JP3288797B2 - Instantaneous voltage drop countermeasure device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is, as in the cogeneration system, the substation power system and private power generation equipment is operating interconnection, using a semiconductor switch in the busbar breakers, instantly upon mains failure In particular, the present invention relates to an instantaneous voltage drop countermeasure device for disconnecting the power system from the power system to minimize the instantaneous voltage drop of the generator and to prevent the generator from collapsing due to overload.

[0002]

Conventionally, co-generation system as shown in FIG. 5, the power system side bus B _1, private power generation equipment-side bus B ₂
Connecting the door with Haharen (busbar) breakers 52B _1, at the time of the electric power system side fault shut off the mother communicating breaker 52B _1, it becomes important load L ₃ ~L ₅ to the power supply is possible circuit configuration of the demand wife ing.

[0003] Vacuum circuit breaker as a base communicating breaker 52B ₁ (V
The shut-off time when using CB) requires about 0.3 seconds as follows.

[0004] Private power generator A when power system goes out or voltage drops momentarily
G is up to about mother communicating breaker 52B ₁ trips 0.
3 seconds, the load that interconnection full load L ₁ ~L ₅ as well power system of consumers becomes to bear, becomes overloaded.

[0005] Current cogeneration for private power generator, when selecting blocking load, important load L ₃ ~L ₅ 80%, other loads L _1, L ₂ 20%, the interruption time of 52B ₁ Mother communicated breaker under the condition of 0.3 seconds to 0.5 seconds, when the power mains failure (overload 400% assumed), so that the engine ENG does not stall, the characteristics of the exciter moment of inertia GD ² and generator AG of the drive unit Is generally selected.

[0006]

In the above-mentioned conventional cogeneration system, when the load of the generator AG is selectively cut off when a power failure occurs in the power system under the following conditions, the voltage and rotation speed of the generator are FIG. 6 shows the result of simulating how the power changes.

[0007] (1) Ratings of the power generator 375KVA-4P-6600V-0.8PF-150
0 rpm GD ² AG = 44.0 kg · m ² , GD ² ENG = 48.
0kg ・ m ² (2) Overload time 0.3 seconds (3) Generator load 100% before power failure, 400% at power failure start, after selective cutoff: 8
0% The following can be seen from FIG.

When the load is selectively cut off (after 0.3 seconds), the generator voltage (dotted line) drops to 57%.

That is, the voltage drop of the important loads L _{3 to} L ₅ left after the selective cutoff is 40% or more, the load affected is not small, and some measure for voltage drop is required.

An uninterruptible power supply (CVCF, UPS) is generally used as this countermeasure device, and other specialized countermeasure devices are also commercially available.

As is apparent from the above, when a power failure or an instantaneous power failure occurs in the power system, if the power system side is disconnected at a higher speed, the load on the power generation device can be reduced accordingly. The effect on the load is small.

The present invention has been made on the basis of the results of the above-mentioned simulation. It is an object of the present invention to provide a power generation system such as a cogeneration system which uses a semiconductor switch when a power failure or instantaneous voltage drop occurs. side the Resshi solutions at high speed, the generator minimizes the voltage drop, also pass while preventing the fall together generator due to an overload, the circuit even when the semiconductor switch is unlikely to fail during interconnected operation to provide an instantaneous voltage decrease countermeasure device that enables interconnection luck <br/> rolling the conventional method by switching to.

[0013]

To achieve the above object, the instantaneous voltage drop countermeasure device according to the present invention is configured as follows.

(1) Manual bypass switching system A semiconductor switch and its bypass circuit, and a disconnection for switching this semiconductor switch and the bypass circuit to connect in series with a bus connection breaker between the power system side bus and the private power generation facility side bus. And a container.

(2) Automatic bypass switching system A series circuit composed of a semiconductor switch and a circuit breaker connected in series to a bus communication circuit breaker that connects the power system bus and the bus on the side of the private power generation facility, and bypasses this series circuit. It consists of a bypass circuit breaker.

[0016]

[Function] (1) Manual bypass switching method This is a circuit method in which the use or non-use of a semiconductor switch can be selected by a disconnector. The semiconductor switch is always selected, and a series circuit with a bus connection circuit breaker is connected to the power system side and the private power generation equipment side interconnection luck <br/> rolling. When interconnection power system side during operation is a power failure or brownout, the semiconductor switch detects the voltage drop, turns off the interconnection instantaneously (1 cycle or less). Next, if the instantaneous voltage drop recovers before the mother breaker trips, if the instantaneous voltage drop is restored, the power-on condition (for example, the system generator voltage difference within ± 10%, the frequency difference ± 2
% Within, if within the phase difference ± 20 °) is satisfied, turns on the semiconductor switch, to continue the interconnected operation. If the instantaneous voltage drop is prolonged and the power breaker trips, or if the restart condition is not satisfied, the subsequent synchronous closing is performed by the synchronous closing device of the generator.

[0017] When the semiconductor switch has failed, tripped switch to the bypass circuit side of the disconnecting switch the busbar breaker, the interconnected operation of using the bypass circuit by turning on the busbar breaker synchronous feeding device It becomes possible.

(2) Automatic bypass switching system This is a circuit system in which the use or non-use of a semiconductor switch can be selected by a circuit breaker, and the constant operation is the same as in the above (1).

