimum load current I _min (presence of a healthy phase).

In Patent Document 1 below, the three-phase current of the power system is protected and relayed in order to reliably determine a one-phase disconnection regardless of load current fluctuations or current transformer differences in the digital protection relay device. The three-phase current input to the device via a current transformer, sampled through the analog input section, and digitized into a digital processing quantity is led to the arithmetic processing section to calculate the zero-phase current I ₀ , the positive-phase current I ₁ and the negative-phase current I ₂ Thus, there is disclosed a constant monitoring method in which the following formulas are satisfied and a one-phase disconnection is determined for a predetermined time.
3I ₀ / (3T ₁ + K ₀ )> K ₁ I ₁ > K ₂
3T ₀ / 3I ₁ > K ₃
Here, K ₁ and K ₃ = zero phase / positive phase set value.
K ₀ = positive phase offset amount corresponding to the analog input section error.
K ₂ = Positive phase current setting value including error in the analog input section.

JP-A-7-107653

However, in the disconnection protection method using the conventional voltage relay or current relay, the instrument transformer and voltage relay (instrument transformer 2 and undervoltage relay 111) or the current transformer and current relay (first to third transformers). There was a problem that the flow currents 3 _{1 to} 3 ₃ and the current relay 112) were required for three phases.
In addition, in the disconnection protection method using the reverse phase current I ₂ (zero phase current I ₀ ) generated in the event of a disconnection accident, in addition to the problem that three phases are required for the current transformer, In the case of equilibrium, there is no particular problem even if the negative phase current detection sensitivity k is increased. However, if there is an unbalance in each phase current of the transmission / distribution line, malfunction may occur due to the negative phase current I ₂ generated during normal operation. Therefore, there is a problem in that the reverse phase current detection sensitivity k cannot be increased.

  An object of the present invention is to reduce the number of instrument transformers and current transformers, and to protect a three-phase AC circuit from a disconnection accident without degrading detection sensitivity even if each phase current is unbalanced. An object of the present invention is to provide a disconnection protection relay system that can perform this.

The disconnection protection relay system of the present invention is a disconnection protection relay system for protecting a three-phase AC circuit from a disconnection accident, wherein the first to third phases of the three-phase AC circuit respectively flow through the first to third phases. _Combined current detection means (3 ₁ , 3) for detecting a combined current (I _Ry ) obtained by combining the first and second phase currents of the third phase currents (I _R , I _S , I _T ). ₂ ; 21; 22; 23) and a voltage transformer (2) for detecting one line voltage of the three-phase AC circuit or a composite voltage of the three phase voltages of the three-phase AC circuit Voltage synthesis transformer (51; 52), and the synthesized current inputted from the synthesized current detecting means and the one line voltage inputted from the instrument transformer or the voltage synthesized transformer. Disconnection protection relay to determine disconnection accident based on the combined voltage And a device (10).
Here, the disconnection protection relay device performs a disconnection accident based on the change amount or change rate and phase change angle of the combined current and the change amount or change rate and phase change angle of the line voltage or the combined voltage. You may judge.
The combined current detecting means includes a cross-penetration variable in which the first phase of the three-phase AC circuit is penetrated in the polarity direction and the second phase of the three-phase AC circuit is penetrated in the opposite polarity direction. A current transformer (21), or a current transformer (3 ₁ , 3 ₂ ) installed in the first and second phases of the three-phase AC circuit and connected in a differential manner, or of the three-phase AC circuit A straight through current transformer (22) in which the first and second phases are penetrated in the polar direction, or a sum-connected and installed in the first and second phases of the three-phase AC circuit Current transformer (3 ₁ , 3 ₂ ) or two-phase through current transformer (23) in which the second phase of the three-phase AC circuit is penetrated a different number of times in the same direction as the first phase It may be.
The voltage synthesis transformer is configured such that the phase voltage of the first phase of the three-phase AC circuit is in the polarity direction, and the phase voltage of the second phase of the three-phase AC circuit is in the opposite polarity direction, the three-phase AC A voltage synthesis transformer (51) whose secondary side is connected so as to synthesize the phase voltage of the third phase of the circuit by doubling in the polarity direction, or the first phase of the three-phase AC circuit Double the phase voltage in the polarity direction, the phase voltage in the second phase of the three-phase AC circuit in the opposite polarity direction, and the phase voltage in the third phase of the three-phase AC circuit in the opposite polarity direction. It may be a voltage synthesis transformer (52) whose secondary side is connected so as to be synthesized.

The disconnection protection relay system of the present invention is disconnected based on the combined current input from the combined current detecting means and the one line voltage input from the instrument transformer or the combined voltage input from the voltage combining transformer. In order to determine an accident, the following effects are exhibited.
(1) The number of instrument transformers and current transformers can be reduced.
(2) Since a disconnection fault is determined based on the amount or rate of change of the combined current that is not affected by the unbalanced current of each phase, the disconnection can occur without degrading the detection sensitivity even if each phase current is unbalanced. The three-phase AC circuit can be protected from accidents.

It is a figure which shows the structure of the disconnection protection relay system by 1st Example of this invention. The normal combined current I _Ry ′ output from the cross-through current transformer 21 shown in FIG. 1 and the normal TR line voltage V _TR ′ output from the instrument transformer 2 shown in FIG. It is a vector diagram for doing. It is a block diagram which shows the specific structural example of the disconnection protection relay apparatus 10 shown in FIG. FIG. 2 is a vector diagram for explaining a combined current I _Ry output from a cross-through current transformer 21 shown in FIG. 1 and a TR line voltage V _TR output from an instrument transformer 2 shown in FIG. (A) is a vector diagram at the time of R phase disconnection, (b) is a vector diagram at the time of S phase disconnection, (c) is a vector diagram at the time of T phase disconnection. It is a figure which shows the structure of the voltage synthetic | combination transformer used instead of the voltage transformer 2 shown in FIG. 1, (a) is a figure which shows the structure of the voltage synthetic | combination transformer 51, (b) is a voltage synthesis | combination. 3 is a diagram illustrating a configuration of a transformer 52. FIG. It is a vector diagram for demonstrating synthetic | combination voltage VR _{-S + 2T} output from the voltage synthetic | combination transformer 51 shown to _Fig.5 (a), (a) is a vector diagram at the time of normal, (b) Is a vector diagram at the time of R-phase disconnection, (c) is a vector diagram at the time of S-phase disconnection, and (d) is a vector diagram at the time of T-phase disconnection. FIG. 6 is a vector diagram for explaining the synthesized voltage V _RS-2T output from the voltage synthesis transformer 52 shown in FIG. 5B, (a) is a vector diagram at normal time, and (b) is R It is a vector diagram at the time of phase disconnection, (c) is a vector diagram at the time of S phase disconnection, (d) is a vector diagram at the time of T phase disconnection. It is a figure which shows the structure of the disconnection protection relay system by the 4th Example of this invention. It is a figure which shows the structure of the disconnection protection relay system by the 5th Example of this invention. It is a vector diagram for demonstrating synthetic _{| combination} electric current _IRy output from the straight through current transformer 22 shown in FIG. 9, (a) is a vector diagram at the time of normality, (b) is at the time of R phase disconnection It is a vector diagram, (c) is a vector diagram at the time of S phase disconnection, (d) is a vector diagram at the time of T phase disconnection. It is a figure which shows the structure of the disconnection protection relay system by the 8th Example of this invention. It is a figure which shows the structure of the disconnection protection relay system by the 9th Example of this invention. It is a vector diagram for demonstrating synthetic _{| combination} electric current _IRy output from the two-phase through current transformer 23 shown in FIG. 12, (a) is a vector diagram at the time of normal, (b) is at the time of R phase disconnection (C) is a vector diagram at the time of S-phase disconnection, and (d) is a vector diagram at the time of T-phase disconnection. It is a figure for demonstrating the conventional disconnection protection system, (a) is a figure for demonstrating the disconnection protection system using a voltage relay, (b) is a figure for demonstrating the disconnection protection system using a current relay. It is.

