JP2007196837A - Different phase mixture contact detecting relay device for ac feeding circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a different phase power supply mixture contact accident with high speed without unnecessary operation due to voltage drop or voltage loss such as a short circuit/ground fault accident occurring out of the protective section of a high order power supply side or a low order load side of an AC feeding circuit. <P>SOLUTION: The different phase power supply mixture contact detecting relay device takes a sample analog wave form of a plurality of input voltage and input current at a constant period and converts it to a digital value, obtains respective voltage between four sets of different phase power supply from the time series sampling data of a plurality of input voltage, obtains respective bus current value of the different power supply from the time-series sampling data of a plurality of input current, determines the mixture contact accident from the comparison result with a determination value, and carries out a protective shut-off of the AC feeding circuit, when the mixture contact accident is detected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  This invention converts three phases into two phases, takes out two sets of quadrature single-phase power supplies, and detects cross-phase contact in a feed transformer that supplies two sets of different-phase single-phase power supplies to an AC feeder circuit The present invention relates to a heterogeneous contact detection relay device for an AC feeding circuit.

  The AC feeding load is a single-phase load, and the AC feeding system uses a three-phase to two-phase conversion transformer to provide two sets of quadrature phase single-phase power supplies to balance the single-phase load on the three-phase power supply side. Composed. On the other hand, the protection against cross-phase contact in the AC feeder circuit is made by detecting a contact accident between two sets of single-phase power supplies in quadrature phase and opening the power supply system. A conventional heterogeneous mixed fault detection relay device will be described with reference to FIGS.

FIG. 9 is a system diagram of an AC feeder circuit protection system. The AC feeder circuit is provided with a heterogeneous mixture detection protection relay 1. The customer's power is supplied from the power supply facility 2 of the power company and is received by the three-phase power source. The received three-phase power is converted into two single-phase M-set power sources and T-seat power sources orthogonal to each other by the customer's feeding transformer 3 and supplied to the load. The voltages of the two sets of single-phase power supply M-seat and T-seat are the secondary voltages (V _m1 , V _m2 , V _t1 , V _t2 ) divided by the middle point by two instrument transformers 4 and 5, respectively. It is input to the mixed contact detection relay device 1.

FIG. 10 is a steady voltage vector diagram of the received three-phase voltage and two sets of single-phase converted voltages. The receiving transformer primary power receiving three-phase voltage vectors a, b, and c are three-phase balanced voltages V each having a phase of 120 °. Single-phase voltage of transformer secondary M-seat is in phase with three-phase power supply b-c phase and voltage value V _S , and single-phase voltage of transformer secondary T-seat is in phase with three-phase power supply a phase This is the voltage value V _S.

Two sets of single-phase power supply voltages V _S are detected by the secondary voltage (V _m1 , V _m2 , V _t1 , V _t2 ) divided by the midpoint of the instrument transformers 4 and 5 shown in FIG. Input to the relay device 1. The M seat voltage (V _m1 , V _m2 ) and the T seat voltage (V _t1 , V _t2 ) have the same value and are orthogonal to each other. The steady-state voltages (V ₁ , V ₂ , V ₃ , V ₄₎ ) Is a regular quadrilateral outer peripheral hypotenuse voltage having two diagonal M- and T-seat single-phase power sources V _S ), and the values thereof are V _S / √2, respectively.

FIG. 11 is a block diagram of a conventional heterogeneous mixture detection relay device. In FIG. 11, input voltages (V _m1 , V _m2 , V _t1 , V _t2 ) are two sets of single-phase power supply voltages input from the instrument transformers 4, 5 in the protection system diagram shown in FIG. 9. These input voltages are converted into a predetermined value by the input conversion means 61, pass through an analog filter, and then sampled and held by the input sampling means 62 for every electrical angular velocity period of the system frequency. This sample hold value is converted into a digital value by the A / D conversion means 63 every period, and each input voltage data converted into the digital value is stored as time series data for an arbitrary number of sampling times in the data storage means 64, Records are updated every cycle. The amplitude value calculating means 65 calculates the sampling value difference (ΔV ₁ , ΔV ₂ , _... ) Between the simultaneous phase sampling data of the input voltages (V _m1 , V _m2 , V _t1 , V _t2 ) stored in the data storage means. ΔV ₃ , ΔV ₄ ) Time series data is obtained, and the amplitude value calculation using each sampling value difference (ΔV ₁ , ΔV ₂ , ΔV ₃ , ΔV ₄ ) time series data is performed, and the interphase voltage (V ₁ , V ₂ , V ₃ , V ₄ ) are obtained. Each sampling value difference (ΔV ₁ , ΔV ₂ , ΔV ₃ , ΔV ₄ ) time series data for calculating amplitude value of interphase voltage (V ₁ , V ₂ , V ₃ , V ₄ ) is the input voltage ( _{Equation 1} ) using the same period sampling data of (V _m1 , V _m2 , V _t1 , V _t2 ), obtained for each period, and obtained sampling value differences (ΔV ₁ , ΔV ₂ , ΔV ₃ , ΔV ₄ ) The data is recorded and updated as time-series data for an arbitrary number of samplings.

[Equation 1]
Sampling difference ΔV ₁ = Sampling value V _m1 − Sampling value V _t1
Sampling difference ΔV ₂ = sampling value V _t1 + sampling value V _m2
Sampling difference ΔV ₃ = Sampling value V _t2 − Sampling value V _m2
Sampling difference ΔV ₄ = − (sampling value V _m1 + sampling value V _t2 )
The comparison / determination unit 66 performs comparison / determination between the respective out-of-phase voltages (V ₁ , V ₂ , V ₃ , V ₄ ) obtained by the amplitude value calculation unit 65 and the operation detection value V _K stored in advance. When any or a plurality of inter-phase voltages (V ₁ , V ₂ , V ₃ , V ₄ ) is equal to or lower than the operation detection value (V _K ), the failure detection is notified to the output processing means 67. The output processing unit 67 outputs an operation signal of the heterogeneous mixture detection relay device to the outside of the device when the comparison determination unit 66 detects a failure.

