JP2011004455A - Protective relay device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective relay device which automatically protects a power system even if a bus grounding accident occurs when a bus contact breaker is ON and besides a grounding order breaker is not used.SOLUTION: The protective relay device 10 includes trip signal generators 40 and 50 which generate seventh trip signals TRfor breaking the bus contact breaker 4 when the phases of second to sixth zero-phase currents I-Iare all within the range of ±90° to the phase of a first zero-phase current Iin case that both of first and second zero-phase voltages V, Vexceed a zero-phase voltage setting V, generate eighth trip signals TRfor breaking a first power receiving breaker 4in case that only the first zero-phase voltage Vexceeds the zero-phase voltage setting Vafter the bus contact breaker 4 is broken, and generate ninth trip signals TRfor breaking a second power receiving breaker 4in case that only the second zero-phase voltage Vexceeds the zero-phase voltage setting V.

Description

  The present invention relates to a protective relay device, and more particularly to a power system when a bus ground fault occurs when the bus bar breaker is turned on and the ground fault sequence circuit breaker (10G) is not used. The present invention relates to a protective relay device suitable for protecting the device.

Conventionally, as shown in FIG. 9, a second bus connected to the first busbar ₁ and the second secondary side of the transformer 3 ₂ connected to the first secondary side of the transformer 3 ₁ 1 in ₂ and the power system which is connected via a busbar breaker 4 (distribution system 6kV), for example, a first transformer for its repair work failure occurs in the first transformer 3 ₁ 3 _When the connection between the secondary side of 1 and the first bus 1 ₁ is cut off, the _first to _third distribution lines 2 ₁ to 2 ₃ branched from the first bus 1 ₁ are cut off. The power is supplied from the second transformer 3 ₂ to the first bus 1 ₁ via the second bus 1 ₂ with the transformer 4 turned on. At this time, the first and the second distribution lines 2 ₁ to 2 ₆ installed on the secondary side of the first and second transformers 3 ₁ and 3 ₂ and for cutting off the _first to _sixth distribution lines 2 ₁ to 2 ₆ in a predetermined order are provided. And a second ground fault sequence breaker (not shown) is disabled.

When the first and second ground fault sequential circuit breakers are not used in this way, a ground fault (bus ground fault) occurs in either the first or _second bus 1 ₁ or 1 _2. Then, the operator manually shuts off the _first to _sixth distribution lines 2 ₁ to 2 ₆ one line at a time until the ground fault disappears, and then to the primary side of the first or second transformer 3 ₁ , 3 _2. The installed first or second power receiving breaker 4 ₁ , 4 ₂ is manually cut off.

Further, in any of the _first to _sixth distribution lines 21 to ₂₆ , the _first to _sixth ground fault direction relays (DG) installed in the _first to _sixth distribution lines 21 to ₂₆ , respectively. ) Even when a ground fault accident (distribution line ground fault) that does not cause 5 _{1 to} 5 ₆ to operate occurs, the worker sets the _first to _sixth distribution lines 2 ₁ to 2 ₆ to 1 until the ground fault disappears. Each line is manually shut off.

  The following Patent Document 1 discloses a ground fault line selection relay system that selects a ground fault fault line only with a zero phase current regardless of the generation of a zero phase voltage. In this earth fault line selection relay system, the zero-phase current flowing in each line is detected by each zero-phase current transformer, and this is introduced into the comparison judgment circuit, and each zero-phase current value is compared by this comparison judgment circuit. Then, the line with the largest current value is determined to be an accident line, and when the zero-phase current value exceeds the set value, an output is issued and the circuit breaker of the accident line is shut off.

  In Patent Document 2 below, it is possible to recognize a fine ground fault distribution line without interrupting the distribution line breaker (FCB), and to recognize a fine ground fault distribution line according to a power transmission state that has been impossible in the past. In addition, a fine ground fault distribution line recognition device that can quickly and accurately specify a fine ground fault point when the fine ground fault point is between the switches and in the power supply section is disclosed. ing. In this fine ground fault distribution line recognition device, the fine ground fault distribution line recognition unit uses the ground fault voltage of the bank and the ground fault current of each distribution line, determines the current direction from the phase of each fault current, The fine ground fault distribution line is identified from the size and direction of the ground, and in the master station, the ground fault current is determined from the slave station devices installed in each of the switches of the distribution line and the fine ground fault distribution line recognition unit. Collect the maximum value, and for the section between the switches, the maximum value of the ground fault current at the adjacent switch points.For the power section, the maximum value of the ground fault current on the power source side and the ground fault current on the first switch side The maximum value is compared to determine whether there is a ground fault.

  In Patent Document 3 below, each distribution line is trial-opened when a fine ground fault occurs in a distribution substation, and a trial-open operation is possible even when power is exchanged with an auxiliary bus to identify a fine ground fault line. A fine ground fault detection method is disclosed. In this fine ground fault line detection method, a ground fault sequence switch is provided for each distribution line, and the trial opening operation is started depending on whether or not these circuit fault sequence switches are connected to the circuit breaker provided in the auxiliary bus. Change the time from the timing to the trial release timing of the own circuit breaker.

  In the following Patent Document 4, as a suppression amount derivation circuit, the absolute value of the product of the zero-phase voltage and each terminal zero-phase current is obtained by half-cycle integration. Also disclosed is a busbar protection device in which a suppression amount can be obtained.