  For the above purpose, the amount or rate of change of the combined current and the phase change angle obtained by synthesizing the first and second phase currents of the first to third phase currents and the line spacing between the second and third phases This is realized by determining the disconnection accident based on the voltage, the line voltage between the third and first phases, or the change amount or rate of change of the combined voltage of the three phase voltages and the phase change angle.

Embodiments of the disconnection protection relay system of the present invention will be described below with reference to the drawings.
In the following explanation,
(1) The phase θ _{R of the} normal R-phase current I _R ′ with the magnitudes of the normal R-phase, S-phase, and T-phase currents I _R ′, I _S ′, I _T ′ as the reference (= 1) 'Is the reference (= 0 °). In addition, the magnitudes of the R-phase, S-phase, and T-phase voltages V _R ′, V _S ′, V _T ′ at normal time are set as a reference (= 1), and the phase of the R-phase voltage V _R ′ at normal time is set as a reference ( = 0 °).
(2) Synthesis current 'refers to the rate of change and the current change rate K _Ry for the resultant current I _Ry phase theta combined current I _Ry during normal _Ry' combined current I _Ry during normal I _Ry phase theta _Ry ' A change amount (phase change angle) with respect to is referred to as a current phase change angle Δθ _Ry . Further, called voltage change rate K _TR rate of change with respect to voltage V _TR 'between normal state TR line TR line voltages V _TR, TR line voltage V _TR of the phase θ between normal state TR line _TR the voltage V variation for 'phase theta _TR of' _TR referred to (phase shift angle) between the voltage phase change angle [Delta] [theta] _TR, the change rate for the composite voltage V _{R-S + 2T} 'during normal composite voltage V _{R-S + 2T} Voltage change rate K _{R-S + 2T} , phase of composite voltage V _{R-S + 2T} , phase θ _{R-S + 2T} , phase of normal composite voltage V _{R-S + 2T} ', phase θ _{R-S + 2T} ' with respect to the change angle referred to the voltage phase change angle [Delta] [theta] _{RS + 2T,} and referred to the rate of change with respect to the composite voltage V _RS-2T 'during normal composite voltage V _RS-2T and the voltage change rate K _RS-2T, the composite voltage the change angle to 'phase theta _RS-2T of' V _RS-2T phase theta combined voltage during normal _RS-2T V _RS-2T is referred to as a voltage phase change angle [Delta] [theta] _RS-2T.

The disconnection protection relay system of the present invention uses a combined current of two phase currents of a three-phase AC circuit as a current element, and a combined voltage of one line voltage or three phase voltages of a three-phase AC circuit as a voltage element. It is characterized by using.
In addition, the disconnection protection relay system of the present invention has a symmetric change in the magnitude and phase of the phase current flowing through the healthy phase at the time of the disconnection accident (the current change amount and the current phase change angle during the fault / normal phase of the healthy phase). The change of the absolute value is the same) and the magnitude of the phase voltage of the healthy phase and the symmetrical change of the phase in the event of a disconnection accident (the absolute value of the voltage change amount and voltage phase change angle at the time of normal phase accident / normal) It is characterized in that it is determined as a disconnection accident by paying attention to a change in which the two are the same.

  When the three-phase AC circuit is a three-phase power transmission / distribution line, in the disconnection protection relay system according to the first embodiment of the present invention, as shown in FIG. Installed on the B-end side.

The disconnection protection relay device 10 operates based on the combined current I _Ry input from the cross through current transformer 21 installed on the B end side of the transmission and distribution line.

Here, the cross-through current transformer 21 is a through-type current transformer in which an R-phase and an S-phase of a transmission / distribution wire 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 and distribution line is penetrated in the polarity direction of the cross through current transformer 21 (the direction from the first opening surface side 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 21 (direction from the second opening surface of the annular core to the first opening surface of the annular core).

Therefore, the normal R-phase current I _R ′ and the normal S-phase current I _S ′ are opposite in direction to the annular core of the cross-through current transformer 21 with a phase difference of 120 ° as shown in FIG. (That is, the normal R-phase current I _R 'flows through the cross-through current transformer 21 in the polarity direction, and the normal S-phase current I _S ' flows through the cross-through current transformer 21). _Therefore, the normal combined current I _Ry ′ input from the cross-through current transformer 21 to the disconnection protection relay device 10 is the normal R phase current I _R ′ and the normal R phase current I _R ′. The vector difference from the S-phase current I _S ′ is obtained, and the magnitude and phase of the combined current I _Ry ′ at normal time are 3 ^1/2 and 330 °.
| I _Ry '| = | I _R ' −I _S '| = 3 ^1/2 × | I _R ' | = 3 ^1/2
θ _Ry '= 330 °

Further, the magnitude and phase of the normal TR phase line voltage V _TR ′ input to the disconnection protection relay device 10 from the instrument transformer 2 are 3 ^1/2 and 210 ° (FIG. 2B). reference).
| V _TR '| = | V _T ' −V _R '| = 3 ^1/2 × | V _R ' | = 3 ^1/2
θ _TR '= 210 °

  As shown in FIG. 2, the disconnection protection relay device 10 includes an input converter 11, an analog input unit 12, a memory 13, a current change rate / current phase change angle calculation unit 14, and a voltage change rate / voltage phase. A change angle calculation unit 15, a relay calculation processing unit 16, a settling / display unit 17, an input / output unit 18, and an external device interface unit (external device I / F unit) 19 are provided.

The input converter 11 sets the level of the combined current I _Ry input from the cross-through current transformer 21 and the TR line voltage V _TR input from the instrument transformer 2 to a level suitable for processing of the analog input unit 12. Convert. For simplicity of explanation, the current transformation ratio of the cross-through current transformer 21 and the voltage transformation ratio of the instrument transformer 2 are both 1: 1.
The analog input unit 12 includes a band-pass filter, a sampling hold circuit, a multiplexer circuit, and an analog / digital converter, and the analog combined current I _Ry and the TR line voltage V _TR input from the input converter 11 are digitally converted. Conversion into the combined current I _Ry and the TR line voltage V _TR .
The memory 13 is for storing the combined current I _Ry and the TR line voltage V _TR converted into digital data by the analog input unit 12.

Current change rate and current phase change angle calculation unit 14, dividing it by the magnitude of the resultant current I _Ry of one cycle before which is stored the magnitude of the resultant current I _Ry inputted from the analog input unit 12 to the memory 13 Thus, the change rate of the combined current I _Ry is calculated.
Further, the current change rate / current phase change angle calculation unit 14 calculates the phase θ of the combined current I _Ry one cycle before stored in the memory 13 from the phase θ _Ry of the combined current I _Ry input from the analog input unit 12. by pulling the _Ry, it calculates the phase change angle of the combined current I _Ry.

The voltage change rate / voltage phase change angle calculation unit 15 determines the magnitude of the TR line voltage V _TR input from the analog input unit 12 as the magnitude of the TR line voltage V _TR one cycle before stored in the memory 13. By dividing by this, the rate of change of the TR line voltage V _TR is calculated.
Further, the voltage change rate / voltage phase change angle calculation unit 15 calculates the TR line voltage V one cycle before stored in the memory 13 from the phase θ _{TR of the} TR line voltage V _TR input from the analog input unit 12. by subtracting the phase theta _TR of _TR, it calculates the phase change angle TR line voltage V _TR.

The relay arithmetic processing unit 16 has a rate of change and a phase change angle of the combined current I _Ry calculated by the current rate of change / current phase change angle calculator 14 and a TR calculated by the voltage rate of change / voltage phase change angle calculator 15. Based on the rate of change of the line voltage V _TR and the phase change angle, a disconnection accident is determined by performing a disconnection accident determination process, which will be described later, and first to third interruptions installed on the B-end side of the transmission and distribution line vessel 41 _{to 3} to the production of the trip signal S _T for collectively blocking the generated trip signal first to third circuit breaker via the output unit 18 and an external device interface unit 19 S _T 4 ₁ to send to to 4 _3.

  The settling / display unit 17 performs relay settling processing and displays the settling value and the like to the outside.

Next, the current change rate K _Ry , the current phase change angle Δθ _Ry , the voltage change rate K _TR and the voltage phase change angle Δθ _TR when a disconnection accident occurs in the transmission and distribution line will be described with reference to FIG.