  Here, VA1, VA2, VB1, VB2 are the magnitudes of the secondary voltage vectors divided by the middle point of the single-phase power supply, and the angles formed by the adjacent secondary voltages VA1, VB1, VA2, VB2 are φ1, φ2, When φ3 and φ4, the four areas S1, S2, S3, S4 divided by the two diagonals of the quadrilateral formed by the feeding voltage vector, the opposite-side area difference ratios S% 1, S% 2, and their A ratio difference ΔS% is obtained, and when the ratio difference ΔS% is equal to or greater than a predetermined value set in advance, it is determined that a heterogeneous mixture has occurred (see Patent Document 1).

Also, when the magnitude of the secondary voltage divided at the midpoint of one single-phase power supply is VA1, VA2, and the magnitude of the secondary voltage divided at the midpoint of the other single-phase power supply is VB1, VB2. The two sets of scalar product difference ratios v% 1, v% 2 and the ratio difference Δv% are obtained. When the ratio difference Δv% is equal to or larger than a predetermined value, it is determined that the heterogeneous mixture has occurred. (For example, refer to Patent Document 2).
JP 2005-110487 A JP 2005-81975 A

  However, the heterogeneous mixture detection relay device that operates by capturing that the quadrilateral outer peripheral voltage is lower than a predetermined voltage value has the following problems.

(1) Unnecessary operation due to a short circuit / ground fault outside the protection section occurring in another customer branch system on the power company's three-phase power supply side (system failure on the primary side of the feeder transformer). That is, the single-phase voltage of the secondary second set of the electric transformer is also lowered according to the drop of the power system voltage. For this reason, the outer peripheral voltage of the quadrilateral is remarkably reduced, leading to unnecessary operation. In order to prevent this unnecessary operation, time cooperation with the power source protection device and the host system protection device on the electric power company side is necessary, and the high-speed protection is hindered.

(2) The quadrilateral outer peripheral voltage composed of the secondary single-phase voltage vector of the feeding transformer is lost during normal operation of the power supply, leading to unnecessary operation. In other words, the circuit configuration is complicated because it is necessary to configure a conditional circuit with higher-level equipment and devices such as a switch on the three-phase power supply side and a power supply voltage detection relay device to suppress unnecessary operations.

(3) There is a possibility of unnecessary operation for failures (same power supply short-circuit / ground fault) other than the target detection failure type (cross-phase power supply mixed contact failure). Quadrilateral outer peripheral voltage consisting of two sets of single-phase voltage vectors due to fault current flowing in short circuit / ground fault caused by feeder system, system impedance, voltage drop resulting from fault point impedance, phase change and impedance voltage division May be reduced to the operation region, and in order to prevent this unnecessary operation, time cooperation with the lower system is required, and thus the high speed of protection is hindered.

  The purpose of the present invention is to detect a mixed-phase power supply accident at high speed without causing unnecessary operation due to a voltage drop or voltage loss such as a short circuit, ground fault, power supply release, etc. occurring outside the protection section on the upper power supply side or lower load side. It is possible to obtain a heterogeneous contact detection relay device for an AC feeder circuit that can simplify on-site testing and maintenance inspection.

  The cross-phase contact detection relay device for an AC feeder circuit according to an embodiment of the present invention is a phase-contact of an AC feeder circuit that supplies power by converting three-phase alternating current into two-phase quadrature single-phase power sources. In the heterogeneous contact detection relay device for an AC feeder circuit for detecting AC, a plurality of input voltages and input currents are converted into analog values, and an analog waveform converted by the input conversion means is sampled at a constant cycle. The sample-and-hold means for storing the data, the A / D conversion means for converting the analog value sampled and held at a constant period into a digital value, and the digital conversion value of the A / D conversion means at a predetermined period in the past. Sampling data storage means for storing / updating as arbitrary time series sampling information, and four sets of time series sampling data of a plurality of input voltages stored in the data storage means A voltage measuring means for obtaining each voltage between the phase power supplies, a current measuring means for obtaining a bus current value of each of the different phase power supplies from time-series sampling data of a plurality of input currents stored in the data storage means, and the voltage measuring means An accident detection means for detecting a mixed accident from a comparison result between a voltage value to be calculated and a current value obtained by the current measuring means and a determination value stored in an arbitrary value in advance, and when the accident detection means detects a mixed accident And an output processing means for performing protection interruption of the AC feeder circuit.

  According to the present invention, there is no unnecessary operation due to a voltage drop due to an out-of-protection fault between the upper power supply side and the lower load side, or a voltage loss due to power supply opening, and it is affected by the connection state of the autotransformer of the feeder circuit. Therefore, it is possible to reliably detect a mixed-phase power supply accident at high speed in all operating states of the feeder circuit. Therefore, simplification of on-site testing and maintenance inspection can be realized.

  Embodiments of the present invention will be described below. FIG. 1 is a system diagram in which a heterogeneous mixture detection relay device for an AC feeder circuit according to an embodiment of the present invention is applied to an AC feeder circuit, and FIG. 2 is a block diagram of the heterogeneous mixture detection relay device of the present invention. Show.

In FIG. 1, the received power of the AC feeder circuit is supplied from a power supply facility 2 of a power company with a three-phase power source. The received three-phase power supply is converted into two single-phase M-set power supplies and T-seat power supplies orthogonal to each other by the feed transformer 3 and supplied to the feed circuit. The M seat and T seat power supplies are connected to the autotransformers 8 and 9, respectively, and the neutral point of each autotransformer is connected to the rail. Two sets of single-phase power supplies M and T are respectively connected in series with instrument transformers 4 and 5, and each of the instrument transformers 4 and 5 is divided into two by connecting two in series. The secondary voltages V _m1 , V _m2 , V _t1 , and V _t2 are respectively input to the heterogeneous mixture detection relay device 1. Also, feeding circuit bus current, the secondary current I _m of the measuring current transformer 6, 7, I _t is input to the heterophase incompatible detecting relay device 1.