  In Patent Document 5 below, there is a bus protection relay device configured so that only an input amount of a current differential element is required for a zero-phase current of a circuit through which a relatively large zero-phase current flows when an internal failure occurs in the bus. It is disclosed.

JP-A-9-19047 JP-A-6-113446 JP-A-9-103026 JP-A-3-082333 JP 58-218825 A

However, in order to eliminate the bus ground fault or the distribution line ground fault that has occurred when the first and second ground fault sequence breakers are not used as described above, the worker can remove the first to sixth distribution lines 2 _1. ~ 2 ₆ than or blocked manually cut off or the first or second power receiving breaker 4 ₁ by one line, 4 ₂ manually, it takes a long time to operate.

Further, in the ground fault line selective relay system described in Patent Document 1, a capacitor for flowing a zero-phase current to the bus is necessary.
In the fine ground fault distribution line recognition apparatus described in Patent Document 2, the same method as that of the conventional ground fault direction relay is used to determine the direction of the zero-phase current.
In the fine ground fault detection method described in Patent Document 3, it is necessary to provide a ground fault sequence switch on each distribution line.
In the bus protection device described in Patent Document 4 and the bus protection relay device described in Patent Document 5, it is necessary to install a current differential relay or other relays.

  It is an object of the present invention to provide a zero-phase current flowing through each distribution line and a zero-phase of each bus bar even when a bus ground fault occurs when the bus bar breaker is turned on and the ground fault sequence circuit breaker is not used. An object of the present invention is to provide a protective relay device capable of automatically protecting a power system based on a voltage.

In the protective relay device of the present invention, the first and second power receiving circuit breakers (4 ₁ , 4 ₂ ) are respectively installed on the primary side of the first and second transformers (3 ₁ , 3 ₂ ). Between the first bus (1 ₁ ) connected to the secondary side of the first transformer and the second bus (1 ₂ ) connected to the secondary side of the second transformer. A protective relay device (10) used in a power system having a busbar breaker (4) installed therebetween, wherein the busbar breaker is in an on state, and the first and second The first and second ground fault sequence circuit breakers for cutting off the plurality of distribution lines (2 ₁ to 2 ₆ ) branched from the bus bar in a predetermined order are in the off state, and the first and second when the zero-phase voltage (V _01, V ₀₂₎ exceeds a both zero-phase voltage set value (V _00), said plurality of zero-phase current flowing through the distribution line, respectively (I ₀₁ ~I ₀₆ With the phase of the other zero-phase current when all is within a predetermined angular range, it generates a trip signal for interrupting the busbar breaker (TR ₇₎ to any one of the zero-phase current phase of the A trip signal (TR ₈ ) for shutting off the first power receiving circuit breaker when only the first zero phase voltage exceeds the zero phase voltage settling value after the bus bar breaker is cut off. Trip signal generating means for generating a trip signal (TR ₉ ) for cutting off the second power receiving circuit breaker when only the second zero phase voltage exceeds the zero phase voltage set value. 40, 50).
Here, when the trip signal generating means has all the phases of the other zero-phase currents within a predetermined angle range with respect to the phase of the largest zero-phase current among the zero-phase currents respectively flowing through the plurality of distribution lines. A trip signal (TR ₇ ) for breaking the bus bar breaker may be generated.
The predetermined angle range may be ± 90 °.

The protective relay device of the present invention has the following effects.
(1) By detecting a bus ground fault, based on a comparison between the first and second zero-phase voltages and a zero-phase voltage set value and a phase relationship of zero-phase currents flowing through a plurality of distribution lines, Power is automatically generated based on the zero-phase current flowing through each distribution line and the zero-phase voltage of each bus even if a bus-to-ground fault occurs when the contact breaker is on and the ground fault sequence breaker is not used The system can be protected.
(2) A trip signal for breaking a circuit breaker installed in a distribution line in which the largest zero-phase current among the zero-phase currents flowing through each of the plurality of distribution lines flows is displayed as a zero phase other than the largest zero-phase current. When the current phase is all outside the predetermined angle range with respect to the phase of the largest zero-phase current, the busbar breaker is turned on and the ground fault sequence breaker is not used. A distribution line in which a ground fault has occurred can be shut off automatically.
(3) By considering the magnitude and phase of all the zero-phase currents flowing through the plurality of distribution lines, it is possible to improve the reliability of cutting off the distribution line in which the ground fault has occurred.

It is a figure for demonstrating the protective relay apparatus 10 by one Example of this invention. It is a block diagram which shows the structure of the protective relay apparatus 10 shown in FIG. The first or second bus 1 _1, 1 ₂ when the ground fault (bus ground fault) occurs in the first to sixth zero-phase current I ₀₁ ~I ₀₆ of amplitude and phase of which are shown in FIG. 1 It is a graph which shows an example. It shows the first of the first to an example of the sixth zero-phase current I ₀₁ ~I ₀₆ amplitude and phase when the ground fault (distribution line ground fault) occurs in the distribution line 2 ₁ shown in FIG. 1 It is a graph. It is a flowchart for demonstrating operation | movement when the bus-line ground fault accident and distribution line ground fault accident of the protective relay apparatus 10 shown in FIG. 1 generate | occur | produced. It is a flowchart for demonstrating operation | movement when the bus-line ground fault accident of the protective relay apparatus 10 shown in FIG. 1 generate | occur | produced. It is a flowchart for demonstrating operation | movement when the bus-line ground fault accident of the protective relay apparatus 10 shown in FIG. 1 generate | occur | produced. It is a flowchart for demonstrating operation | movement when the distribution line ground fault accident of the protective relay apparatus 10 shown in FIG. 1 generate | occur | produced. Bus ground fault or distribution line ground fault when the first and second ground fault sequence circuit breakers installed on the secondary side of the first and second transformers 3 ₁ and 3 ₂ are not used. It is a figure for demonstrating the conventional coping method when an accident generate | occur | produces.

