JPH0548139Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an accident diagnosis device that can detect the presence or absence of an accident in a busbar or transformer at an electric station and the type of the accident.

(Prior Art) Conventionally, in an electric station, for example, a distribution substation, when a substation accident occurs, an overcurrent relay Ry ₁ or a ground fault voltage relay Ry ₂ is activated as shown in FIG.
By the circuit breaker on the primary winding side of the main transformer MTR
After opening CB ₁ , maintenance personnel go to the substation where the substation fault occurred, open circuit breakers CB2 to CBn connected to bus bar 1, and use an insulation resistance tester to determine whether the bus fault or transformer has occurred. The type of accident is diagnosed, such as whether or not there is an equipment accident, and whether it is a ground fault or short circuit. In addition, in this Figure 5,
The symbol GPT is a potential transformer.

(Problem to be solved by the invention) However, in order to diagnose the presence or absence of an accident in the conventional bus bar and transformer, and the type of the accident, it is necessary to use an insulation resistance tester, etc. diagnosis is troublesome, and
Maintenance personnel go to the substation where the accident occurred to diagnose the accident, so it takes a long time to diagnose the accident.
There were problems such as not being able to immediately begin work to restore power.

(Purpose of the invention) This invention was made in view of the above circumstances, and its purpose is to easily detect busbar accidents and main transformer accidents, and diagnose their accident forms. The purpose is to provide an accident diagnosis device.

(Means for Solving the Problem) This invention connects each phase of the bus bar, which is connected to the secondary side of the main transformer installed in the electric station via the circuit breaker, through the secondary winding. an auxiliary transformer that generates fault detection voltage; a current detector that detects the current flowing in each phase of the bus using the voltage generated by the auxiliary transformer; a voltage detector that detects the voltage of each phase; and an accident determination device that determines whether or not an accident has occurred in the bus or the transformer and its type from the current emitted by the current detector and the voltage detected by the voltage detector. It is equipped with the following.

It is also equipped with a remote device that opens and closes the circuit breaker and accident diagnosis switch by remote control.

(Function) According to the accident diagnosis device according to this invention, when an accident occurs, the circuit breaker is turned off and AC voltage is injected into each phase of the bus bar by the auxiliary transformer. Then, a detection voltage is generated in each phase of the bus.
The current detector detects the current flowing through each phase of the bus, the voltage detector detects the voltage of each phase of the bus, and the fault detector detects a bus fault based on the output of the current detector and the output of the voltage detector. If there is no abnormality, the circuit breaker is turned on and the presence or absence of a transformer accident and the type of the accident are determined.

Furthermore, the circuit breaker and accident diagnosis switch can be opened and closed remotely using a remote device.

(Example) Below, the accident diagnosis device according to this invention will be described as follows:
An embodiment applied to a bus bar 1 consisting of three phases, an S phase and a T phase, will be described with reference to the drawings.

In FIG. 1, 2 is an auxiliary transformer. This auxiliary transformer 2 has a primary winding 3 and a secondary winding 4, and the primary winding 3 and the secondary winding 4 are star-connected. The secondary winding 4 is the R phase of the bus 1,
They are connected to the S phase and T phase, respectively. A three-phase alternating current voltage is applied to the primary winding 3, and 5 is a three-phase alternating current power source.

And each phase 3 of the primary winding 3 of the auxiliary transformer 2
impedances 6a, 6b, 6 for limiting the current flowing through each phase 3a, 3b, 3c of the primary winding 3 between the a, 3b, 3c and the three-phase AC power supply 5.
c, and current transformers (current detectors) 7a, 7b, which detect the current flowing through the primary windings 3a, 3b, 3c.
7c and accident diagnosis switches 8a, 8b, and 8c are respectively connected. By the way, current transformer 7
The output currents of a, 7b, and 7c are input to an input terminal U of an accident detection device (accident determination device) 12, which will be described later.

An AC voltage E corresponding to each AC voltage of each phase 3a to 3c of the primary winding 3 is induced in each phase 4a to 4c of the secondary winding 4 of the auxiliary transformer 2. E is applied to each phase R, S, T of bus 1. That is, the auxiliary transformer 2 generates the fault detection voltage E to each phase R, S, and T of the bus bar.