FIG. 1 shows an example of a mixed contact accident between the M seat voltage V _m1 and the T seat voltage V _t1 . The incompatibility fault current If flows in the loop feedback circuit via the incompatibility fault point between the M seat and the T seat and the midpoint of the autotransformers 8, 9 and the rail. This loop feedback current If is equal in both of the values converted to ½ at the turn ratio (2: 1) between the midpoint and both ends of each autotransformer 8, 9, and each has an opposite phase. flowing through the feeding circuit bus M seat currents I _m and T loci current I _t.

FIG. 2 is a block diagram of the heterogeneous mixture detection relay device according to the embodiment of the present invention. In FIG. 2, V _m1 , V _m2 , V _t1 , and V _t2 are two sets of single-phase power supply voltages input from the instrument transformers 4 and 5. I _m, I _t is different phase power mutual M locus is input from the measuring current transformer 6, a bus current of T locus. These input voltage and input current are respectively converted into predetermined ratios by the input conversion means 21, passed through an analog filter, and then sampled and held by the input sampling and holding means 22 for every electrical angular velocity period of the system frequency. This sample hold value is converted into a digital value by the A / D conversion means 23. The input voltage and input current data converted into digital values are stored and updated as time-series data for the past arbitrary number of cycles in the data storage means 24 every cycle.

The voltage measuring means 25 uses the digital calculation (amplitude value calculation) technique of the input voltage time series data stored in the data storage means 24 for general-purpose public use, and the voltages V ₁ , V ₂ , V ₃ , V ₄ is calculated. Similarly, current measuring means 26 is also stored current data I _m, heterophase power M seat by calculating the amplitude value I _t, T seats respective current I _m, obtains the I _t. Then, an effective part I _mt-P and an ineffective part I _{mt-Q of} the mutual current are calculated. If the electrical angular velocity of the sampling period is 30 °, each amount of electricity can be obtained from the square calculation of the current sampling data and the sampling data 90 ° before.

[Equation 2]
V ₁ = √ {(V _{m1 (n-3)} -V _{t1 (n-3)} ) ² + (V _{m1 (n)} -V _{t1 (n)} ) ² }
V ₂ = √ {(V _{t1 (n-3)} + Vm _{2 (n-3)} ) ² + (V _{t1 (n)} + V _{m2 (n)} ) ² }
V ₃ = √ {(-V _{m2 (n-3)} + V _{t2 (n-3)} ) ² + (-V _{m2 (n)} + V _{t2 (n)} ) ² }
V ₄ = √ {(-V _{t2 (n-3)} -Vm _{1 (n-3)} ) ² + (-V _{t2 (n)} -V _{m1 (n)} ) ² }
[Equation 3]
I _m = √ {(I _{m (n-3)} ) ² + ( _{Im (n)} ) ² }
I _t = √ {(I _{t (n-3)} ) ² + (I _{t (n)} ) ² }
I _mt -P = (I _{m (n)} · I _{t (n)} ) + (I _{m (n-3)} · I _{t (n-3)} )
I _mt-Q = (I _{m (n-3)}・ I _{t (n)} )-(I _{m (n)}・ I _{t (n-3)} )
However, (n-3) is the sampling data before 90 ° at the sampling electrical angular velocity of 30 °, and (n) is the current sampling data.
Further, the current measuring means 26 calculates the current value (Imt- _min ) of the different phase power source, whichever is smaller from the currents of the different phase power sources obtained in the above-described digital calculation formula example [Equation 3], and the opposite phase component ratio of the mutual current. (cos (π-θ)) is calculated, and using the following equation consisting of the product of the calculated smaller current value (Imt _-min ) and the cross-phase component ratio of the mutual current (cos (π-θ)) An antiphase component current I _mt-π is calculated.

[Equation 4]
I _mt-π = Imt _-min・ cos (π-θ) ^k
However, k is a constant determined in advance and is a logarithm that makes the mutual current phase function of the M and T positions low, and suppresses the calculated value of the antiphase component (I _mt-π ) according to the phase difference. Can do.

Next, the accident detection means 27 includes the interphase power supply voltages V ₁ , V ₂ , V ₃ , V ₄ measured by the voltage measurement means 25 and the current measurement means 26, respectively, and the different phase power supplies (M seat, T seat). ) Each of the opposite phase currents I _mt-π is determined in advance and stored in a memory (not shown) using the respective determination constants k _v and k _I. Is detected as an incompatibility failure when a predetermined logical condition [Equation 5] is satisfied.

[V1 comparison judgment] ... 1 when the following formula is satisfied, V ₁ ≤k _v
[V2 comparison judgment] ... 1 when the following formula is satisfied, V ₂ ≤k _v
[V3 comparison judgment] ... 1 when the following equation is satisfied, V ₃ ≤k _v
[V4 comparison judgment] ... 1 when the following formula is satisfied, V ₄ ≤k _v
[ΔI _mt-π comparison determination] ... 1 when the following equation is established, ΔI _mt-π ≧ k _I
[Equation 5]
([V ₁ comparison determination] + [V ₂ comparison determination] + [V ₃ comparison determination] + [V ₄ comparison determination]) × [ΔI _mt-π comparison determination] ≧ 1
As described above, the judgment logic of the accident detection means 27 is based on the voltage drop of the secondary single-phase power supply caused by a short circuit / ground fault outside the protection section occurring in the upper power supply, or in the feeding protection section. Faults other than incompatibility faults (short circuit / ground fault) Even if the voltages V ₁ , V ₂ , V ₃ , V ₄ between the different phase power supplies drop below the comparison judgment value k _v due to the voltage drop, Unnecessary operation is suppressed by comparing and judging the reverse-phase current ratio ΔI _mt-π . This is because the fault current does not flow to the secondary of the feeder transformer in the case of an out-of-section fault such as a host system power supply. Furthermore, since fault currents other than incompatibility faults (short-circuit / ground fault) flow to the fault side of the single-phase dual power supply, both the current value difference and current phase difference between the fault-side current and the healthy load current are large. It is. Finally, the output processing means 28 executes failure detection external output processing when the logical condition shown in [Formula 3] of the accident detection means 27 is satisfied.