  For the above purpose, when both the first and second zero-phase voltages exceed the zero-phase voltage set value, the phase of any one of the zero-phase currents flowing through the plurality of distribution lines is determined. When all other zero-phase currents are within the predetermined angle range, a trip signal is generated to shut off the bus bar breaker, and only the first zero phase voltage after the bus bar breaker is cut off. When the value exceeds the zero-phase voltage set value, a trip signal is generated to shut off the first power receiving circuit breaker. When only the second zero-phase voltage exceeds the zero-phase voltage set value, the second signal is output. This was realized by generating a trip signal that shuts off the power breaker.

Hereinafter, embodiments of the protective relay device of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the protective relay device 10 according to one embodiment of the present invention has a bus contact breaker contact signal S ₀ input from the bus contact breaker 4 indicating that “the bus contact breaker 4 is in an on state”. , And input from first and second ground fault sequence circuit breakers (not shown) respectively installed on the secondary sides of the first and second transformers 3 ₁ and 3 ₂ . The first bus 1 ₁ when the first and second ground fault sequence breaker contact signals S ₁ , S ₂ indicate “the first and second ground fault sequence breakers are off”. the first earth type potential transformer (GPT) 9 ₁ and the first zero-phase voltage V ₀₁ supplied from the second earth type instrument transformer installed second to bus 1 ₂ installed in 9 ₂ second zero-phase voltage V ₀₂ supplied from the first to the protective relay of the 6 installed respectively on the distribution line 2 ₁ to 2 ₆ in the first to sixth Based on the _first to _sixth zero-phase currents I _{01 to} I ₀₆ input from the device zero-phase current transformers (ZCT) 81 to 86, a bus ground fault or a distribution line ground fault has occurred. interrupting upon detection, the first to sixth breaker (distribution line breaker) ₆₁ through ₆ breaker distribution line ground fault has been installed in the distribution line generated out of the time distribution line ground fault that Trip signal (corresponding to the _{first to} sixth trip signals TR _{1 to} TR ₆ ), the seventh trip signal TR ₇ for breaking the bus bar breaker 4 in the event of a bus ground fault, and the Of the first and second power receiving circuit breakers 4 ₁ and 4 ₂ , the power receiving circuit breaker (first or second power receiving circuit breaker 4 ₁ , 4 ₂ ) on the bus side where the bus ground fault has occurred is interrupted. To output a trip signal (corresponding to the eighth and ninth trip signals TR ₈ and TR ₉ ) belongs to.

  As shown in FIG. 2, the protective relay device 10 includes an analog input unit 20, a set value memory 30, a relay determination unit 40, a processing unit 50, and an output unit 60. The analog input unit 20, the set value memory 30, the relay determination unit 40, the processing unit 50, and the output unit 60 are connected via a bus.

  Here, the analog input unit 20 includes an input converter 21, a band pass filter 22 (hereinafter referred to as “BPF 22”), and a sampling hold circuit 23 (hereinafter referred to as “S / H circuit 23”). And a multiplexer circuit 24 (hereinafter referred to as “MPX circuit 24”) and an analog / digital converter 25 (hereinafter referred to as “A / D converter 25”).

The BPF 22 is connected to the first to sixth protective relay device zero-phase current transformers 8 ₁ to 8 ₆ and the first and second grounded transformers 9 ₁ and 9 ₂ through the input converter 21. Only the input first to sixth zero-phase currents I _{01 to} I ₀₆ and the AC components of the first and second zero-phase voltages V ₀₁ and V ₀₂ (for example, commercial frequency 60 Hz) are extracted.
The S / H circuit 23 samples and holds the output signal of the BPF 22 at a predetermined sampling frequency (for example, 5760 Hz (electrical angle 3.75 ° in the case of a commercial frequency of 60 Hz)).
The MPX circuit 24 switches the output signal of the S / H circuit 23 and outputs it to the A / D converter 25.
The A / D converter 25 converts the analog first to sixth zero-phase currents I _{01 to} I ₀₆ and the AC components of the first and second zero-phase voltages V ₀₁ and V ₀₂ inputted from the MPX circuit 24. The digital first to sixth zero-phase currents I _{01 to} I ₀₆ and the AC components of the first and second zero-phase voltages V ₀₁ and V ₀₂ (hereinafter referred to as “first to sixth zeros unless otherwise specified”). Phase currents I _{01 to} I ₀₆ ”and“ first and second zero-phase voltages V ₀₁ and V ₀₂ ”).