Reference numeral 9 denotes an instrument transformer in which each phase 10a to 10c of the primary winding 10 is connected to each phase R, S, and T of the bus 1, and each phase 11a to 11c of the secondary winding 11 is connected to an accident detection device. (Accident determiner) Connected to input terminal Q of 12. This instrument transformer 9 functions as a voltage detector that detects the voltage of each phase R and ST of the bus 1.

The accident detection device 12 includes current transformers 7a, 7b, and 7c.
The current value detected by the sensor is compared with a preset current value, and when the detected current value is greater than or equal to the set current value, it is determined that a short circuit accident has occurred. This is designed so that when any of the phases R, S, and T of bus bar 1 is short-circuited, an overcurrent flows through the short-circuited phases R, S, and T, and this overcurrent is detected via transformer 2. (In other words, an overcurrent flows through the phase of the secondary winding 4 and primary winding 3 of the transformer 2 corresponding to the shorted phase of the bus 1, and the overcurrent of that phase is detected.) . In addition, as an overcurrent detector, switches 8a to 8a are automatically activated due to overcurrent.
It may be something like a circuit breaker in which 8c is opened.

Further, the accident detection device 12 determines the zero-sequence voltage from the detected voltage of each phase 11a to 11c of the secondary winding 11 of the potential transformer 9, and compares it with a preset voltage to determine whether the zero-sequence voltage is set. When the voltage exceeds the voltage, it is determined that a ground fault has occurred. 13
is a warning display contact that warns of an accident.

The zero-phase voltage may be taken from an open delta circuit of the tertiary winding of the potential transformer 9 (not shown).

Note that a measuring instrument such as a voltmeter (not shown) is connected to the secondary winding 11 of the instrument transformer 9, and a measuring instrument such as a voltmeter (not shown) is connected to the bus bar 1. CBn is connected.

By the way, the circuit breakers CB1 to CBn and the accident diagnosis switches 8a to 8c can be opened and closed by remote control from a remote device. The remote device includes, for example, a solenoid that opens and closes each of the circuit breakers CB2 to CBn and the accident diagnosis switches 8a to 8c, a driver that supplies current to the solenoid, and a transmitter that remotely controls the driver.

Next, the operation of the accident diagnosis device constructed as described above will be explained.

Now, an accident has occurred on bus 1 or main transformer MTR (see Figure 5), and overcurrent relay Ry ₁ (5th
(see figure) or when circuit breaker CB1 on the primary side of main transformer MTR is opened by earth fault voltage relay Ry ₂ , operate a transmitter (not shown) to open circuit breakers CB2 to CBn connected to bus 1. Along with opening up
The accident diagnosis switches 8a to 8c are turned on. In this way, since the transmitter remotely opens and closes the circuit breakers CB2 to CBn and the accident diagnosis switches 8a to 8c, there is no need for maintenance personnel to go to the site.

Then, current is passed through the primary winding 3 of the auxiliary transformer 2. Then, an alternating current voltage E is induced in the secondary winding 4 and applied to each phase R, S, and T of the bus 1. As a result, an alternating current flows through each phase R, S, and T of the bus 1, and each phase 10a of the primary winding 10 of the potential transformer 9
~10c, an alternating current flows through its secondary winding 11
AC voltage is induced in each phase 11a to 11c.

Here, for example, if the S phase and T phase of the bus 1 are short-circuited, an overcurrent will flow through the S phase and T phase, and the primary winding 3 of the auxiliary transformer 2 corresponding to the S phase and T phase will An overcurrent also flows through phases 3b and 3b. On the other hand, the current transformers 7a, 7b, 7c are connected to each phase 3a to 3 of the primary winding 3.
Accident detection device 12 detects the current flowing through 3c.
compares the detected current value with a preset set current value, and in this case, since the detected current values of the current transformers 7b and 7c are equal to or higher than the set current value, the fault detection device 12 connects the S phase and It is determined that there is a short circuit with the T phase. Short-circuit accidents can be detected in the same way for other phases.

In this way, it is possible to detect which phase is shorted.

Next, the case of a ground fault will be explained.