(1) R-phase disconnection When a disconnection accident occurs in the R-phase of the transmission and distribution line, the R-phase current I _R becomes 0 as shown in FIG. 4 (a-1), and the S-phase and T-phase flowing through the healthy phase The magnitudes and phases of the currents I _S and I _T change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (1-1) and (1-2), respectively.
| I _Ry | = | I _R −I _S | = | 0−I _S | = | I _T | = 3 ^1/2 / 2 (1-1)
θ _Ry = 270 ° (1-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (1-3) and (1-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = (3 ^1/2 / 2) / 3 ^1/2 = 0.5 (1-3)
Δθ _Ry = θ _Ry −θ _Ry '= 270 ° −330 ° = −60 ° (1-4)
When a disconnection accident occurs in the R phase of the transmission and distribution line, the R phase voltage V _R becomes 0 as shown in FIG. 4 (a-2), and the S phase and T phase voltages V _S and V _{T of the} healthy phase are obtained. The magnitude and phase of the change symmetrically.
As a result, the magnitude and phase of the TR phase line voltage V _TR are expressed by the equations (1-5) and (1-6), respectively.
| V _TR | = | V _T −V _R | = | V _T −0 | = | V _T | = 3 ^1/2 / 2 (1-5)
θ _TR = 270 ° (1-6)
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the equations (1-7) and (1-8), respectively.
K _TR = | V _TR | / | V _TR '| = (3 ^1/2 / 2) / 3 ^1/2 = 0.5 (1-7)
Δθ _TR = θ _TR −θ _TR ′ = 270 ° −210 ° = 60 ° (1-8)

(2) When a disconnection accident S phase of S-phase disconnection during transmission and distribution lines are generated, as shown in FIG. 4 (b-1), S phase current I _S is zero, R-phase and T-phase flowing healthy phase The magnitudes and phases of the currents I _R and I _T change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (2-1) and (2-2), respectively.
| I _Ry | = | I _R −I _S | = | I _R −0 | = | I _R | = 3 ^1/2 / 2 (2-1)
θ _Ry1 = 30 ° (2-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (2-3) and (2-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = (3 ^1/2 / 2) / 3 ^1/2 = 0.5 (2-3)
Δθ _Ry = θ _Ry −θ _Ry '= 30 ° −330 ° = −300 ° = 60 ° (2-4)
Further, when a disconnection accident occurs in the S phase of the transmission / distribution line, as shown in FIG. 4B-2, the S phase voltage V _S becomes 0, and the R phase and T phase voltages V _R , V _{T of the} healthy phase. The magnitude and phase of the change symmetrically.
As a result, the magnitude and phase of the TR phase line voltage V _TR are expressed by the equations (2-5) and (2-6), respectively.
| V _TR | = | V _T −V _R | = 2 × | V _T | = 2 × 3 ^1/2 / 2 = 3 ^1/2 (2-5)
θ _TR = 210 ° (2-6)
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the equations (2-7) and (2-8), respectively.
K _TR = | V _TR | / | V _TR '| = 3 ^1/2 / 3 ^1/2 = 1 (2-7)
Δθ _TR = θ _TR −θ _TR '= 210 ° −210 ° = 0 ° (2-8)

(3) When T phase disconnection accident T-phase disconnection during transmission and distribution lines are generated, as shown in FIG. 4 (c-1), T-phase current I _T is 0, R-phase and S phase flowing healthy phase The magnitudes and phases of the currents I _R and I _S change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (3-1) and (3-2), respectively.
| I _Ry | = | I _R −I _S | = 2 × | I _R | = 2 × 3 ^1/2 / 2 = 3 ^1/2 (3-1)
θ _Ry = 330 ° (3-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (3-3) and (3-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = 3 ^1/2 / 3 ^1/2 = 1 (3-3)
Δθ _Ry = θ _Ry −θ _Ry '= 330 ° −330 ° = 0 ° (3-4)
When a disconnection accident occurs in the T phase of the transmission / distribution line, as shown in FIG. 4C-2, the T phase voltage V _T becomes 0, and the R phase and S phase voltages V _R , V _{S of the} healthy phase. The magnitude and phase of the change symmetrically.
As a result, the magnitude and phase of the TR phase line voltage V _TR are expressed by the equations (3-5) and (3-6), respectively.
| V _TR | = | V _T −V _R | = | 0−V _R | = | V _S | = 3 ^1/2 / 2 (3-5)
θ _TR = 150 ° (3-6)
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by equations (3-7) and (3-8), respectively.
K _TR = | V _TR | / | V _TR '| = (3 ^1/2 / 2) / 3 ^1/2 = 0.5 (3-7)
Δθ _TR = θ _TR −θ _TR ′ = 150 ° −210 ° = −60 ° (3-8)

  Next, the disconnection accident determination processing method in the relay calculation processing unit 16 of the disconnection protection relay device 10 will be described.

The relay arithmetic processing unit 16 gives a tolerance α (= 0.9 to 1.1) of ± 10% for the current change rate K _Ry and the voltage change rate K _TR , and the current phase change angle Δθ _Ry and the voltage phase. The change angle Δθ _TR is given a tolerance β (= −10 ° to 10 °) of ± 10 °, and a broken line is determined as follows.
(1) When 0.45 ≦ K _Ry ≦ 0.55, −70 ° ≦ Δθ _Ry ≦ −50 °, 0.45 ≦ K _TR ≦ 0.55, 50 ° ≦ Δθ _TR ≦ 70 ° It is determined that a disconnection accident has occurred in the R phase of the distribution line.
(2) Delivery when 0.45 ≦ K _Ry ≦ 0.55, 50 ° ≦ Δθ _Ry ≦ 70 °, 0.9 ≦ K _TR ≦ 1.1, −10 ° ≦ Δθ _TR ≦ 10 ° It is determined that a disconnection accident has occurred in the S phase of the wire.
(3) When 0.9 ≦ K _Ry ≦ 1.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.45 ≦ K _TR ≦ 0.55, −70 ° ≦ Δθ _TR ≦ −50 °, It is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

Next, a disconnection protection relay system according to a second embodiment of the present invention will be described with reference to FIG. 5 (a) and FIG.
The disconnection protection relay system according to the present embodiment uses the voltage synthesis transformer 51 shown in FIG. 5A in place of the instrument transformer 2 shown in FIG. Different from protective relay system.

Here, the secondary side of the voltage synthesis transformer 51 synthesizes the R phase voltage V _R by doubling the S phase voltage V _S in the polarity direction, the S phase voltage V _S in the opposite polarity direction, and the T phase voltage V _T in the polarity direction. It is wired like this.

Therefore, the normal composite voltage V _{R-S + 2T} ′ input from the voltage composite transformer 51 to the disconnection protection relay device 10 is the normal R phase voltage V _R ′ and the negative S phase when the polarity is normal. The vector sum of the voltage V _S ′ (= −V _S ′) and the voltage (= 2V _T ′) obtained by doubling the T-phase voltage V _T ′ at normal time, but the normal R-phase, S-phase, and T Since the phase voltages V _R ′, V _S ′, and V _T ′ are out of phase at 120 ° intervals as shown in FIG. _6A , the magnitude of the normal combined voltage V _{R−S + 2T} ′ and The phases are 7 ^1/2 and 289.1 °.
| V _{R−S + 2T} ′ | = | V _R ′ −V _S ′ + 2V _T ′ | = 7 ^1/2
θ _{R-S + 2T} '= 289.1 °

Next, the voltage change rate K _{R−S + 2T} and the voltage phase change angle Δθ _{R−S + 2T} when a disconnection accident occurs in the transmission / distribution line will be described with reference to FIGS. 6 (b) to 6 (d). To do.