The set value memory 30 is for storing various set values such as the zero-phase voltage set value V ₀₀ input from the set panel 100.
At this time, increased by the amount earth capacitance of the busbar breaker 4 bus 1 ₂ when the second is in the ON state is connected to the first bus 1 _1, first and second bus bars 1 _1, 1 first to sixth first to zero-phase voltage detection sensitivity of the sixth ground directional relay 5 ₁ to 5 _6, which are respectively installed on the distribution line 2 ₁ to 2 _{6 to 2} branched from a decrease To do. Therefore, the zero phase voltage settling value V ₀₀ is set as follows.
Fault resistance R = 3000 ohms first bus 1 ₁ of the first zero-phase voltage average value V _0AVE1 and second bus 1 ₂ of each phase of the zero-phase of each phase of the zero-phase voltage V ₀ which ground fault of Using the second zero-phase voltage average value V _0AVE2 of the voltage V ₀ , the bus characteristics of the first and second buses 1 ₁ and 1 ₂ are obtained by an artificial ground fault test, and the first bus 1 is calculated using the following equation: Request ₁ and the first earth capacitance C ₁ of the distribution line system and a second earth capacitance C ₂ of the second bus 1 ₂ distribution line system.
V _0AVE1 = E / {1+ ( _{ωC 1} R) ² } ^1/2
V _0AVE2 = E / {1+ ( _{ωC 2} R) ² } ^1/2
Here, E is obtained from the first and second ground capacitances C ₁ and C _{2 obtained} from the bus voltage using the following equation to obtain the zero-phase voltage V ₀ at the time of ground fault of the ground fault resistance R = 6000Ω. The obtained zero-phase voltage V ₀ is set as a zero-phase voltage set value V ₀₀ .
V ₀₀ = E / [1+ {ω ((C ₁ + C ₂ ) R)} ² ] ^1/2

The relay determination unit 40 receives a bus contact breaker contact signal S ₀ indicating that the bus contact breaker 4 is in the on state from the bus contact breaker 4 and the “first and second ground faults”. When the first and second ground fault sequence breaker contact signals S ₁ and S ₂ indicating that the sequence breaker is in the off state are input from the first and second ground fault sequence breakers, respectively, The first and second zero-phase voltages V ₀₁ and V ₀₂ input from the input unit 20 are compared with the zero-phase voltage set value V ₀₀ read from the set value memory 30, and the comparison result signal is sent to the processing unit 50. Output.
That is, the relay determination unit 40 outputs a comparison result signal indicating that “the first and second zero phase voltages V ₀₁ and V ₀₂ both exceed the zero phase voltage set value V ₀₀ ”, “the first zero phase voltage. Comparison result signal indicating that only V ₀₁ exceeds the zero phase voltage set value V ₀₀ , Comparison result signal indicating that only the second zero phase voltage V ₀₂ exceeds the zero phase voltage set value V ₀₀ Alternatively, a comparison result signal indicating that “the first and second zero-phase voltages V ₀₁ and V ₀₂ do not exceed the zero-phase voltage set value V ₀₀ ” is output to the processing unit 50.

In addition, the relay determination unit 40 receives a seventh trip signal TR ₇ from a trip signal generation unit 53 to be described later, and then receives a bus contact breaker contact signal indicating that the bus contact breaker 4 is in the off state. When S ₀ is input from the bus bar breaker 4, the first and second zero phase voltages V ₀₁ and V ₀₂ input from the analog input unit 20 and the zero phase voltage set value V read from the set value memory 30. ₀₀ are compared with the case where only the first zero-phase voltage V ₀₁ exceeds the zero-phase voltage set value V ₀₀ is a trip signal TR of the eighth to cut off the first power receiving breaker 4 _{1 When} a trip signal generation instruction signal instructing to generate ₈ is output to the processing unit 50 and only the second zero-phase voltage V ₀₂ exceeds the zero-phase voltage set value V ₀₀ , the second power receiving finger to generate a trip signal TR ₉ ninth to block the use breaker 4 ₂ The trip signal generation instruction signal shown is output to the processing unit 50.
The trip signal generation circuit 53 of the processing unit 50 generates the eighth or ninth trip signal TR ₈ , TR ₉ according to the trip signal generation instruction signal input from the relay determination unit 40, and generates the generated eighth or ninth trip signal. The ninth trip signals TR ₈ and TR ₉ are output to the output unit 60.

The processing unit 50 includes a maximum zero phase current detection unit 51, a phase comparison unit 52, and a trip signal generation unit 53.
The maximum zero-phase current detection unit 51 and the phase comparison unit 52 are for detecting a bus ground fault and a distribution line ground fault based on the following concept.

(1) Bus Ground Fault Detection Method For example, in a bus ground fault of a 6 kV distribution system, _first to _sixth zero-phase currents I ₀₁ to flow through _first to _sixth distribution lines 21 to ₂₆ , respectively. All I ₀₆ flows in the direction of flowing into the first and second buses 1 ₁ and 1 ₂ (see FIGS. 3A and 3B).
Therefore, the phase of the largest zero-phase current I ₀ is compared with the phase of the other zero-phase current I ₀ , and the latter is all within the predetermined angle range of the former (for example, within a range of ± 90 °). In this case, it is determined that “a bus ground fault has occurred”.
Note that if the "OFF state" of the busbar breaker 4 from the "ON state", when the ground fault occurs in the first bus 1 _1, the first zero-phase voltage V ₀₁ is the zero-phase voltage set value V Although remained above the ₀₀ second zero-phase voltage V ₀₂ becomes a zero-phase voltage set value V ₀₀ or less, whereas, when the ground fault occurs in the second bus 1 _2, the second zero-phase voltage V ₀₂ remains above the zero-phase voltage setting value V ₀₀ , but the first zero-phase voltage V ₀₁ is equal to or less than the zero-phase voltage setting value V ₀₀ .
Therefore, when the relay determination unit 40 changes the bus bar breaker 4 from the “ON” state to the “OFF” state, only the first zero-phase voltage V ₀₁ exceeds the zero-phase voltage settling value V _00. the judges' first at bus 1 ₁ ground fault has occurred, "and, in the case where only the second zero-phase voltage V ₀₂ exceeds the zero-phase voltage set value V ₀₀ is" second It is determined that a ground fault has occurred at bus 1 of ₂ ”.