Next, an example of a method for detecting the opposite phase current between the different phase power sources in the current measuring means 26 will be described. The current measuring means 26 uses the current of each of the different phase power sources obtained by the digital arithmetic expression [Equation 3] and [Equation 4], and the smaller value (Imt- _min ) of the different phase power source mutual current and the antiphase component ratio. The anti-phase component current (I _mt-π ) is calculated from the product of (cos (π-θ)), and a specific example of calculating the smaller current value (Imt _-min ) of either one of the different phase power supplies [Expression 6] ].

[Equation 6]
Imt _-min = ((I _m + I _t )-(I _m + I _t )) / 2
However, the means for obtaining the currents (I _m , I _t ) between the different-phase power sources is not limited, but it can also be obtained by the above-described digital arithmetic expression example [Equation 3].

  Next, an example of calculating the antiphase component ratio (cos (π−θ)) of the mutual current is shown in [Formula 7].

[Equation 7]
cos (π-θ) =-I _mt-P / √ (I _mt-P ²・ I _mt-Q ² )
However, the means for obtaining the effective component (I _mt-P ) and the ineffective component (I _mt-Q ) of the heterogeneous power supply mutual current is not _limited, but it can also be obtained by the above-described digital arithmetic expression [Formula 3].

Further, it is possible to calculate directly with data storage means 24 to the stored current sampling data I _m, the amplitude value of I _t and the [number 8.

  Further, another example of the calculation of the antiphase component ratio (cos (π−θ)) of the mutual current is shown in [Formula 8].

[Equation 8]
cos (π-θ) = ((I _{m (n)}・ I _{t (n)} ) + (I _{m (n-3)}・ I _{t (n-3)} )) / ((I _{m (n)} ²・I _{t (n)} ² ) + (I _{m (n)} ² · I _{t (n-3)} ² ) + (I _{m (n-3)} ² · I _{t (n)} ² ) + (I _{m (n− 3)} ²・ I _{t (n-3)} ² ))
However, (n) and (n-3) show examples of sampling cycle data at an electrical angular velocity of 30 °. In principle, sampling data with an electrical angular velocity difference of 90 ° may be used.

Next, the smaller value (Imt _-min ) of the different phase power supply mutual current obtained from the above [Equation 6], [Equation 7], and [Equation 8] and the antiphase component ratio (cos (π-θ)) 3 shows the anti-phase component current between the different-phase power sources detected by the above-described [Equation 4], and Fig. 3 is a characteristic diagram for detecting the anti-phase current component between the different-phase power sources. The horizontal axis represents the phase angle (θ) of the different-phase power source mutual current (I _m , I _t ), and the graph shown in Fig. 3 shows the current between the different-phase power source (Im = 6A, It = 8A) and the mutual current level. 6 shows the detection characteristic of the anti-phase component current (I _mt-π ) according to the phase difference (θ = 0 ° to 360 °), as described in [Equation 6]. _mt-π ) is calculated from the product of the current value (Imt _-min ), whichever is smaller, of the different phase power supplies and the square function (k) of the antiphase component ratio (cos (π-θ)) of the mutual current. Multiply the smaller current (I _m ) 6A by the phase angle function ± 1 A value in the closed area is detected.

That is, 0 A or less (6 to −6 A) when the phase difference of the mutual current is ± 90 ° or less, and 0 A or more (0 to 6 A) when the phase difference of the mutual current is ± 90 ° or more. In addition, the detection characteristic of the antiphase component current (I _mt-π ) is the case where the value of the logarithm k that makes the mutual current phase function of [Equation 6] low is not suppressed (k = 0) and suppressed (k = 2). That is, as can be seen from the comparison between the two characteristics, if the value of the square function k of the mutual current phase is increased, the effect of the hyperbolic suppression characteristic corresponding to the increase in the phase difference can be obtained.

Next, the operation according to the failure type will be described using typical failure vector examples shown in FIGS. 4, 5, and 6. FIG. 4 is a vector diagram showing an example of a mutual power supply incompatible fault, FIG. 5 is a vector diagram showing an example of a T-ground fault, and FIG. 6 is a vector diagram showing an example of a T-seat short-circuit fault. The incompatibility failure in FIG. 4 is a short circuit between different power sources orthogonal to each other, and is an incompatibility failure of the different power sources V _t1 and V _m1 shown in FIG. The mixed circuit voltage is twice the outer quadrilateral hypotenuse voltage. Fault voltage (bus voltage) drops to a voltage corresponding to the impedance ratio of from bus to the failed circuit impedance to fault point, incompatible failure hypotenuse voltage V ₁ and opposed oblique sides voltage V ₃ is lowered the failure voltage autotransformer Decreases to a value divided by half at the midpoint.

As shown in FIG. 1, the incompatible fault current flows between different power sources in opposite phases. The vector diagram of FIG. 4, through the fault current I _t flowing through the T locus becomes the M seat fault current I _m in antiphase. However, in the mixed fault detection relay device according to the present invention, the above-described determination formula [Equation 5] detects the failure as the following determination result.