(1) During R-phase disconnection When a disconnection accident occurs in the R-phase of the transmission and distribution line, the magnitude and phase of the combined current I _Ry input from the cross-through current transformer 21 to the disconnection protection relay device 10 are as described above (1 -1) and the above formula (1-2), respectively, and the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the above formula (1-3) and the above formula (1-4), respectively. .
When a disconnection accident occurs in the R phase of the transmission / distribution line, the R phase voltage V _R becomes 0 as shown in FIG. 6B, and the S phase and T phase voltages V _S and V _T of the healthy phase are large. The thickness and phase change symmetrically.
As a result, the magnitude and phase of the combined voltage V _{R-S + 2T} are expressed by the equations (4-1) and (4-2), respectively.
| V _{R-S + 2T} | = | V _R −V _S + 2V _T | = | 0−V _S + 2V _T | = | −V _S + 2V _T | = 3 × | V _T | = 3 × 3 ^1/2 / 2 (4-1)
θ _{R-S + 2T} = 270 ° (4-2)
Therefore, the voltage change rate K _{R−S + 2T} and the voltage phase change angle Δθ _{R−S + 2T} are expressed by the equations (4-3) and (4-4), respectively.
K _{R-S + 2T} = | V _{R-S + 2T} | / | V _{R-S + 2T} '| = (3 × 3 ^1/2 / 2) / 7 ^1/2 (≈0.98) (4- 3)
Δθ _{R−S + 2T} = θ _{R−S + 2T} −θ _{R−S + 2T} ′ = 270 ° −289.1 ° = −19.1 ° (4-4)

(2) During S-phase disconnection When a disconnection accident occurs in the S-phase of the transmission and distribution line, the magnitude and phase of the combined current I _Ry are expressed by the above formula (2-1) and the above formula (2-2), respectively. The current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the above formula (2-3) and the above formula (2-4), respectively.
When a disconnection accident occurs in the S phase of the transmission / distribution line, as shown in FIG. 6C, the S phase voltage V _S becomes 0, and the healthy phase R phase and the T phase voltages V _R and V _T are large. The thickness and phase change symmetrically.
As a result, the magnitude and phase of the combined voltage V _{R-S + 2T} are expressed by the equations (5-1) and (5-2), respectively.
| V _{R−S + 2T} | = | V _R −V _S + 2V _T | = | V _R −0 + 2V _T | = | V _R + 2V _T | = | V _T | = 3 ^1/2 / 2 (5-1)
θ _{R-S + 2T} = 210 ° (5-2)
Therefore, the voltage change rate K _{R−S + 2T} and the voltage phase change angle Δθ _{R−S + 2T} are expressed by the equations (5-3) and (5-4), respectively.
K _{R-S + 2T} = | V _{R-S + 2T} | / | V _{R-S + 2T} '| = (3 ^1/2 / 2) / 7 ^1/2 (≈0.33) (5-3)
Δθ _{R−S + 2T} = θ _{R−S + 2T} −θ _{R−S + 2T} ′ = 210 ° −289.1 ° = −79.1 ° (5-4)

(3) At the time of T-phase disconnection When a disconnection accident occurs in the T-phase of the transmission and distribution line, the magnitude and phase of the combined current I _Ry are expressed by the above formula (3-1) and the above formula (3-2), respectively. The current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the above formula (3-3) and the above formula (3-4), respectively.
When a disconnection accident occurs in the T phase of the transmission / distribution line, as shown in FIG. 6D, the T phase voltage V _T becomes 0, and the healthy phase R phase and the S phase voltages V _R and V _S are large. The thickness and phase change symmetrically.
As a result, the magnitude and phase of the combined voltage V _{R-S + 2T} are expressed by the equations (6-1) and (6-2), respectively.
| V _{R−S + 2T} | = | V _R −V _S + 2V _T | = | V _R −V _S +0 | = | V _R −V _S | = 2 × | V _R | = 2 × 3 ^1/2 / 2 = 3 ^1/2 (5-1)
θ _{R-S + 2T} = 330 ° (6-2)
Therefore, the voltage change rate K _{R−S + 2T} and the voltage phase change angle Δθ _{R−S + 2T} are expressed by the equations (6-3) and (6-4), respectively.
K _{R-S + 2T} = | V _{R-S + 2T} | / | V _{R-S + 2T} '| = 3 ^1/2 / 7 ^1/2 (≈0.65) (6-3)
Δθ _{R−S + 2T} = θ _{R−S + 2T} −θ _{R−S + 2T} ′ = 330 ° −289.1 ° = 40.9 ° (6-4)

  Next, the disconnection accident determination processing method in the relay calculation processing unit 16 of the disconnection protection relay device 10 will be described.

The relay arithmetic processing unit 16 gives a tolerance α (= 0.9 to 1.1) of ± 10% for the current change rate K _Ry and the voltage change rate K _{R-S + 2T} , and the current phase change angle Δθ. _With respect to _Ry and voltage phase change angle Δθ _{R−S + 2T} , a tolerance β of ± 10 ° (= −10 ° to 10 °) is given, and a broken line is determined as follows.
(1) 0.45 ≦ K _Ry ≦ 0.55, −70 ° ≦ Δθ _Ry ≦ −50 °, 0.88 ≦ K _{R-S + 2T} ≦ 1.1, −29.1 ° ≦ Δθ _{R-S When + 2T} ≦ −9.1 °, it is determined that a disconnection accident has occurred in the R phase of the transmission and distribution line.
(2) 0.45 ≦ K _Ry ≦ 0.55, 50 ° ≦ Δθ _Ry ≦ 70 °, 0.30 ≦ K _{R−S + 2T} ≦ 0.36, −89.1 ° ≦ Δθ _{R−S + 2T} In the case of ≦ −69.1 °, it is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) 0.9 ≦ K _Ry ≦ 1.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.59 ≦ K _{R-S + 2T} ≦ 0.72, 30.9 ° ≦ Δθ _{R-S + 2T} In the case of ≦ 50.9 °, it is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

Next, a disconnection protection relay system according to a third embodiment of the present invention will be described with reference to FIG. 5B and FIG.
The disconnection protection relay system according to this embodiment uses the voltage synthesis transformer 52 shown in FIG. 5B in place of the instrument transformer 2 shown in FIG. Different from protective relay system.

Here, the secondary side of the voltage synthesis transformer 52 synthesizes the R-phase voltage V _R by doubling the S-phase voltage V _S in the polarity direction, the S-phase voltage V _S in the opposite polarity direction, and the T-phase voltage V _T in the opposite polarity direction. Wired to do so.

Therefore, the normal composite voltage V _RS-2T ′ input from the voltage composite transformer 52 to the disconnection protection relay device 10 is the normal R phase voltage V _R ′ and the negative S phase voltage V normal. It becomes the vector sum of _S ′ (= −V _S ′) and a voltage (= −2V _T ′) that is twice the normal T phase voltage V _T ′ having a negative polarity. the size of the phase and T-phase voltage V _R ', V _S', V _T 'is 7 since the phase as shown in (a) are shifted at intervals of 120 °, the composite voltage V _RS-2T in the normal' And the phase is 7 ^1/2 and 19.1 °.
| V _RS-2T '| = | V _R ' −V _S '-2V _T ' | == 7 ^1/2
θ _RS-2T '= 19.1 °

Next, the voltage change rate K _RS-2T and the voltage phase change angle Δθ _RS-2T when a disconnection accident occurs in the transmission and distribution line will be described with reference to FIGS.