(2) Distribution line ground fault detection method For example, in the case of a ground fault in a 6 kV distribution system, the zero-phase current I ₀ flowing through the fault line (the distribution line in which the ground fault occurred) is a healthy line (a ground fault occurs). since the the sum of the zero-phase current I ₀ flowing through the distribution line) other than the distribution line, the largest zero-phase current I ₀ in all lines (first to sixth distribution line 2 ₁ to 2 ₆₎ flow line has a high probability of accidents line, also, the zero-phase current I ₀ flowing through the accident line zero-phase current I ₀ and phase flowing healthy line is reversed (the first earth fault in distribution line 2 ₁ FIG. 4A and FIG. 4B show an example of the amplitude and phase of the first to sixth zero-phase currents I _{01 to} I ₀₆ at the time of occurrence of the problem.
Therefore, the phase of the largest zero-phase current I ₀ is compared with the phase of the other zero-phase current I ₀ , and the latter is all outside the predetermined angle range of the former (for example, outside the range of ± 90 °). In this case, it is assumed that the line through which the largest zero-phase current I ₀ flows is the accident line.

In order to detect a bus ground fault and a distribution line ground fault based on the concept as described above, the maximum zero phase current detection unit 51 has “the first and second zero phase voltages V ₀₁ and V ₀₂ are When the comparison result signal indicating that both have exceeded the zero-phase voltage settling value V ₀₀ is input from the relay determination unit 40, the first to sixth zero-phase currents I _{01 to} I input from the analog input unit 20 The absolute value of ₀₆ is obtained, and the zero phase current having the largest obtained absolute value is defined as the maximum zero phase current I _0MAX .

The phase comparison unit 52 is one of the first to sixth zero-phase currents I _{01 to} I ₀₆ input from the analog input unit 20 other than the maximum zero-phase current I _0MAX input from the maximum zero-phase current detection unit 51. It is examined whether or not all the phases are within the range of ± 90 ° with respect to the phase of the maximum zero-phase current I _0MAX .

As a result, in the range of ± 90 ° with respect to the first to sixth zero-phase current I ₀₁ ~I maximum zero-phase current I _0max than those of the phase of the maximum zero-phase current I _0max all phases of the ₀₆ In this case, the phase comparison unit 52 outputs a trip signal generation instruction signal for instructing to generate the _seventh trip signal TR ₇ for interrupting the bus bar breaker 4 to the trip signal generation circuit 53.
At this time, the trip signal generation circuit 53 generates a seventh trip signal TR ₇ that shuts off the bus bar breaker 4 in response to the trip signal generation instruction signal input from the phase comparison unit 52, and generates the generated _seventh trip signal TR 7. Trip signal TR ₇ is output to relay determination unit 40 and output unit 60.

On the other hand, if outside the range of ± 90 ° with respect to the first to sixth zero-phase current I ₀₁ ~I maximum zero-phase current I _0max than those of the phase of the maximum zero-phase current I _0max all phases of the ₀₆ The phase comparison unit 52 distributes the distribution line (the _first to _sixth distribution lines 2 ₁ to 2 ₆₎ through which the maximum zero-phase current I _0MAX flows among the first to sixth zero-phase currents I _{01 to} I _06. Trip signal (first to sixth trip signals) for breaking a circuit breaker (any one of the _{first to} sixth circuit breakers 6 _{1 to} 6 ₆ ) installed in any one of them. A trip signal generation instruction signal for instructing to generate any one of TR _{1 to} TR ₆ is output to the trip signal generation circuit 53.
At this time, the trip signal generation circuit 53 generates the maximum zero-phase current I _0MAX among the first to sixth zero-phase currents I _{01 to} I ₀₆ according to the trip signal generation instruction signal input from the phase comparison unit 52. A trip signal for breaking the circuit breaker installed on the distribution line that has flowed is generated, and the generated trip signal is output to the output unit 60.

The output unit 60 outputs the trip signal input from the trip signal generation circuit 53 to the corresponding circuit breaker with a predetermined operation time limit.
The _{first to} sixth trip signals TR _{1 to} TR ₆ that actuate the first to sixth circuit breakers 6 _{1 to} 6 ₆ are operated in the _first to _sixth distribution lines 21 to ₂₆ . In order to use the protective relay device 10 as a back-up protection for the first to _sixth ground fault direction relays 5 _{1 to} 5 ₆ (see FIG. 1) respectively installed, the first to sixth ground fault direction relays 5 Given the timed coordination with _{1-5 6,} it is slower than the first to sixth earth fault directional relay 5 ₁ to 5 ₆ operation timed in (for example, 0.7 s) (e.g., 1s).
In addition, the operation time limit of the _seventh trip signal TR ₇ for interrupting the bus bar breaker 4 is a bus ground fault when both the main protection and the protection for detecting the distribution line ground fault do not operate. Since the possibility is very large, for example, 3 s is set.
Further, the operation time limits of the eighth and ninth trip signals TR ₈ and TR ₉ for shutting off the first and second power receiving circuit breakers 4 ₁ and 4 ₂ are the same even if the bus bar breaker 4 is shut off. For example, 3.5 s is set because the accident is continuously involved.