([V ₁ operation] + [V ₃ operation]) × [ΔI _mt-m operation] = 2 ≧ 1
Next, in the vector relationship between different power sources, typical vector examples when one side power source (T seat) fails will be described with reference to FIGS. FIG. 5 is a vector diagram showing an example of a ground fault at the T seat, and FIG. 6 is a vector diagram showing an example of a T seat short-circuit fault. FIG. 7 shows a failure voltage (a drop rate Vf of the bus voltage with respect to the power supply voltage and a phase change angle Δφ) according to a change in the fault impedance in a ground fault and a short-circuit fault of a general feeder circuit. The fault fault voltage vector change graph is based on the fault point resistance change (10Ω to 0Ω) on the horizontal axis of the graph with the fault point of the feeder circuit constant (the power line impedance is fixed when the power supply system) is interposed in the ground fault fault point. It shows the trend of failure voltage drop rate and phase change. On the other hand, the short-circuit fault voltage vector change graph of FIG. 7 (b) shows the fault voltage corresponding to the feeder circuit impedance change (16Ω to 0Ω) from the bus on the horizontal axis of the graph to the fault point while keeping the impedance of the power supply system constant. It shows the trend of the descent rate and phase change. As can be seen from the trend of FIG. 7, the fault voltage (bus voltage) is the impedance ratio and impedance angle between the impedance from the power source to the fault point and the impedance from the bus to the fault point in both cases of ground fault and short circuit fault. There is a corresponding voltage drop and phase change.

FIG. 5 shows a failure vector of the failure point resistance 2Ω in the ground fault of FIG. The fault voltage Vt in FIG. 5 is equivalent to the bus voltage Vf at the fault location in FIG. 7, the fault voltage drops to 47%, and the phase is inclined by about 20 °. FIG. 6 shows a failure vector at an impedance of 3Ω from the bus to the failure point in the short-circuit failure of FIG. Also fault voltage V _t of FIG. 6 is equivalent to a bus voltage V _f failure seat of Figure 7, the fault voltage drops to 52%, the phase is inclined approximately 7 °. In other words, in the case of both a ground fault and a short-circuit fault, in the case of a complete fault (fault impedance ≒ 0Ω, fault voltage = 0) in the immediate vicinity of the bus, the quadrilateral hypotenuse voltages V ₁ , V ₂ , V ₃ , Each V ₄ decreases from 1 / √2 in the steady state to ½. Therefore, the detection of the incompatibility failure in the conventional method is based on the principle that the operation is not caused by a failure other than the incompatibility, so that the voltage is set to a value that is about 5% lower than the value of 1/2 of the rated voltage. Therefore, the conventional method of detecting the decrease in quadrilateral hypotenuse voltages V ₁ , V ₂ , V ₃ , V ₄ is not suitable for detecting incompatibility failure with high sensitivity, and the failure voltage according to the above-mentioned failure circuit impedance angle Including the unbalance rate of the quadrilateral hypotenuse voltage drop due to the slope of the slope, it can be seen that there is a possibility of unnecessary operation due to other faults (electric circuit ground fault, short circuit fault).

On the other hand, in the method for detecting an incompatibility failure according to the present invention, it is possible to suppress an unnecessary operation for a failure other than the intimacy described above by detecting an antiphase current between different power sources. As shown in the vector diagram of an example of the ground fault of the T seat power source in FIG. 5 and the vector diagram of the example of the short circuit fault vector of the T seat power source in FIG. 6, the fault currents I _{t to} I _t of the fault seat (T seat). 'Is flowing in the fault seat (T seat) with a delay phase from the fault voltage V _t according to the fault impedance angle (10 ° -80 °), but does not flow in the healthy seat (M seat). In addition to being less than the load current value on the sound seat side, the phase of the sound seat (M seat) load current (not shown) is approximately in phase with the sound seat (M seat) voltage V _m It is. That is, one side loses power different power each other (ground, short-circuit fault) cross current I _t ~I _t in ', the current phase of I _m becomes 10 ° to 80 ° in the region. Therefore, as described with reference to FIG. 3, the anti-phase current between the power sources is further greatly suppressed by the mutual current phase difference suppression function, and the current value is close to 0 A, so that the detection of the incompatibility failure is suppressed.

Next, the negative phase component current (I _mt-π ) is calculated from the product of the smaller value (Imt _−min ) of the different phase power supply mutual current, the mutual current ratio (Imt-PU), and the phase component ratio (Imt _−θ ). ) Will be described. Current measuring means 26 is the current data I _m stored, heterophase power each other by calculating an amplitude value I _t (M locus, T seat) respective currents I _m, and calculates the I _t, the heterophasic supply mutual currents obtained The antiphase component current (I _mt-π ) is calculated using the principle equation shown in [Equation 9].

[Equation 9]
(I _mt-π ) = k ・ (Imt _-min ) ・ (Imt _-PU ) ・ e ^(-Imt-θ)
However,
(I _mt-π ): _Antiphase component current
(I _mt-min ): The smaller value of the cross-phase power supply mutual current
(Imt _-PU ): Scalar current ratio between different phase power supplies
(Imt _-θ ): Mutual current vector ratio according to the different phase difference of the different phase power supply mutual current
k: Arbitrary suppression factor
e: Natural logarithm (any common logarithm may be used)
Here, the smaller value (Imt _-min ) of the different phase power supply mutual current is obtained by using the above-mentioned [Equation 6], and the difference between the scalar current ratio (Imt _-PU ) between the different phase power supplies and the different phase difference between the different phase power supply mutual currents. The corresponding mutual current vector ratio (Imt _−θ ) is obtained by the following [Equation 10] and [Equation 11]. If the electrical angular velocity of the sampling period is 30 °, the amount of electricity between the different phase power sources can be obtained from the square calculation of the current sampling data (n) and the sampling data (n−3) 90 ° before.

Next, the scalar current ratio (Imt _−PU ) between the different phase power supplies is shown in [ _Equation 10].

[Equation 10]
(Imt _-PU ) = | I _m -I _t | / | I _m + I _t |
I _m = √ {(I _{m (n-3)} ) ² + (I _{m (n)} ) ² }
It = √ {(I _{t (n-3)} ) ² + (I _{t (n)} ) ² }
Further, the mutual current vector ratio (Imt _−θ ) corresponding to the different phase difference of the different phase power supply mutual current is shown in [Equation 11].