(1) During R-phase disconnection When a disconnection accident occurs in the R-phase of the transmission and distribution line, the magnitude and phase of the combined current I _Ry input from the cross-through current transformer 21 to the disconnection protection relay device 10 are as described above (1 -1) and the above formula (1-2), respectively, and the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the above formula (1-3) and the above formula (1-4), respectively. .
When a disconnection accident occurs in the R phase of the transmission / distribution line, as shown in FIG. 7 (b), the R phase voltage V _R becomes 0, and the S phase and T phase voltages V _S and V _T of the healthy phase are large. The thickness and phase change symmetrically.
As a result, the magnitude and phase of the combined voltage V _RS-2T are expressed by the equations (7-1) and (7-2), respectively.
| V _RS-2T | = | V _R −V _S −2V _T | = | 0−V _S −2V _T | = | −V _S −2V _T | = | V _S | = 3 ^1/2 / 2 (7 -1)
θ _RS-2T = 90 ° (7-2)
Therefore, the voltage change rate K _RS-2T and the voltage phase change angle Δθ _RS-2T are expressed by the equations (7-3) and (7-4), respectively.
K _RS-2T = | V _RS-2T | / | V _RS-2T '| = (3 ^1/2 / 2) / 7 ^1/2 (≈0.33) (7-3)
Δθ _RS-2T = θ _RS-2T −θ _RS-2T '= 90 ° −19.1 ° = 70.9 ° (7-4)

(2) During S-phase disconnection When a disconnection accident occurs in the S-phase of the transmission and distribution line, the magnitude and phase of the combined current I _Ry are expressed by the above formula (2-1) and the above formula (2-2), respectively. The current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the above formula (2-3) and the above formula (2-4), respectively.
Further, when a disconnection accident occurs in the S phase of the transmission / distribution line, as shown in FIG. 7C, the S phase voltage V _S becomes 0, and the R phase and T phase voltages V _R and V _T of the healthy phase are large. The thickness and phase change symmetrically.
As a result, the magnitude and phase of the combined voltage V _RS-2T are expressed by the equations (8-1) and (8-2), respectively.
| V _RS-2T | = | V _R −V _S −2V _T | = | V _R −0−2V _T | = | V _R −2V _T | = 3 × | V _R | = 3 × 3 ^1/2 / 2 (8-1)
θ _RS-2T = 30 ° (8-2)
Therefore, the voltage change rate K _RS-2T and the voltage phase change angle Δθ _RS-2T are expressed by equations (8-3) and (8-4), respectively.
K _RS-2T = | V _RS-2T | / | V _RS-2T '| = (3 × 3 ^1/2 / 2) −7 ^1/2 (≈0.98) (8-3)
Δθ _RS-2T = θ _RS-2T −θ _RS-2T '= 30 ° −19.1 ° = 10.9 ° (8-4)

(3) At the time of T-phase disconnection When a disconnection accident occurs in the T-phase of the transmission and distribution line, the magnitude and phase of the combined current I _Ry are expressed by the above formula (3-1) and the above formula (3-2), respectively. The current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the above formula (3-3) and the above formula (3-4), respectively.
When a disconnection accident occurs in the T phase of the transmission / distribution line, as shown in FIG. 7D, the T phase voltage V _T becomes 0, and the healthy phase R phase and the S phase voltages V _R and V _S are large. The thickness and phase change symmetrically.
As a result, the magnitude and phase of the combined voltage V _RS-2T are expressed by the equations (9-1) and (9-2), respectively.
| V _RS-2T | = | V _R −V _S −2V _T | = | V _R −V _S −0 | = | V _R −V _S | = 2 × | V _R | = 2 × 3 ^1/2 / 2 = 3 ^1/2 (9-1)
θ _RS-2T = 330 ° (9-2)
Therefore, the voltage change rate K _RS-2T and the voltage phase change angle Δθ _RS-2T are expressed by the equations (9-3) and (9-4), respectively.
K _RS-2T = | V _RS-2T | / | V _RS-2T '| ₌₌ 3 ^1/2 / 7 ^1/2 (≈0.65) (9-3)
Δθ _RS-2T = θ _RS-2T −θ _RS-2T '= 330 ° −19.1 ° = 310.9 ° = −49.1 ° (9-4)

  Next, the disconnection accident determination processing method in the relay calculation processing unit 16 of the disconnection protection relay device 10 will be described.

The relay arithmetic processing unit 16 gives a tolerance α (= 0.9 to 1.1) of ± 10% for the current change rate K _Ry and the voltage change rate K _RS-2T , and the current phase change angle Δθ _Ry and The voltage phase change angle Δθ _RS-2T is given a tolerance β (= −10 ° to 10 °) of ± 10 °, and a broken line is determined as follows.
(1) 0.45 ≦ K _Ry ≦ 0.55, −70 ° ≦ Δθ _Ry ≦ −50 °, 0.30 ≦ K _RS-2T ≦ 0.36, 60.9 ° ≦ Δθ _RS-2T ≦ 80. In the case of 9 °, it is determined that a disconnection accident has occurred in the R phase of the transmission and distribution line.
(2) 0.45 ≦ K _Ry ≦ 0.55, 50 ° ≦ Δθ _Ry ≦ 70 °, 0.88 ≦ K _RS-2T ≦ 1.1, 0.9 ° ≦ Δθ _RS-2T ≦ 20.9 ° In the case of, it is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) 0.9 ≦ K _Ry ≦ 1.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.59 ≦ K _RS-2T ≦ 0.72, −59.1 ° ≦ Δθ _RS-2T ≦ −39 In the case of 1 °, it is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

Next, a disconnection protection relay system according to a fourth embodiment of the present invention will be described with reference to FIG.
The disconnection protection relay system according to the present embodiment includes first and second current transformers 3 ₁ and 3 ₂ that are differentially connected as shown in FIG. 8 instead of the cross-through current transformer 21 shown in FIG. It differs from the disconnection protection relay system according to the first embodiment described above in that it is used.

Here, the first and second current transformers 3 ₁ and 3 ₂ are respectively installed in the R phase and the S phase of the transmission and distribution line.
Therefore, the combined current I _Ry input to the disconnection protection relay device 10 from the first and second current transformers 3 ₁ and 3 ₂ connected in a differential manner is the difference between the R phase current I _R and the S phase current I _S. The vector difference is the same as the combined current I _Ry input from the cross through current transformer 21 shown in FIG.
As a result, the same effect as the disconnection protection relay system according to the first embodiment described above can be obtained.

  In the disconnection protection relay system according to the present embodiment, the voltage synthesis transformers 51 and 52 shown in FIGS. 5A and 5B may be used instead of the instrument transformer 2.

Next, a disconnection protection relay system according to a fifth embodiment of the present invention will be described with reference to FIGS.
The disconnection protection relay system according to the present embodiment uses the straight through current transformer 22 shown in FIG. 9 in place of the cross through current transformer 21 shown in FIG. Different from the relay system.

Here, the straight through current transformer 22 is a through current transformer in which the R phase and the S phase of the power transmission and distribution line are straightly penetrated in the same direction through an annular core around which a secondary coil is wound.
That is, both the R phase and the S phase of the power transmission and distribution line are penetrated in the polarity direction of the straight through current transformer 22 (the direction from the first opening surface of the annular core to the second opening surface of the annular core).

Therefore, the normal R-phase current I _R ′ and the normal S-phase current I _S ′ have a phase difference of 120 ° as shown in FIG. _Therefore, the normal combined current I _Ry ′ input to the disconnection protection relay device 10 from the straight through current transformer 22 is the normal R phase current I _R ′ and the normal S phase current I. It becomes a vector sum with _S ′, and the magnitude and phase of the combined current I _{Ry1 in} the normal state are 1 and 60 °.
| I _Ry '| = | I _R ' + I _S '| = 1
θ _Ry '= 60 °

Next, with respect to the current change rate K _Ry , current phase change angle Δθ _Ry , voltage change rate K _TR, and voltage phase change angle Δθ _TR when a disconnection accident occurs in the transmission and distribution line, FIGS. 10 (b) to 10 (d). Will be described with reference to FIG.

(1) During R-phase disconnection When a disconnection accident occurs in the R-phase of the transmission and distribution line, the R-phase current I _R becomes 0 as shown in FIG. 10B, and the S-phase and T-phase currents I flowing through the healthy phase The magnitudes and phases of _S and I _T change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (10-1) and (10-2), respectively.
| I _Ry | = | I _R + I _S | = | 0 + I _S | = | I _S | = 3 ^1/2 / 2 (10-1)
θ _Ry = 90 ° (10-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (10-3) and (10-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = (3 ^1/2 / 2) / 1 = 3 ^1/2 / 2 (≈−0.87) (10-3)
Δθ _Ry = θ _Ry −θ _Ry '= 60 ° -30 ° = 30 ° (10-2)
Further, when a disconnection accident occurs in the R phase of the transmission and distribution line, the magnitude and phase of the TR line voltage V _TR input from the instrument transformer 2 to the disconnection protection relay 10 are the above formula (1-5) and the above Each is represented by the formula (1-6).
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the above equations (1-7) and (1-8), respectively.