Next, and not to operate the first and second ground fault sequence breaker with first fault in the transformer 3 ₁ to enter state busbar breaker 4 for its repair work occurs The operation of the protective relay device 10 when a bus ground fault occurs sometimes will be described with reference to the flowcharts shown in FIGS.

When the first transformer 3 ₁ failure has occurred first and second ground fault sequence breaker with the busbar breaker 4 is in the ON state for that repair work is to not work, A bus contact breaker contact signal S ₀ indicating that “the bus contact breaker 4 is in the on state” is input from the bus contact breaker 4 to the protective relay device 10 and “the first and second ground faults”. First and second ground fault sequence breaker contact signals S ₁ and S ₂ indicating that the sequence breaker is in the off state are respectively sent from the first and second ground fault sequence breakers to the protective relay 10. Input (step S11 in FIG. 5).

Thereafter, when a ground fault occurs in the first or second bus 1 ₁ , 1 ₂ , the _first to _sixth zero-phase currents I ₀₁ to I 6 flowing in the first to _sixth distribution lines 2 ₁ to 2 ₆ , respectively. I ₀₆ is input to the protective relay device 10 from the _first to _sixth protective relay zero-phase current transformers 8 ₁ to 86 and generated on the first and second buses 1 ₁ and 1 ₂ , respectively. The first and second zero-phase voltages V ₀₁ and V ₀₂ are input to the protective relay device 10 from the first and second grounded-type instrument transformers 9 ₁ and 9 ₂ , respectively.
The analog first to sixth zero-phase currents I _{01 to} I ₀₆ and the first and second zero-phase voltages V ₀₁ and V ₀₂ are converted into digital first to sixth digital signals at the analog input unit 20 of the protective relay device 10. The sixth zero-phase currents I _{01 to} I ₀₆ and the first and second zero-phase voltages V ₀₁ and V ₀₂ are converted (step S12).

The relay determination unit 40 indicates that the bus contact breaker contact signal S ₀ indicates “the bus contact breaker 4 is in the on state”, and the first and second ground fault sequence breaker contact signals S ₁ , S ₂ indicates that “the first and second ground fault sequential circuit breakers are in the OFF state”, respectively, and therefore the first and second zero-phase voltages V ₀₁ and V ₀₂ input from the analog input unit 20 And the zero phase voltage set value V ₀₀ read from the set value memory 30, and if both the first and second zero phase voltages V ₀₁ and V ₀₂ exceed the zero phase voltage set value V ₀₀ , A comparison result signal indicating that is output to the processing unit 50 (step S13).

The maximum zero-phase current detection unit 51 of the processing unit 50 determines that the comparison result signal indicating that “the first and second zero-phase voltages V ₀₁ and V ₀₂ both exceed the zero-phase voltage set value V ₀₀ ” is a relay determination. When input from the unit 40, the absolute values of the first to sixth zero-phase currents I _{01 to} I ₀₆ input from the analog input unit 20 are obtained, and then the maximum zero-phase current I _0MAX is obtained. Here, it is assumed that the first zero-phase current I ₀₁ is the maximum zero-phase current I _0MAX .
In addition, the phase comparison unit 52 has all the phases of the second to sixth zero-phase currents I _{02 to} I ₀₆ out of the first to sixth zero-phase currents I _{01 to} I ₀₆ input from the analog input unit 20. Whether or not the phase is within ± 90 ° with respect to the phase of the maximum zero-phase current I _0MAX (first zero-phase current I ₀₁ ) is checked (step S14).

In the case of a bus ground fault, the phases of the second to sixth zero-phase currents I _{02 to} I ₀₆ are all ± 90 ° with respect to the phase of the maximum zero-phase current I _0MAX (first zero-phase current I ₀₁ ). Therefore, the phase comparison unit 52 outputs to the trip signal generation circuit 53 a trip signal generation instruction signal for instructing to generate the _seventh trip signal TR ₇ for cutting off the bus bar breaker 4 ( Step S15 in FIG. 6).

The trip signal generation circuit 53 generates a seventh trip signal TR ₇ for cutting off the bus bar breaker 4 in response to the trip signal generation instruction signal input from the phase comparator 52, and generates the generated seventh trip signal. TR ₇ is output to relay determination unit 40 and output unit 60 (step S16).

The output unit 60 outputs the seventh trip signal TR ₇ input from the trip signal generation circuit 53 to the bus bar breaker 4 in a predetermined operation time period (for example, 3 s) (step S17).

After the seventh trip signal TR ₇ is input from the trip signal generator 53, the relay determination unit 40 receives the bus contact breaker contact signal S ₀ indicating that the bus contact breaker 4 is in the off state. When input from the contact breaker 4, the first and second zero phase voltages V ₀₁ and V ₀₂ input from the analog input unit 20 are compared with the zero phase voltage set value V ₀₀ read from the set value memory 30. (Steps S18 and S19).

As a result, when only the first zero-phase voltage V ₀₁ exceeds the zero-phase voltage set value V ₀₀ is the relay determining section 40, an eighth trip signal to cut off the first power receiving breaker 4 ₁ A trip signal generation instruction signal for instructing to generate TR ₈ is output to the trip signal generation circuit 53 of the processing unit 50 (step S20 in FIG. 7). On the other hand, in the case where only the second zero-phase voltage V ₀₂ exceeds the zero-phase voltage set value V ₀₀ is the relay judgment section 40, a trip signal TR of the ninth to cut off the second power receiving breaker 4 ₂ A trip signal generation instruction signal instructing to generate ₉ is output to the trip signal generation circuit 53 (step S23).

