JPH06339228A - Reconnecting method for instantaneous voltage drop countermeasuring apparatus - Google Patents

Abstract

PURPOSE:To reset an instantaneous voltage drop countermeasuring apparatus to a system interconnecting operating state by using an automatic synchronously closing unit even when the closing unit is connected to a generator side breaker. CONSTITUTION:If a detecting.control circuit 2 does not satisfy setting conditions of a voltage difference of voltages V1, V2, a phase difference, a frequency difference, etc., when a system voltage is recovered after a semiconductor switch TS is opened, it outputs an open command to breakers 52G1, 52G2 through a sequential circuit 3, generates a zone A2 voltage drop, and allows the circuit 2 to detect the voltage drop. The switch TS is closed, power is supplied from a system side to loads L3, L4, a synchronous closing command is output to automatic synchronously closing units SY3, SY4, and outputs of generators G1, G2 are controlled. When it reaches detection setting conditions, the closing command is output from the units SY3, SY4 to the breakers 52G1, 52G2 to reset to an original interconnecting operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration system which is connected to a power system, in which the generator on the cogeneration side is down or the load is down or the load is down due to an instantaneous voltage drop on the power system side. The present invention relates to a reincorporation method of an instantaneous voltage reduction countermeasure device to prevent.

[0002]

2. Description of the Related Art Conventionally, a circuit using an instantaneous voltage drop countermeasure device in a cogeneration system which is connected to a power system is shown in FIG. In the figure, 52B is an interconnecting circuit breaker that interconnects the power system side and the generator side, 1 is an instantaneous voltage drop countermeasure device connected in series with the interconnecting circuit breaker, and L ₁ and L ₂ are power system side Internal load connected to the bus A ₁ , L ₃ and L ₄ are internal compensation loads connected to the generator side bus A ₂ , G ₁ and G ₂ are generators, and SY ₁ is disconnection It is an automatic synchronous loading device for loading the container 52B.

The instantaneous voltage countermeasure device 1 includes a power fuse PF.
Attached semiconductor switch TS and bypass circuit BC, and interconnecting breaker 52B by selecting semiconductor switch TS or bypass circuit
And a main circuit including disconnectors DS ₁ and DS ₂ connected to the bus A ₂ .

A detection circuit for detecting a frequency difference, a phase difference, a voltage difference between the input and output side voltages V ₁ and V _2, an instantaneous voltage drop, power supply, etc., and a semiconductor switching device controlled by the output of this detection circuit and the sequence circuit 3. With the detection / control circuit 2 that outputs the gate ON / OFF command of the device TS.

Interconnection circuit breaker 52B and disconnecting switches DS ₁ and DS ₂
Auxiliary contact signal detection / control circuit 2, operation / display circuit 5
A sequence circuit 3 for turning on the automatic synchronous closing device SY ₁ or controlling the detection / control circuit 2 by a signal from the like, and turning on / off of the semiconductor switch by the ON / OFF command of the detection / control circuit 2. It is composed of a gate drive circuit 4, an operation / display circuit 5, a voltage waveform recording / monitoring device 6, and the like.

When a power failure or voltage drop occurs on the system side, however, the instantaneous voltage drop countermeasure device 1 instantaneously detects the voltage drop and turns off the semiconductor switch TS within half a cycle to set the voltage of the generator G. The voltage of the loads L ₃ and L ₄ is compensated by minimizing the decrease.

The re-insertion method after power recovery is divided into the following two cases.

(1) The voltage drop time is long and the interconnection breaker 5
When 2B is also opened, the semiconductor switch TS is turned on by detecting the opening of the interconnection breaker 52B from the auxiliary contact signal indicating the open / closed state of the interconnection breaker 52B taken into the device. Then, this device gives a synchronous closing command to the existing automatic synchronous closing device SY ₁ to perform the operation with the interconnection breaker 52B.

(2) When power is restored immediately without opening the interconnection breaker 52B Power is restored in a very short time, so if there is almost no frequency difference and phase difference on the generator side with the system, both When the phase difference of the electrical angle is within 10 °, they are put in parallel. If the semiconductor switch TS is opened, the load on the generator side suddenly changes and the phase difference becomes 1
When it exceeds 0 °, the interconnection breaker 52B is also once opened, and re-closing is performed by the automatic synchronous closing device in the same procedure as (1). The conditions for re-entering the semiconductor switch TS are as follows (voltage difference is ± 10%,
The phase difference is ± 10 deg and the frequency difference is ± 1%).