(2) When a disconnection accident S phase of S-phase disconnection during transmission and distribution lines are generated, as shown in FIG. 10 (c), S-phase current I _S is zero, through a sound phase R phase and T-phase currents I The magnitudes and phases of _{R 1} and I _T change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (11-1) and (11-2), respectively.
| I _Ry | = | I _R + I _S | = | I _R +0 | = | I _R | = 3 ^1/2 / 2 (11-1)
θ _Ry = 30 ° (11-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (11-3) and (11-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = (3 ^1/2 / 2) / 1 = 3 ^1/2 / 2 (≈0.87) (11-3)
Δθ _Ry = θ _Ry −θ _Ry '= 30 ° −60 ° = −30 ° (11-4)
When a disconnection accident occurs in the S phase of the transmission / distribution line, the magnitude and phase of the TR phase line voltage V _TR are expressed by the above formulas (2-5) and (2-6), respectively.
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the above equations (2-7) and (2-8), respectively.

(3) When T phase disconnection accident T-phase disconnection during transmission and distribution lines are generated, as shown in FIG. 10 (d), T-phase current I _T is 0, through a sound phase R phase and S-phase currents I The magnitudes and phases of _{R 1} and I _S change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (12-1) and (12-2), respectively.
| I _Ry | = | I _R + I _S | = 0 (12-1)
θ _Ry = 60 ° (12-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (12-3) and (12-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = _0/1/1 (12-3)
Δθ _Ry = θ _Ry −θ _Ry '= 60 ° -60 ° = 0 ° (12-4)
When a disconnection accident occurs in the T phase of the transmission / distribution line, the magnitude and phase of the TR phase line voltage V _TR are expressed by the above formulas (3-5) and (3-6), respectively.
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the above expressions (3-7) and (3-8), respectively.

  Next, the disconnection accident determination processing method in the relay calculation processing unit 16 of the disconnection protection relay device 10 will be described.

The relay arithmetic processing unit 16 gives a tolerance α (= 0.9 to 1.1) of ± 10% for the current change rate K _Ry and the voltage change rate K _TR , and the current phase change angle Δθ _Ry and the voltage phase. The change angle Δθ _TR is given a tolerance β (= −10 ° to 10 °) of ± 10 °, and a broken line is determined as follows.
(1) When 0.78 ≦ K _Ry ≦ 0.95, 20 ° ≦ Δθ _Ry ≦ 40 °, 0.45 ≦ K _TR ≦ 0.55, 50 ° ≦ Δθ _TR ≦ 70 ° It is determined that a disconnection accident has occurred in the R phase.
(2) When 0.78 ≦ K _Ry ≦ 0.95, −40 ° ≦ Δθ _Ry ≦ −20 °, 0.9 ≦ K _TR ≦ 1.1, −10 ° ≦ Δθ _TR ≦ 10 °, It is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) When −0.1 ≦ K _Ry ≦ 0.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.45 ≦ K _TR ≦ 0.55, −70 ° ≦ Δθ _TR ≦ −50 ° It is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

Next, a disconnection protection relay system according to a sixth embodiment of the present invention will be described.
The disconnection protection relay system according to the present embodiment is based on the above-described fifth embodiment in that the voltage synthesis transformer 51 shown in FIG. 5A is used instead of the instrument transformer 2 shown in FIG. Different from disconnection protection relay system.

Therefore, in the disconnection protection relay system according to the present embodiment, the relay calculation processing unit 16 of the disconnection protection relay device 10 has a tolerance of ± 10% for the current change rate K _Ry and the voltage change rate K _{R-S + 2T.} With α (= 0.9 to 1.1), the current phase change angle Δθ _Ry and the voltage phase change angle Δθ _{R-S + 2T} have a tolerance of ± 10 ° β (= −10 ° to 10 °) The disconnection line is determined as follows.
(1) 0.78 ≦ K _Ry ≦ 0.95, 20 ° ≦ Δθ _Ry ≦ 40 °, 0.88 ≦ K _{R−S + 2T} ≦ 1.1, −29.1 ° ≦ Δθ _{R−S + 2T} In the case of ≦ −9.1 °, it is determined that a disconnection accident has occurred in the R phase of the transmission and distribution line.
(2) 0.78 ≦ K _Ry ≦ 0.95, −40 ° ≦ Δθ _Ry ≦ −20 °, 0.30 ≦ K _{R-S + 2T} ≦ 0.36, −89.1 ° ≦ Δθ _{R-S When + 2T} ≦ −69.1 °, it is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) −0.1 ≦ K _Ry ≦ 0.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.59 ≦ K _{R-S + 2T} ≦ 0.72, 30.9 ° ≦ Δθ _{R-S + When 2T} ≦ 50.9 °, it is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

Next, a disconnection protection relay system according to a seventh embodiment of the present invention will be described.
The disconnection protection relay system according to this embodiment is based on the fifth embodiment described above in that the voltage synthesis transformer 52 shown in FIG. 5B is used instead of the instrument transformer 2 shown in FIG. Different from disconnection protection relay system.

Therefore, in the disconnection protection relay system according to the present embodiment, the relay calculation processing unit 16 of the disconnection protection relay device 10 has a tolerance α (± 10% for the current change rate K _Ry and the voltage change rate K _RS-2T. = 0.9 to 1.1), and the current phase change angle Δθ _Ry and the voltage phase change angle Δθ _RS-2T have a tolerance β of ± 10 ° (= −10 ° to 10 °). The disconnection line is determined as follows.
(1) 0.78 ≦ K _Ry ≦ 0.95, 20 ° ≦ Δθ _Ry ≦ 40 °, 0.30 ≦ K _RS-2T ≦ 0.36, 60.9 ° ≦ Δθ _RS-2T ≦ 80.9 ° In the case of, it is determined that a disconnection accident has occurred in the R phase of the transmission and distribution line.
(2) 0.78 ≦ K _Ry ≦ 0.95, −40 ° ≦ Δθ _Ry ≦ −20 °, 0.88 ≦ K _RS-2T ≦ 1.1, 0.9 ° ≦ Δθ _RS-2T ≦ 20. In the case of 9 °, it is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) −0.1 ≦ K _Ry ≦ 0.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.59 ≦ K _RS-2T ≦ 0.72, −59.1 ° ≦ Δθ _RS-2T ≦ − In the case of 39.1 °, it is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

Next, a disconnection protection relay system according to an eighth embodiment of the present invention will be described with reference to FIG.
The disconnection protection relay system according to this embodiment includes first and second current transformers 3 ₁ and 3 ₂ that are summed as shown in FIG. 11 instead of the straight through current transformer 22 shown in FIG. This is different from the disconnection protection relay system according to the fifth embodiment described above.

Here, the first and second current transformers 3 ₁ and 3 ₂ are respectively installed in the R phase and the S phase of the transmission and distribution line.
Therefore, the combined current I _Ry inputted to the disconnection protection relay device 10 from the first and second current transformers 3 ₁ and 3 ₂ connected in sum is the R-phase current I _R and the S-phase current I _S. The vector sum is obtained, which is the same as the combined current I _Ry input to the disconnection protection relay device 10 from the straight through current transformer 22 shown in FIG.
As a result, the same effect as the disconnection protection relay system according to the fifth embodiment described above can be obtained.

  In the disconnection protection relay system according to the present embodiment, the voltage synthesis transformers 51 and 52 shown in FIGS. 5A and 5B may be used instead of the instrument transformer 2.

Next, a disconnection protection relay system according to a ninth embodiment of the present invention will be described with reference to FIGS.
The disconnection protection relay system according to the present embodiment uses the two-phase through current transformer 23 shown in FIG. 12 in place of the cross through current transformer 21 shown in FIG. Different from protective relay system.

Here, the two-phase through current transformer 23 is a through-type current transformer in which the R phase and the S phase of the transmission / distribution electric wire are penetrated in the same direction through an annular core around which a secondary coil is wound. That is, both the R-phase and S-phase of the transmission / distribution line are penetrated in the polarity direction of the two-phase through current transformer 23 (direction from the first opening surface of the annular core to the second opening surface of the annular core). .
In addition, the R phase of the transmission / distribution line passes through the two-phase through current transformer 23 only once, but the S phase of the transmission / distribution line passes through the two-phase through current transformer 23 twice. As a result, the two-phase through current transformer 23 outputs a sum current of a current flowing through the R phase of the transmission and distribution line and a current that is twice the current flowing through the S phase.