For example, if the T phase of the bus 1 has a ground fault, the potential of that T phase will drop and the primary winding 1 of the potential transformer 9 will be
0 phase 10c decreases, its secondary winding 11
The potential of phase 11c also decreases. Accident detection device 12
is each phase 11a of the secondary winding 11 of the instrument transformer 9.
The zero-sequence voltage is determined from the voltage of ~11c, and this electric-phase voltage is compared with a preset set voltage, and if the zero-sequence voltage exceeds the set voltage, it is determined that a ground fault has occurred. In this case, since the voltage of the phase 11c is lower than that of other healthy phases, the accident determination device 12 determines that the T phase of the bus 1 has a ground fault. A ground fault in any other phase of the bus 1 is detected in the same manner.

When the bus 1 has neither a ground fault nor a short circuit, that is, when the fault detection device 12 does not detect a fault on the bus 1, if the circuit breaker CB ₂ shown in FIG. 5 is turned on,
Main transformer short circuits and ground faults are detected in the same manner as above. Furthermore, by setting the set current value to an appropriate value, it is also possible to detect the rarity of the winding of the main transformer MTR.

By the way, in the case of a one-wire ground fault or a two-wire short circuit, the voltage and current vectors have different phase angles compared to normal conditions, as shown in Figure 2. can also be detected. In addition, in the case of a one-line short circuit or a two-line short circuit, the voltage value changes compared to when the line is healthy, so it is also possible to detect a short circuit or a ground fault using only the voltage. In this case, keep the ground fault detection voltage sufficiently low.

In addition, in the above embodiment, overcurrent of each phase R, S, and T of bus bar 1 is detected via transformer 2.
The overcurrent of each phase R, S, and T of the bus 1 may be directly detected. Furthermore, although each of the transformers 2 and 9 is star-connected, short circuits and ground faults can be detected in the same manner as described above even with other connections.

Further, in the above embodiment, the power source 5 is a three-phase AC power source, but it may be a single-phase AC power source. In this case, when detecting a ground fault, the switches 8a to 8c may be connected as shown in FIG. 3, and the switches 8a to 8c may be turned on one by one or all at the same time. When detecting a short circuit, connect as shown in Figure 4 and turn switch 8.
Sequentially add a to 8c.

(Effects of the invention) According to this invention, forms of accidents such as bus short circuits and ground faults can be detected easily and quickly. In addition, since the transmitter can open and close circuit breakers and fault diagnosis switches, there is no need for maintenance personnel to go to the site.Therefore, busbars and main transformers can be diagnosed quickly. They can begin work to restore power.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the accident diagnosis device according to the present invention, FIG. 2 is an explanatory diagram showing the relationship between voltage vector and current vector, and FIGS.
The figure is an explanatory diagram of another embodiment, and FIG. 5 is a busbar connection diagram used to explain an example of conventional busbar accident detection. 1... Bus bar, 2... Auxiliary transformer, 3... Primary winding, 4... Secondary winding, 5... Power supply, 7a, 7b,
7c...Current transformer, 9...Instrument transformer, 12...
Accident detection device, MTR...main transformer.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) For each phase of the busbar connected via a circuit breaker to the secondary side of the main transformer installed in the electric station,
an auxiliary transformer that generates a fault detection voltage via a secondary winding; a current detector that detects the current flowing through each phase of the bus using the voltage generated by the auxiliary transformer; and the auxiliary transformer. a voltage detector that detects the voltage of each phase of the bus generated by An accident diagnosis device that includes an accident determination device that determines the form of the accident. (2) For each phase of the busbar connected to the secondary side of the main transformer installed in the electric station via a circuit breaker,
an auxiliary transformer that generates an accident detection voltage via a secondary winding; an AC power supply that applies an alternating current voltage to the primary winding of the auxiliary transformer via an accident diagnosis switch; a current detector that detects the current flowing in each phase of the bus bar based on the voltage generated by the auxiliary transformer; a voltage detector that detects the voltage of each phase of the bus bar generated by the auxiliary transformer; an accident determination device that determines the presence or absence of an accident in the bus bar or the main transformer and its form based on the current detected by the voltage detector and the voltage detected by the voltage detector; and a remote device that opens and closes the circuit breaker and the switch by remote control. An accident diagnosis device equipped with