[0010]

The circuit breaker to be closed by the automatic synchronizing closing device may be the breaker 52G1 or 52G2 on the private generator side, instead of the interconnection breaker 52B. This is because it takes time to perform synchronization at the interconnection breaker 52B due to fluctuations in the internal loads L3 and L4. If the generator-side circuit breakers 52G1 and 52G2 are used, the phases can be adjusted with the load of the generator being no load, so that the synchronous closing can be performed in a short time. However, in this case, the conventional methods (1) and (2) cannot be used.

The present invention has been made in view of the above problems of the prior art, and the object thereof is that the automatic synchronizing closing device is not on the interconnection breaker side but on the generator side breaker. Even in such a case, it is an object of the present invention to provide a method for reincorporating an instantaneous voltage drop countermeasure device that can return to a system interconnection operating state by using an automatic synchronous closing device.

[0012]

In order to achieve the above object, a method of reincorporating an instantaneous voltage reduction countermeasure device according to the present invention is a method for reincorporating an instantaneous voltage drop countermeasure device. In a system in which a series circuit is connected to the semiconductor switch of the voltage reduction countermeasure device and the automatic synchronous closing device is provided in the generator side circuit breaker, the system voltage after the interruption operation of the semiconductor switch in the momentary voltage reduction countermeasure device When the countermeasure device detects that the voltage, frequency, phase difference, etc. on the system side and the generator side do not satisfy the setting conditions when the voltage is restored, first, the instantaneous voltage drop countermeasure device issues an opening command to the generator side circuit breaker. To generate a voltage drop in the section between the countermeasure device and the circuit breaker, detect the voltage drop in the countermeasure device, and turn on the semiconductor switch of the countermeasure device to load the section from the system side. Supply power, then Then, the instantaneous voltage drop countermeasure device issues a synchronous closing command to the automatic synchronous closing device provided in the generator-side circuit breaker, and the generator output is controlled to generate power from the automatic synchronous closing device when the set condition is reached. This is to return the original interconnection operation by issuing a closing command to the machine side circuit breaker.

[0013]

EXAMPLE An example of the present invention will be described with reference to FIG. In the figure, the same components as those shown in FIG. 2 of the related art are designated by the same reference numerals and their duplicate description will be omitted.

In FIG. 1, RY ₃ and RY ₄ are protective relays for protecting the generators G ₁ and G ₂ , SY ₃ and SY ₄ are automatic cycle inserting devices for the generators G ₁ and G ₂ , and relay RY ₃ is Section A ₂
Voltage V ₂ , voltage V ₃ in section A ₃ and current I ₃ are input, and an accident is discriminated based on these signals, and the circuit breaker 52G is used as necessary.
Trip ₁ Further, each of the signals V ₂ , V ₃ and I ₃ is R
It is also input to the automatic insertion device SY ₃ through Y _3. Relay R
Y ₄ is a voltage V ₂ of the section A _2, voltage V ₄ of the section A _4, as input current I _4, trip the circuit breaker 52G ₂ according to the need determined accident on the basis of these signals. In addition, V ₂ , V ₄ ,
Each signal of I ₄ is also input to the automatic input device SY ₄ .

The sequence circuit 3 of the instantaneous voltage drop countermeasure device 1 uses the automatic closing device S based on the switching information of the interconnection breaker 52B and the disconnecting switches DS ₁ and DS _{2 and} the information from the detection / control circuit.
Start operation of Y ₃ and SY ₄ , or breakers 52G ₁ and 52G ₂
Is turned on and off.

Other configurations are the same as those of the conventional interconnection breaker 52B.
The circuit is the same as that of the conventional circuit shown in FIG. 2 except that the automatic synchronizing device of FIG.

Next, referring to FIG. 1, a method for re-inserting the instantaneous voltage reduction countermeasure device (hereinafter simply referred to as countermeasure device 1) will be described.

Now, it is assumed that an instantaneous voltage drop occurs on the power system side and the semiconductor switch TS of the countermeasure device 1 is instantly turned off, and then the system voltage is recovered. At this time, setting conditions such as voltage, frequency and phase difference between the system side and the generator side, for example,
Voltage difference ± 10%, frequency difference ± 1%, phase difference ± 10 deg
If it is within the range, the ON command is output from the detection / control circuit 2 and the semiconductor switch TS is reclosed. (The above is the same as the operation of the conventional device).

However, when the above setting conditions are not satisfied (for example, the situation occurs when the output settings of the generators G ₁ and G ₂ and the capacities of the loads L ₃ and L ₄ are significantly different), the countermeasure device 1 Sequencer 3 to circuit breakers 52G ₁ and 52G ₂
Issue a release command to. Since there is no electricity in the section A _{2 in} which both the circuit breakers 52G ₁ and 52G ₂ are open, the voltage V ₂ rapidly increases.
A drop occurs.