[Equation 11]
(Imt _-θ ) = ΣI / ΔI
ΣI = √ {(I _{m (n)} + I _{t (n)} ) ² + (I _{m (n-3)} + I _{t (n-3)} ) ² }
ΔI = √ {(I _{m (n)} -I _{t (n)} ) ² + (I _{m (n-3)} -I _{t (n-3)} ) ² }
Substituting the values of [Equation 6], [Equation 10], and [Equation 11] into the above-described principle equation [Equation 9] for calculating the antiphase component current (Imt-π), the current between the different phase power sources is a function. The antiphase component current (I _mt-π ) calculation formula [Equation 12] is established.

Next, the antiphase component current (I _mt−π ) is shown in [ _Equation 12].

[Equation 12]
I _mt-π = 0.5k ・ ΔI ・ (1- (ΔI / ΣI)) ・ e ^{− (ΣI / ΔI)}
FIG. 8 shows an example of the detection characteristic of the different phase power supply mutual antiphase current using [Equation 12]. The graph shown in FIG. 8 shows the antiphase current I _mt detected according to the five kinds of mutual current ratios (0 to 10 times) of the M and T positions and the phase difference (0 ° to 360 °) of the mutual current. _-π is shown. The horizontal axis is the phase difference (electrical angle) of the different phase power supply mutual current, and the vertical axis is the detected antiphase current, which is the ratio value [PU value] to the smaller value of the mutual current.

Characteristic curves S1 to S5 are current ratios between different-phase power sources, and are ratio values (I _t / I _m ) of T-seat current values to M-seat current values, and characteristic curve S0 is a ratio value (I _t / I _m ). Is 0, the characteristic curve S1 has a ratio value (It / Im) of 1, the characteristic curve S2 has a ratio value (I _t / I _m ) of 2, the characteristic curve S5 has a ratio value (I _t / I _m ) of 5, A curve S10 is a detection characteristic of the antiphase current corresponding to the phase difference of the mutual current in the five ratios having the ratio value (I _t / I _m ) of 10.

  FIG. 8 shows that the antiphase current detection suppression amount increases as the phase difference between the different power source mutual currents increases and the phase difference between the different power source mutual currents approaches the in-phase region. On the other hand, the mutual current values are equal, and the phase difference is the antiphase current detection value 1PU when the phase difference is 180 °, and the detection suppression amount is zero. In other words, it is possible to reliably suppress unnecessary detection for faults other than incompatibility in which the disparity between the different power supply mutual currents increases, such as a ground fault or short-circuit fault on one power supply side between the different power supplies.

Next, the quadrilateral hypotenuse formed by each orthogonal power supply (M seat and T seat) in the case of incompatibility between the different phase power supplies (M seat and T seat) when the autotransformer of the feeder circuit is opened A method for detecting a contact failure from the voltages V ₁ , V ₂ , V ₃ , and V ₄ will be described.

FIG. 9 is a protection system diagram when the autotransformer in the AC feeder circuit is opened, and only the autotransformers 8 and 9 of the different phase power supply mutual (M seat and T seat) are excluded from FIG. Thus, the configuration and operation of the system diagram are the same as in FIG. FIG. 9 shows an example of an incompatibility failure between the T seat V _t1 and the M seat V _m1 . Since the incompatibility fault impedance becomes infinite due to the opening of the M and T winding autotransformers, no incompatible fault current flows between the different phase power supplies. Accordingly, since no drop in the bus voltage and no phase change occur in both the M seat and the T seat, the voltage vector shown in FIG. In other words, the phase power supply voltages V ₁ , V ₂ , V ₃ , and V _{4 on the} outer periphery of the quadrilateral that were formed by the orthogonal diagonal line between the M seat voltage and the T seat voltage at the steady state before the accident are at the top of the contact failure point. It changes to an equilateral triangle with the same potential. When the rated voltage is 1, the quadrilateral voltages V ₁ , V ₂ , V ₃ and V ₄ before the failure are 1 / √2, respectively, and the voltages after the failure are V ₁ = 0 and V ₂ = V ₄ , respectively. = 1, V ₃ = √2 showing a change tendency close to the value. In addition, since the middle point of the M transformer and the T transformer is installed at the same potential, V _t1 and V _m1 have the same value and the same phase, and V _t2 and V _m2 have the same value and the opposite phase. Become. Based on the phenomenon of incompatibility between different-phase power sources (M and T seats) in the open circuit transformer of the feeder circuit described above, if the following method is used, it is determined from the quadrilateral hypotenuse voltage electricity quantity between the phase power sources. A failure can be detected.

The accident detection means 27 includes the values of the inter-phase power supply voltages V ₁ , V ₂ , V ₃ , V ₄ measured by the voltage measurement means 25 and determination constants kUV, kOV stored in a predetermined memory not shown. When the comparison determination result satisfies a predetermined logical condition [Equation 13], it is detected as an incompatibility failure.

[V ₁ decrease comparison judgment] ... 1 when the following equation is established, V ₁ ≤ k _UV
[V ₁ [excess comparison judgment] ... 1 when the following equation is established, V ₁ ≧ k _OV
[V ₂ drop comparison judgment] ... 1 when the following formula is satisfied, V ₂ ≤k _UV
[V ₂ excess comparison judgment] ... 1 when the following formula is satisfied, V ₂ ≧ k _OV
[V ₃ drop comparison judgment] ... 1 when the following formula is satisfied, V ₃ ≤k _UV
[V ₃ excess comparison judgment] ... 1 when the following formula is satisfied, V ₃ ≧ k _OV
[V ₄ drop comparison judgment] ... 1 when the following formula is satisfied, V ₄ ≤k _UV
[V ₄ excess comparison judgment] ... 1 when the following formula is satisfied, V ₄ ≧ k _OV
[Equation 13]
[V ₁ decreases the comparison determination] × [V ₃ exceeds the comparison determination] + [V ₂ decreases comparison determination] × [V ₄ exceeds the comparison determination] + [V ₃ decreases comparison determination] × [V ₁ exceeds the comparison determination] + [V ₄ lowered comparison determination] × [V ₂ exceeds the comparison determination] ≧ 1
Similarly, the quadrilateral hypotenuse formed by each orthogonal seat (M seat and T seat) power supply in the case of incompatibility between the different phase power sources (M seat and T seat) when the autotransformer of the feeder circuit is opened Another embodiment of a method for detecting an incompatibility failure from the voltages V ₁ , V ₂ , V ₃ , and V ₄ will be described. The phenomenon of incompatibility failure between the different phase power sources (M seat and T seat) when the autotransformer of the feeder circuit is opened is the same as in the description of FIGS. 9 and 10 and will not be described in detail.