When the trip signal generation instruction signal for instructing to generate the _eighth trip signal TR ₈ is input from the relay determination unit 40, the trip signal generation circuit 53 generates the eighth trip signal TR ₈ and outputs it. outputs 60 (step S21), and the trip signal generation instruction signal instructing to generate a trip signal TR ₉ ninth is input from the relay determining unit 40, and generates a trip signal TR ₉ of 9 It outputs to the output part 60 (step S24).

The output unit 60 outputs the eighth or ninth trip signals TR ₈ and TR ₉ input from the trip signal generation circuit 53 to the first or second power receiving circuit breaker at a predetermined operation time (for example, 3.5 s). Output to 4 ₁ and 4 ₂ (steps S22 and S25).
As a result, the first or second power receiving circuit breaker 4 ₁ , 4 ₂ is interrupted by the protective relay device 10 according to the bus (first or second bus 1 ₁ , 1 ₂ ) where the ground fault occurred. Therefore, the _first to _sixth distribution lines 2 ₁ to 2 ₆ can be protected from the bus ground fault.

Next, and not to operate the first and second ground fault sequence breaker with first fault in the transformer 3 ₁ to enter state busbar breaker 4 for its repair work occurs the operation of the first distribution line 2 ₁ in the first earth fault directional relay 5 ₁ protective relay device when the ground fault so as not to operate occurs 10 when the flowchart shown in FIGS. 5 and 8 The description will be given with reference.

When the first transformer 3 ₁ failure has occurred first and second ground fault sequence breaker with the busbar breaker 4 is in the ON state for that repair work is to not work, A bus contact breaker contact signal S ₀ indicating that “the bus contact breaker 4 is in the on state” is input from the bus contact breaker 4 to the protective relay device 10 and “the first and second ground faults”. First and second ground fault sequence breaker contact signals S ₁ and S ₂ indicating that the sequence breaker is in the off state are respectively sent from the first and second ground fault sequence breakers to the protective relay 10. Input (step S11 in FIG. 5).

Thereafter, the first earth fault in distribution line 2 ₁ is generated, the zero-phase current I ₀₁ ~I ₀₆ of the first to sixth respectively flowing in the distribution line 2 ₁ to 2 ₆ of the first to sixth first To the sixth relay zero-phase current transformers 8 ₁ to 8 ₆ for the protective relay 10 and the first and second buses 1 ₁ and 1 ₂ generated on the first and _second buses 1 1 and 12, respectively. Zero-phase voltages V ₀₁ and V ₀₂ are input to the protective relay device 10 from the first and second grounded-type instrument transformers 9 ₁ and 9 ₂ .
The analog first to sixth zero-phase currents I _{01 to} I ₀₆ and the first and second zero-phase voltages V ₀₁ and V ₀₂ are converted into digital first to sixth digital signals at the analog input unit 20 of the protective relay device 10. The sixth zero-phase currents I _{01 to} I ₀₆ and the first and second zero-phase voltages V ₀₁ and V ₀₂ are converted (step S12).

The relay determination unit 40 indicates that the bus contact breaker contact signal S ₀ indicates “the bus contact breaker 4 is in the on state”, and the first and second ground fault sequence breaker contact signals S ₁ , S ₂ indicates that “the first and second ground fault sequential circuit breakers are in the OFF state”, respectively, and therefore the first and second zero-phase voltages V ₀₁ and V ₀₂ input from the analog input unit 20 And the zero phase voltage set value V ₀₀ read from the set value memory 30, and if both the first and second zero phase voltages V ₀₁ and V ₀₂ exceed the zero phase voltage set value V ₀₀ , A comparison result signal indicating that is output to the processing unit 50 (step S13).

The maximum zero-phase current detection unit 51 of the processing unit 50 determines that the comparison result signal indicating that “the first and second zero-phase voltages V ₀₁ and V ₀₂ both exceed the zero-phase voltage set value V ₀₀ ” is a relay determination. When input from the unit 40, the absolute values of the first to sixth zero-phase currents I _{01 to} I ₀₆ input from the analog input unit 20 are obtained, and then the maximum zero-phase current I _0MAX is obtained. In this example, since the ground fault occurs in the first distribution line 2 _1, the first zero-phase current I ₀₁ is the maximum zero-phase current I _0max.
In addition, the phase comparison unit 52 has all the phases of the second to sixth zero-phase currents I _{02 to} I ₀₆ out of the first to sixth zero-phase currents I _{01 to} I ₀₆ input from the analog input unit 20. Whether or not the phase is within ± 90 ° with respect to the phase of the maximum zero-phase current I _0MAX (first zero-phase current I ₀₁ ) is checked (step S14).

In this case, the phases of the second to sixth zero-phase currents I _{02 to} I ₀₆ are all outside the range of ± 90 ° with respect to the phase of the maximum zero-phase current I _0MAX (first zero-phase current I ₀₁ ). _Therefore , the phase comparison unit 52 blocks the first circuit breaker 6 ₁ installed in the _first distribution line 2 _{1 in} which the maximum zero-phase current I _0MAX (first zero-phase current I ₀₁ ) flows. A trip signal generation instruction signal for instructing to generate the first trip signal TR ₁ is output to the trip signal generation circuit 53 (step S26 in FIG. 8).