Therefore, the normal R-phase current I _R ′ and the normal S-phase current I _S ′ are polar in the annular core of the two-phase through current transformer 23 with a phase difference of 120 ° as shown in FIG. The normal combined current I _Ry ′ input from the two-phase through current transformer 23 to the disconnection protection relay device 10 is normal R phase current I _R ′ and normal S phase. It becomes a vector sum with a current (= 2I _S ') that is twice the current I _S ', and the magnitude and phase of the combined current I _{Ry1 in} the normal state are 3 ^1/2 and 90 °.
| I _Ry '| = | I _R ' + 2I _S '| = 3 ^1/2
θ _Ry '= 90 °

Next, the current change rate K _Ry , current phase change angle Δθ _Ry , voltage change rate K _TR, and voltage phase change angle Δθ _TR when a disconnection accident occurs in the transmission / distribution line are shown in FIGS. Will be described with reference to FIG.

(1) During R-phase disconnection When a disconnection accident occurs in the R-phase of the transmission and distribution line, the R-phase current I _R becomes 0 as shown in FIG. 13B, and the S-phase and T-phase current I flowing through the healthy phase The magnitudes and phases of _S and I _T change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (13-1) and (13-2), respectively.
| I _Ry | = | I _R + 2I _S | = | 0 + 2I _S | = 2 × | I _S | = 2 × 3 ^1/2 / 2 = 3 ^1/2 (13-1)
θ _Ry = 90 ° (13-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (13-3) and (13-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = 3 ^1/2 / 3 ^1/2 = 1 (13-3)
Δθ _Ry = θ _Ry −θ _Ry '= 90 ° −90 ° = 0 ° (13-4)
Further, when a disconnection accident occurs in the R phase of the transmission and distribution line, the magnitude and phase of the TR line voltage V _TR input from the instrument transformer 2 to the disconnection protection relay 10 are the above formula (1-5) and the above Each is represented by the formula (1-6).
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the above equations (1-7) and (1-8), respectively.

(2) When a disconnection accident S phase of S-phase disconnection during transmission and distribution lines are generated, as shown in FIG. 13 (c), S-phase current I _S is zero, through a sound phase R phase and T-phase currents I The magnitudes and phases of _{R 1} and I _T change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (14-1) and (14-2), respectively.
| I _Ry | = | I _R + 2I _S | = | I _R +0 | = | I _R | = 3 ^1/2 / 2 (14-1)
θ _Ry = 30 ° (14-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (14-3) and (14-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = (3 ^1/2 / 2) / 3 ^1/2 = 0.5 (14-3)
Δθ _Ry = θ _Ry −θ _Ry '= 30 ° −90 ° = −60 ° (14-4)
When a disconnection accident occurs in the S phase of the transmission / distribution line, the magnitude and phase of the TR phase line voltage V _TR are expressed by the above formulas (2-5) and (2-6), respectively.
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the above equations (2-7) and (2-8), respectively.

(3) When T phase disconnection accident T-phase disconnection during transmission and distribution lines are generated, as shown in FIG. 13 (d), T-phase current I _T is 0, through a sound phase R phase and S-phase currents I The magnitudes and phases of _{R 1} and I _S change symmetrically.
As a result, the magnitude and phase of the combined current I _Ry are expressed by the equations (15-1) and (15-2), respectively.
| I _Ry | = | I _R + 2I _S | = | I _S | = 3 ^1/2 / 2 (15-1)
θ _Ry = 150 ° (15-2)
Therefore, the current change rate K _Ry and the current phase change angle Δθ _Ry are expressed by the equations (15-3) and (15-4), respectively.
K _Ry = | I _Ry | / | I _Ry '| = (3 ^1/2 / 2) / 3 ^1/2 = 0.5 (15-3)
Δθ _Ry = θ _Ry −θ _Ry '= 150 ° −90 ° = 60 ° (15-4)
When a disconnection accident occurs in the T phase of the transmission / distribution line, the magnitude and phase of the TR phase line voltage V _TR are expressed by the above formulas (3-5) and (3-6), respectively.
Therefore, the voltage change rate K _TR and the voltage phase change angle Δθ _TR are expressed by the above expressions (3-7) and (3-8), respectively.

  Next, the disconnection accident determination processing method in the relay calculation processing unit 16 of the disconnection protection relay device 10 will be described.

The relay arithmetic processing unit 16 gives a tolerance α (= 0.9 to 1.1) of ± 10% for the current change rate K _Ry and the voltage change rate K _TR , and the current phase change angle Δθ _Ry and the voltage phase. The change angle Δθ _TR is given a tolerance β (= −10 ° to 10 °) of ± 10 °, and a broken line is determined as follows.
(1) When 0.9 ≦ K _Ry ≦ 1.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.45 ≦ K _TR ≦ 0.55, 50 ° ≦ Δθ _TR ≦ 70 ° It is determined that a disconnection accident has occurred in the R phase of the wire.
(2) When 0.45 ≦ K _Ry ≦ 0.55, −70 ° ≦ Δθ _Ry ≦ −50 °, 0.9 ≦ K _TR ≦ 1.1, −10 ° ≦ Δθ _TR ≦ 10 °, It is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) When 0.45 ≦ K _Ry ≦ 0.55, 50 ° ≦ Δθ _Ry ≦ 70 °, 0.45 ≦ K _TR ≦ 0.55, −70 ° ≦ Δθ _TR ≦ −50 °, It is determined that a disconnection accident has occurred in the T phase of the distribution line.

Next, a disconnection protection relay system according to a tenth embodiment of the present invention will be described.
The disconnection protection relay system according to this embodiment is based on the ninth embodiment described above in that the voltage synthesis transformer 51 shown in FIG. 5A is used in place of the instrument transformer 2 shown in FIG. Different from disconnection protection relay system.

Therefore, in the disconnection protection relay system according to the present embodiment, the relay calculation processing unit 16 of the disconnection protection relay device 10 has a tolerance of ± 10% for the current change rate K _Ry and the voltage change rate K _{R-S + 2T.} With α (= 0.9 to 1.1), the current phase change angle Δθ _Ry and the voltage phase change angle Δθ _{R-S + 2T} have a tolerance of ± 10 ° β (= −10 ° to 10 °) The disconnection line is determined as follows.
(1) 0.9 ≦ K _Ry ≦ 1.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.88 ≦ K _{R−S + 2T} ≦ 1.1, −29.1 ° ≦ Δθ _{R−S + When 2T} ≦ −9.1 °, it is determined that a disconnection accident has occurred in the R phase of the transmission and distribution line.
(2) 0.45 ≦ K _Ry ≦ 0.55, −70 ° ≦ Δθ _Ry ≦ −50 °, 0.30 ≦ K _{R-S + 2T} ≦ 0.36, −89.1 ° ≦ Δθ _{R-S When + 2T} ≦ −69.1 °, it is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) 0.45 ≦ K _Ry ≦ 0.55, 50 ° ≦ Δθ _Ry ≦ 70 °, 0.59 ≦ K _{R-S + 2T} ≦ 0.72, 30.9 ° ≦ Δθ _{R-S + 2T} ≦ In the case of 50.9 °, it is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

Next, a disconnection protection relay system according to an eleventh embodiment of the present invention will be described.
The disconnection protection relay system according to the present embodiment is in accordance with the ninth embodiment described above in that the voltage synthesis transformer 52 shown in FIG. 5B is used instead of the instrument transformer 2 shown in FIG. Different from disconnection protection relay system.