The voltage measuring means 25 uses the digital calculation (amplitude value calculation) technology disclosed for general purpose to convert the time series data of the stored input voltage to the voltages V ₁ , V ₂ , V ₃ , V ₄ and so on. The difference voltage ratios ΔV _1-2 and ΔV _2-4 on the hypotenuse are measured. If the electrical angular velocity of the sampling period is 30 °, each amount of electricity can be obtained from the square calculation and the ratio calculation shown in [Equation 14] between the current sampling data and the sampling data 90 ° before.

[Formula 14]
V ₁₂ = (V _{m1 (n-3)} −V _{t1 (n-3} ) ² + (V _{m1 (n)} −V _{t1 (n)} ) ²
V ₂₂ = (V _{t1 (n-3)} + V _{m2 (n-3)} ) ² + (V _{t1 (n)} + V _{m2 (n)} ) ²
V ₃₂ = (-V _{m2 (n-3)} + V _{t2 (n-3)} ) ² + (-V _{m2 (n)} + V _{t2 (n)} ) ²
V42 = (-V _{t2 (n-3)} -V _{m1 (n-3)} ) ² + (-V _{t2 (n)} -V _{m1 (n)} ) ²
ΔV _1-2 = (V ₁ −V ₃ ) / (V ₁ + V ₃ )
ΔV _2-4 = (V ₂ −V ₄ ) / (V ₂ + V ₄ )
Next, the accident detection means 27 determines each value of the difference voltage ratios ΔV _1-2 and ΔV _2-4 of the opposite hypotenuse measured by the voltage measurement means 25, and a determination constant kΔ that is stored in a predetermined memory not shown. Comparison comparison with _v is executed, and when each comparison determination result satisfies a predetermined logical condition [Equation 15], it is detected as an incompatibility failure.

[ΔV _1-3 Comparison Judgment] ... 1 when the following equation is established, ΔV _1-3 ≦ kΔ _v
[ΔV _2-4 Comparison Judgment] ... 1 when the following equation is established, ΔV _2-4 ≦ kΔ _v
[Equation 15]
([ΔV _1-3 comparison judgment] + [ΔV _2-4 comparison judgment]) ≧ 1
Similarly, the quadrilateral hypotenuse formed by each orthogonal seat (M seat and T seat) power supply in the case of incompatibility between the different phase power sources (M seat and T seat) when the autotransformer of the feeder circuit is opened Another embodiment of a method for detecting an incompatibility failure from the voltages V ₁ , V ₂ , V ₃ , and V ₄ will be described. The phenomenon of incompatibility failure between the different-phase power sources (M seat and T seat) when the self-winding transformer of the feeder circuit is opened is the same as the explanation of FIGS. 9 and 10, and the details are omitted.

The voltage measurement means 25 uses the digital calculation (amplitude value calculation) technology for the time series data of the stored input voltage, which is disclosed for general use, from the different phase power supply mutual voltages V _t1 , V _t2 , V _m1 , V _m2 to the different power supply mutual. The difference voltage ratios ΔV _{mt% 1} and ΔV _{mt% 2} are measured. If the electrical angular velocity of the sampling period is 30 °, the difference voltage ratio ΔV _mt can be obtained from the square calculation of the amplitude value shown in [Equation 16] using the current sampling data and the sampling data before 90 °.

[Equation 16]
ΔV _{mt% 1} = {√ ((V _{t1 (n-3)} -V _{m1 (n-3)} ) ² + (V _{t1 (n)} -Vm1 (n)) ² -√ ((V _{t2 (n-3 )} -V _{m2 (n-3)} ) ² + (V _{t2 (n)} -V _{m2 (n)} ) ² )} / {√ ((V _{t1 (n-3)} -V _{m1 (n-3)} ) ² + (V _{t1 (n)} -V _{m1 (n)} ) ² ) + √ ((V _{t2 (n-3)} -V _{m2 (n-3)} ) ² + (V _{t2 (n)} -V _{m2 (n)} )) ² )}
ΔV _{mt% 2} = √ ((V _{t1 (n-3)} -V _{m2 (n-3)} ) ² + (V _{t1 (n)} -V _{m2 (n)} ) ² ) -√ ((V _{t2 (n- 3)} -V _{m1 (n-3)} ) ² + (V _{t2 (n)} -V _{m1 (n)} ) ² )} / {√ ((V _{t1 (n-3)} -V _{m2 (n-3)} ) ² + (V _{t1 (n)} -V _{m2 (n)} ) ² ) + √ ((V _{t2 (n-3)} -V _{m1 (n-3)} ) ² + (V _{t2 (n)} -V _{m1 (n )} )) ² }}
Next, the accident detection means 27 determines the respective measured values of the difference voltage ratios ΔV _{mt% 1} and ΔV _{mt% 2} of the opposite hypotenuse measured by the voltage measurement means 25, and a determination constant kΔ stored in a memory which is predetermined and not shown. Comparison comparison with _v is executed, and when each comparison determination result satisfies a predetermined logical condition [Equation 17], an incompatibility failure is detected.