Since the detection / control circuit 2 has an instantaneous voltage drop detection circuit for detecting the voltage drop of the voltage V ₂ within a few ms, the semiconductor switch TS detects the instantaneous voltage drop of the voltage V ₂ and the semiconductor switch TS. Power is supplied to the loads L ₃ and L ₄ from the system side.

The detection / control circuit 2 detects this power supply, issues a synchronization input command from the sequence circuit 3 to the automatic synchronization input devices SY ₃ and SY ₄ , controls the outputs of the generators G ₁ and G ₂ , and turns it on. When the condition is reached, the automatic synchronizing device SY ₃ , S
A closing command is issued from Y ₄ to the circuit breakers 52G ₁ and 52G ₂ , and the operating state in which the original system is connected is restored.

According to the above embodiment, the generator side circuit breaker 52
Although the voltage drop occurs in the section A ₂ until the semiconductor switch TS is closed after G ₁ and 52 G ₂ are opened, the instantaneous voltage drop countermeasure device 1 reduces the voltage V ₂ within half a cycle. Since it is possible to detect and turn on the semiconductor switch TS (see the conventional example), the loads L ₃ and L ₄ subject to countermeasures are not affected.

If a voltage drop occurs due to an accident on the system side again after the semiconductor switch TS is turned on and before the generator-side circuit breakers 52G ₁ and 52G ₂ are synchronously thrown, detection and control are performed. The circuit 2 instantaneously detects a decrease in the system side voltage V ₃ , shuts off the semiconductor switch TS, and the sequence circuit 3 bypasses the automatic synchronization closing device to break the circuit breaker 52.
It is possible to deal with this by giving a re-injection command to G ₁ and 52 G ₂ and re-injecting it.

In this case, the voltage may be interrupted for at least about 0.1 second, and some influence on the load may be unavoidable, but it is unlikely that an accident will continue to occur at such timing. So there is no problem.

[0025]

The present invention has the following effects because the method for reincorporating the instantaneous voltage drop countermeasure device is configured as described above.

(1) Even when the automatic synchronizing device is attached to the circuit breaker on the generator side, the automatic synchronizing device can be used to restore the system operating state without affecting the load.

(2) Even after a voltage drop occurs on the system side again after the semiconductor switch is turned on and before the generator side circuit breaker is turned on synchronously, the circuit breaker can be turned on again without affecting the load. it can.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional example.

[Explanation of symbols]

1 ... instantaneous voltage decrease countermeasure device 2 ... detection and control circuit 3 ... sequence circuit 4 ... gate drive circuit 5 ... operation and display circuit 6 ... power waveform recording monitor TS ... semiconductor switch DS _1, DS ₂ ... disconnector 52B ... interconnection (busbar) breakers G _1, G ₂ ... generator 52G _1, 52G ₂ ... generator-side breaker RY ₁ ~RY ₄ ... protection relay SY ₁ to SY ₄ ... automatic synchronization throwing device 52R ... receiving-side shut-off vessel CB ₁ to CB ₄ ... load side circuit breaker A ₁ to A ₄ ... sections (A ₁ ... mains bus, A ₂ ... generator-side bus) L ₁ ~L ₄ ... load

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yasunobu Yanagisawa 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Inside the Meidensha Co., Ltd.

Claims (1)

[Claims] 1. A power system side and an in-house power generation facility side are interconnected by a series circuit of an interconnection breaker and a semiconductor switch of an instantaneous voltage drop countermeasure device, and an automatic synchronization closing device is provided on the generator side breaker. In the existing system, when the system voltage recovers after the operation of the semiconductor switch of the instantaneous voltage drop countermeasure device due to the instantaneous voltage drop, the voltage, frequency, phase difference, etc. on the system side and the generator side satisfy the set conditions. When it is detected that the instantaneous voltage drop countermeasure device does not satisfy the setting condition, the countermeasure device issues an opening command to the generator-side circuit breaker, and the countermeasure device and the circuit breaker. A voltage drop is generated in a section between and, the countermeasure device detects this voltage drop, turns on the semiconductor switch of the countermeasure device, and supplies power to the load in the section from the system side, and then the countermeasure is taken. Synchronous input command from device To the automatic synchronous closing device, and when the output of the generator is controlled to reach the setting condition, the automatic synchronous closing device issues a closing command to the generator side circuit breaker to restore the original interconnection operation. A method for reincorporating an instantaneous voltage drop countermeasure device characterized by the above.