Therefore, in the disconnection protection relay system according to the present embodiment, the relay calculation processing unit 16 of the disconnection protection relay device 10 has a tolerance α (± 10% for the current change rate K _Ry and the voltage change rate K _RS-2T. = 0.9 to 1.1), and the current phase change angle Δθ _Ry and the voltage phase change angle Δθ _RS-2T have a tolerance β of ± 10 ° (= −10 ° to 10 °). The disconnection line is determined as follows.
(1) 0.9 ≦ K _Ry ≦ 1.1, −10 ° ≦ Δθ _Ry ≦ 10 °, 0.30 ≦ K _RS-2T ≦ 0.36, 60.9 ° ≦ Δθ _RS-2T ≦ 80.9 In the case of °, it is determined that a disconnection accident has occurred in the R phase of the transmission and distribution line.
(2) 0.45 ≦ K _Ry ≦ 0.55, −70 ° ≦ Δθ _Ry ≦ −50 °, 0.88 ≦ K _RS-2T ≦ 1.1, 0.9 ° ≦ Δθ _RS-2T ≦ 20. In the case of 9 °, it is determined that a disconnection accident has occurred in the S phase of the transmission and distribution line.
(3) 0.45 ≦ K _Ry ≦ 0.55, 50 ° ≦ Δθ _Ry ≦ 70 °, 0.59 ≦ K _RS-2T ≦ 0.72, −59.1 ° ≦ Δθ _RS-2T ≦ −39. In the case of 1 °, it is determined that a disconnection accident has occurred in the T phase of the transmission and distribution line.

In the above, the case where each phase current of the transmission / distribution line is balanced has been described. However, the disconnection protection relay system according to the present invention can prevent a disconnection accident based on a combined current (current element) obtained by combining at least two phase currents. Since it determines, even if there is imbalance in each phase current, a transmission and distribution line can be protected from a disconnection accident.
Further, by setting the tolerance α = 0.9 to 1.1 (± 10%), it is possible to determine up to about ± 20% of the unbalanced current. For example, in the disconnection protection relay system according to the first to fourth embodiments, when the T-phase current I _T has an unbalance rate of 1.2 (+ 20%), the transmission / distribution line is in the R-phase disconnection or the S-phase disconnection. The current change rate K _Ry = 0.55 of the combined current I _Ry at that time, but since the determination condition is 0.45 ≦ K _Ry ≦ 0.55 as described above, it can be determined. In the disconnection protection relay system according to the fifth to eighth embodiments, when the T-phase current I _T has an unbalance rate of 1.2 (+ 20%), the transmission line is in the R-phase disconnection or the S-phase disconnection. Although the current change rate K _Ry = 0.95 of the combined current I _Ry , since the determination condition is 0.78 ≦ K _Ry ≦ 0.95 as described above, it can be determined. In the disconnection protection relay system according to the ninth to eleventh embodiments, when the T-phase current I _T has an unbalance rate of 1.2 (+ 20%), the combined current I _Ry at the R-phase disconnection of the transmission / distribution line is reduced. Although the current change rate K _Ry = 1.1 and the current change rate K _Ry = 0.55 of the combined current I _Ry at the S phase disconnection, as described above, the determination condition at the R phase disconnection is 0.9 ≦ K _{Since Ry} ≦ 1.1 and the determination condition when the S phase is broken is 0.45 ≦ K _Ry ≦ 0.55, determination is possible.
Similarly, by setting the tolerance α = 0.8 to 1.2 (± 20%), it is possible to determine up to about an unbalanced current ± 40%.

Further, although the TR line voltage V _TR is used, the ST line voltage V _ST may be used.

Furthermore, the rate of change of the resultant current I _Ry, rate of change of the TR line voltages V _TR, composite voltage V _{RS + 2T,} is used the rate of change of V _RS-2T, the change amount of the combined current I _Ry (| I _Ry | − | I _Ry '|), the amount of change in TR line voltage V _TR (| V _TR | − | V _TR ' |) and the amount of change in combined voltages V _{R-S + 2T} and V _RS-2T ( | V _{R-S + 2T} | − | V _{R−S + 2T} ′ |, | V _RS−2T | − | V _RS−2T ′ |) may be used.

  Furthermore, you may make it add the function of the disconnection protection relay apparatus 10 to the power transmission line protection relay installed in the B end side of a transmission / distribution electric wire.

DESCRIPTION OF SYMBOLS 1 Power supply 2 Instrument transformer 3 ₁ to ₃ 3 _1st thru | or 3rd current transformer 4 ₁ to 4 _{3 1st} to _3rd circuit breaker 10 Disconnection protection relay apparatus 11 Input converter 12 Analog input part 13 Memory 14 Current Change Rate / Current Phase Change Angle Calculation Unit 15 Voltage Change Rate / Voltage Phase Change Angle Calculation Unit 16 Relay Operation Processing Unit 17 Setting / Display Unit 18 Input / Output Unit 19 External Device Interface Unit (External Device I / F Unit)
21 Cross-through current transformer 22 Straight-through current transformer 23 Two-phase through current transformer 51, 52 Voltage synthesis transformer 111 Undervoltage relay 112 Current relay I _R , I _S , I _T R phase, S phase and T phase current I _R ', I _S ', I _T 'Normal R phase, S phase and T phase currents I _Ry Composite current I _Ry ' Normal composite current I ₀ Zero phase current I ₁ Positive phase current I ₂ Reverse phase current I _min Minimum load current V _R , V _S , V _T R phase, S phase and T phase voltage V _R ', V _S ', V _T 'Normal R phase, S phase and T phase voltage V _TR TR line Voltage V _TR ′ Normal TR line voltage V _{R-S + 2T} , V _RS-2T Composite voltage V _{R-S + 2T} ′, V _RS-2T ′ Normal composite voltage θ _R ′, θ _Ry , θ _{Ry ', θ TR, θ TR} ', θ RS + 2T, θ RS-2T ', θ RS + 2T, θ RS-2T' phase K _Ry current change rate K _TR, K _{RS + 2T} , K _RS-2T voltage change rate Δθ _Ry current phase change angle Δθ _TR , Δθ _{R-S + 2T} , Δθ _RS-2T voltage phase change angle S _T Trip signal a Vector operator k Reverse phase current detection sensitivity α Tolerance

Claims (4)

A disconnection protection relay system for protecting a three-phase AC circuit from a disconnection accident,
A synthesis in which the first and second phase currents of the first to third phase currents (I _R , I _S , I _T ) flowing through the first to third phases of the three-phase AC circuit are synthesized. _Combined current detection means (3 ₁ , 3 ₂ ; 21; 22; 23) for detecting the current (I _Ry );
An instrument transformer (2) for detecting one line voltage of the three-phase AC circuit or a voltage synthesis transformer (51; 52) for detecting a composite voltage of three phase voltages of the three-phase AC circuit )When,
A disconnection accident is determined based on the combined current input from the combined current detecting means and the one line voltage input from the instrument transformer or the combined voltage input from the voltage combining transformer. Disconnection protection relay device (10);
A disconnection protection relay system comprising:   The disconnection protection relay device determines a disconnection accident based on a change amount or change rate and phase change angle of the combined current and a change amount or change rate and phase change angle of the line voltage or the combined voltage. The disconnection protection relay system according to claim 1. The combined current detecting means includes a cross-penetration variable in which the first phase of the three-phase AC circuit is penetrated in the polarity direction and the second phase of the three-phase AC circuit is penetrated in the opposite polarity direction. A current transformer (21), or a current transformer (3 ₁ , 3 ₂ ) installed in the first and second phases of the three-phase AC circuit and connected in a differential manner, or of the three-phase AC circuit A straight through current transformer (22) in which the first and second phases are penetrated in the polar direction, or a sum-connected and installed in the first and second phases of the three-phase AC circuit Current transformer (3 ₁ , 3 ₂ ) or two-phase through current transformer (23) in which the second phase of the three-phase AC circuit is penetrated a different number of times in the same direction as the first phase The disconnection protection relay system according to claim 1 or 2, characterized in that   The voltage synthesis transformer is configured such that the phase voltage of the first phase of the three-phase AC circuit is in the polarity direction, and the phase voltage of the second phase of the three-phase AC circuit is in the opposite polarity direction, the three-phase AC A voltage synthesis transformer (51) whose secondary side is connected so as to synthesize the phase voltage of the third phase of the circuit by doubling in the polarity direction, or the first phase of the three-phase AC circuit Double the phase voltage in the polarity direction, the phase voltage in the second phase of the three-phase AC circuit in the opposite polarity direction, and the phase voltage in the third phase of the three-phase AC circuit in the opposite polarity direction. The disconnection protection relay system according to any one of claims 1 to 3, characterized in that it is a voltage synthesis transformer (52) whose secondary side is connected so as to be combined.