[ΔV _{mt% 1} comparison judgment] ... 1 (failure detection) when the following equation is established, ΔV _mt% ≧ kΔ _v
[ΔV _{mt% 2} comparison judgment] ... 1 (failure detection) when the following equation is established, ΔV _mt% ≧ kΔ _v
[Equation 17]
([ΔV _{mt% 1} comparison judgment] + [ΔV _{mt% 2} comparison judgment]) ≧ 1
According to the embodiment of the present invention, the connection state of the feeder circuit auto-transformer is reduced without causing unnecessary operation due to a voltage drop due to an out-of-protection fault on the upper power supply side and the lower load side, or a voltage loss due to power supply opening. Without being affected, it is possible to detect a mixed-phase power supply accident at high speed and reliably in all operating states of the feeder circuit, and it is possible to simplify field tests and maintenance inspections.

  Also, when the fault detection condition is the anti-phase component current judgment of the cross-phase power supply mutual current, the voltage drop of the secondary single-phase power supply of the feeder transformer due to a short circuit outside the protection section or a ground fault occurring in the upper power supply Alternatively, it is possible to reliably suppress an unnecessary operation due to a voltage drop caused by a fault (short circuit / ground fault) other than the incompatibility fault that occurs in the feeder protection section, and to reliably detect the target incompatibility fault. This is because high-order power supply failures and feeder short-circuits and ground faults have the effect of expanding the hyperbola suppression characteristics according to the current disparity between the different-phase power sources and the phase difference with respect to the operating phase range, while the mixed-phase failure causes the different-phase power sources. This is because incompatible component currents (anti-phase component currents) flowing mutually are extracted.

  In addition, the mixed current between the different-phase power supplies flows through the middle point of the end-winding transformer single-winding transformer on both power sources of the AC feeder circuit. AC self-winding transformer feed circuit is based on single-turn transformer operation, and in normal operation there is no problem with the above-mentioned failure detection of anti-phase component current judgment, but just before connection of the single-turn transformer at the start of feeding In the case where an incompatibility failure occurs, that is, in the incompatibility failure where the autotransformer is disconnected, the incompatible component current (antiphase component current) does not flow between the different-phase power sources, so the inphase fault current detection method cannot detect the incompatibility failure. Therefore, a color mixing failure can be reliably detected from the ratio of the quadrangle-opposed oblique side voltage or the ratio of the vector voltage difference between the midpoint divided voltages of the different phase power supplies.

The systematic diagram which applied the heterophase mixture detection relay apparatus for alternating current feeders concerning embodiment of this invention to the alternating current feeder circuit. The block block diagram of the heterogeneous mixture detection relay apparatus for alternating current feeding circuits concerning embodiment of this invention. The detection characteristic figure of the anti | reverse | negative phase component electric current between different phase power supplies in the different phase mixing detection relay apparatus for alternating current feeding circuits concerning embodiment of this invention. The vector diagram which shows an example of a power supply mutual incompatibility failure. The vector diagram which shows an example of T ground fault. The vector diagram which shows an example of T seat short circuit failure. The characteristic view which shows an example of a failure voltage fall rate and a phase change. The opposite phase current detection characteristic diagram of different phase power supplies. AC feeder circuit protection system diagram. The steady-state voltage vector figure of the three-phase voltage of an incoming call in an AC feeder circuit, and two sets of single phase conversion voltages. The block block diagram of the conventional mixed contact detection relay apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Interphase detection detection protection relay, 2 ... Power supply equipment, 3 ... Feeding transformer, 4, 5 ... Instrument transformer, 6, 7 ... Measuring current transformer, 8, 9 ... Single volume transformer, 21 ... Input conversion means, 22 ... input sampling hold means, 23 ... A / D conversion means, 24 ... data storage means, 25 ... voltage measurement means, 26 ... current measurement means, 27 ... accident detection means, 28 ... output processing means

Claims (6)

  In a cross-phase mixing detection relay device for an AC feeding circuit that detects a phase mixture of an AC feeding circuit that converts a three-phase alternating current into two sets of quadrature and converts to a single-phase power supply and supplies power, a plurality of input voltages and Input conversion means for converting an input current into an analog value, sample hold means for sampling and storing the analog waveform converted by the input conversion means at a constant cycle, and an analog value sampled and held at a constant cycle A / D conversion means for converting to a digital value, sampling data storage means for storing / updating digital conversion values of the A / D conversion means as past arbitrary time series sampling information at regular intervals, and the data storage means Voltage measuring means for obtaining voltages between four sets of different phase power supplies from time-series sampling data of a plurality of input voltages stored therein; Current measurement means for obtaining the bus current value of each of the different phase power supplies from the time-series sampling data of the plurality of input currents stored in the means, the voltage value obtained by the voltage measurement means, the current value obtained by the current measurement means, and an arbitrary value in advance Accident detection means for detecting a contact accident from a comparison result with a determination value to be determined and stored, and an output processing means for executing protection interruption of the AC feeder circuit when the accident detection means detects a contact accident What is provided is a heterogeneous contact detection relay device for an AC feeder circuit.   2. The AC feeding circuit according to claim 1, wherein the current measuring unit calculates an antiphase component current using a phase difference between a smaller one of the different phase power supply mutual currents and the different phase power supply mutual current. Heterogeneous contact detection relay device.   2. The current measuring unit calculates an antiphase component current using a current which is smaller of the different phase power supply mutual current, a scalar current ratio of the different phase power supply mutual current, and a vector current ratio. Heterogeneous contact detection relay device for AC feeder circuits.   2. The accident detection means detects an incompatibility accident based on a combination of a voltage drop and an excess voltage of a quadrilateral of four sides of a quadrilateral formed on a diagonal line with respect to a different-phase power supply mutual voltage calculated by the voltage measurement means. -Phase mixed contact detection relay device for AC feeding circuit.   2. The heterophase for an AC feeder circuit according to claim 1, wherein the accident detection means detects an incompatibility accident based on a difference voltage ratio value of opposite hypotenuse voltages of a quadrilateral and four hypotenuses formed on a diagonal line. Contact detection relay device.   2. The AC feeder circuit according to claim 1, wherein the accident detection means calculates a ratio value of vector differences between voltages divided at the respective midpoints of the different-phase power sources, and detects a mixed accident from the ratio value. Heterogeneous contact detection relay device.

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