Trip signal generating circuit 53 in response to the trip signal generation instruction signal input from the phase comparator 52, the first trip signal TR ₁ to cut off the first circuit breaker ₆₁ occurs, the first generated and it outputs a trip signal TR ₁ to the output unit 60 (step S27).

The output unit 60 outputs the first trip signal TR ₁ inputted from the trip signal generating circuit 53 a predetermined operation time period (for example, 1s) in the first circuit breaker ₆₁ (step S28).
Thus, even when this distribution line ground fault first earth fault directional relay 5 ₁ did not work, because the first circuit breaker ₆₁ is blocked by protective relay device 10, the distribution line locations It is possible to protect the _first to _sixth distribution lines 2 ₁ to 2 ₆ from a cable accident.

In the above description, the processing unit 50 of the protective relay device 10 includes the maximum zero-phase current detection unit 51 to cope with both the bus ground fault and the distribution line ground fault. In the case where it is sufficient to deal with only the maximum zero-phase current detector 51, it is not necessary to provide the maximum zero-phase current detector 51.
In this case, the phase comparison unit 52 of the processing unit 50 outputs another 5 phase to any one of the first to sixth zero-phase currents I _{01 to} I ₀₆ input from the analog input unit 20. It is only necessary to check whether the phases of the two zero-phase currents are all within a range of ± 90 °.

Further, the protective relay device 10 has been used for backup protection of the first to earth fault directional relay 5 ₁ to 5 ₆ 6 may be used protective relay device 10 as a main protective relay device.

Further, when there are _first to _sixth residual zero-phase currents flowing through the first to _sixth distribution lines 2 ₁ to 2 ₆ when no bus ground fault or distribution line ground fault has occurred. The maximum zero-phase current detection unit 51 subtracts the first to sixth residual zero-phase currents from the first to sixth zero-phase currents I _{01 to} I ₀₆ input from the analog input unit 20, respectively. The maximum zero-phase current I _0MAX may be detected.
The same applies to the phase comparison unit 52.

1 ₁ , 1 ₂ 1st and 2nd busbars 2 1-2 _{6 1st} to _6th distribution lines 3 ₁ , 3 ₂ 1st and 2nd transformers 4 Bus line breakers 4 ₁ , 4 ₂ 1 and a second power receiving breaker 5 ₁ to 5 ₆ first to sixth earth fault directional relay ₆₁ through ₆ first to sixth breaker 7 _{1-7 6} zero phase of the first to sixth of Current transformers 8 ₁ to 8 ₆ Zero-phase current transformers 9 ₁ and 9 ₂ for _first to _sixth protection relay devices First and second earthing-type instrument transformers 10 Protection relay device 20 Analog input unit 21 Input converter 22 BPF
23 S / H circuit 24 MPX circuit 25 A / D converter 30 Setting value memory 40 Relay determination unit 50 Processing unit 51 Maximum zero-phase current detection unit 52 Phase comparison unit 53 Trip signal generation unit 60 Output unit 100 Setting panel V ₀ zero Phase voltage V ₀₁ , V ₀₂ first and second zero phase voltage V ₀₀ zero phase voltage set value V _0AVE1 , V _0AVE2 first and second zero phase voltage average values I _{01 to} I ₀₆ first to sixth Zero-phase current I _0MAX Maximum zero-phase current S _{0 Bus} connection circuit breaker contact signals S ₁ , S ₂ First and second ground fault sequence circuit breaker contact signals TR ₁ -TR ₉ First to ninth trip signals C ₁ , C ₂ first and second ground capacitance E bus voltage S11 to S28 steps

Claims (3)

First and second power receiving circuit breakers (4 ₁ , 4 ₂ ) are respectively installed on the primary side of the first and second transformers (3 ₁ , 3 ₂ ), and the first transformer A busbar breaker (4) between the first busbar (1 ₁ ) connected to the secondary side of the second transformer and the second busbar (1 ₂ ) connected to the secondary side of the second transformer A protective relay device (10) used in the power system in which is installed,
First and second for interrupting a plurality of distribution lines (2 ₁ to 2 ₆ ) branched from the first and second buses in a predetermined order, with the bus bar breaker being in an on state. When the ground fault sequence circuit breaker of the first and second zero-phase voltages (V ₀₁ , V ₀₂ ) exceed the zero-phase voltage settling value (V ₀₀ ), When the phase of any one zero-phase current among the zero-phase currents (I _{01 to} I ₀₆ ) flowing through the distribution lines is all within a predetermined angle range, the bus connection A trip signal (TR ₇ ) for breaking the circuit breaker is generated, and when only the first zero-phase voltage exceeds the zero-phase voltage settling value after the bus bar breaker is cut off, trip signal to block one of the power receiving circuit breaker (TR ₈₎ occurs, the second zero-phase voltage Characterized by comprising a trip signal generating means (40, 50) for generating a trip signal for interrupting the second power receiving breakers (TR ₉₎ in the case but it exceeds the zero-phase voltage set value , Protective relay device. When the trip signal generating means is such that the phase of the largest zero phase current among the zero phase currents flowing through the plurality of distribution lines is all within a predetermined angle range with respect to the phase of the other zero phase current, The protective relay device according to claim 1, characterized in that a trip signal (TR ₇ ) for breaking the communication breaker is generated.   The protective relay device according to claim 1, wherein the predetermined angle range is ± 90 °.