[0019] When the semiconductor switch has failed, on the bypass breaker, by turning off the semiconductor side breaker, interconnected operation even during failure can continue.

[0020]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a single-line connection diagram showing a cogeneration system, and FIGS. 2 and 3 are single-line connection diagrams showing examples of a bus connecting portion of the cogeneration system.

Embodiment 1 Referring to FIGS. 1 and 2, AG is a private power generator rotated by an engine ENG, B ₁ is a power system side bus connected to the power system via a power receiving circuit breaker 52R, and B ₂ is a power system side bus. connected private power generation side bus to the generator AG via the breaker 52G for private power generation, 52B ₁ bus B ₁ and B master communication (busbar), such as ₂ vacuum interrupter to contact breaker 1 mother communicating breaker 52B ₁ connected in series with the instantaneous voltage decrease countermeasure device.

T ₁ and T ₂ feeder breakers 52L ₁ and 52L ₂
Connected to the bus B ₁ via the trans, T ₃ through T ₅ feeling electrostatic breaker 52L ₃ ~52L ₅ a transformer connected to the bus B ₂ via, L _1, L ₂ is the transformer T _1, loads that are powered from T _2, L ₃ is the most important load powered through a CVCF device from the transformer T _3, L _4, L ₅ is critical loads fed from the transformer T _4, T _5.

The instantaneous voltage drop countermeasure device 1 includes a mother circuit breaker 52.
And B ₁ and the semiconductor switch 52B ₂ within switching time 1 cycle with Fuse connected in series, the mother communicates selectively block the bypass circuit 2 and the semiconductor switch 52B ₂ and the bypass circuit 2 of the semiconductor switch is composed of vessel 52B ₁ and disconnecting switch DS _1, DS ₂ connected in series.

[0025] Normally, disconnector semiconductor switch 52B ₂ D
Selected by S _1, DS _2, operated by interconnection of the power system side and the private power generation system side by a series circuit of breaker 52B ₁ and the semiconductor switch 52B _2.

[0026] a power failure to the power system occurs during the interconnected operation, the voltage of the private power generator AG is lowered. Semiconductor switch 52B ₂ is turned OFF within 1 cycle is detected from the voltage waveform or the like the voltage drop instantaneously.

As described above, since the power system-side bus B ₁ is separated from the private power generation system-side bus B ₂ within one cycle from the occurrence of the sag by the semiconductor switch 52B ₂ , the generator voltage is 73% (FIG. 6). The voltage drop is 27%), which is 16% better than that of the mother circuit breaker 52B ₁ (disconnection time: 0.3 second).

FIG. 4 shows this pattern in FIG. 1-2-3 of Electric Cooperative Research Vol. 46, No. 3, "Measures for Instantaneous Voltage Drop".

[0029] According to FIG. 4, the use of semiconductor switch 52B ₂ of the switching time 20 ms, the influence on the variable speed motor is out, there is no effect on the other load device, it is possible to continue the operation. When the same comparison of the mother communicating breaker 52B ₁ of the (switching time of 0.3 seconds) would be affected to a load device other than the under voltage relay and the electromagnetic switch. The instantaneous voltage drop short, if the voltage before the mother communicating breaker 52B ₁ is tripped have returned to normal, the semiconductor switch 52B ₂
The cycling conditions (e.g., line generator voltage within ± 10%, frequency Within ± 2%, within the phase difference ± 20 °) enough effort is to continue the interconnected operation turned on.

The instantaneous voltage drop prolonged (power failure) if the mother communicating breaker 52B ₁ has tripped, if Mahata reintroduction condition is not satisfied, then the synchronization-up performed by the synchronous feeding device of the generator.

[0031] When the semiconductor switch 52B ₂ is failure trip the mother communicating breaker 52B _1, to remove the interconnected operation. In this case, if the bypass circuit 2 is selected by the disconnecting switches DS ₁ and DS ₂ and the mother circuit breaker 52B ₁ is turned on by the synchronization input device, the power system side by the mother circuit breaker 52B ₁ and the bypass circuit 2 and the private power generation system it is possible to interconnected operation of the side.

Embodiment 2 In FIG. 4, the instantaneous voltage drop countermeasure device 1 is
A series circuit of a 2B ₁ and breaker 52B ₃ for disconnecting the circuit between the semiconductor switch 52B ₂ dated Fuse the semiconductor switches connected in series, the semiconductor switch 52B ₂ and the semiconductor side breaker 52B It consists of a bypass circuit breaker that bypasses the series circuit of ₃ . Usually, the semiconductor switch 52B ₂
It was selected by the semiconductor side breaker 52B _3, operated by interconnection of the power system side and the private power generation system side by a series circuit of the mother communicating breaker 52B ₁ and the semiconductor switch 52B _2.

The operation when the instantaneous voltage drop occurs and the operation when the instantaneous voltage drop recovers are the same as those in the first embodiment.

The semiconductor switch 52B ₂ is is turned bypass breaker 52B ₄ and simultaneously trip the semiconductor side breaker 52B ₃ when a failure to continue the interconnected operation.

Each of the circuit breakers can be a switch such as a vacuum switch. Needless to say, the circuit and the like can be appropriately changed.

[0036]

Since the present invention is configured as described above, the following effects can be obtained.

(1) Measures against instantaneous voltage drop for an important load after selective interruption are reduced.

(2) When an instantaneous voltage drop of the power-side system occurs, high-speed selective cutoff can be performed, so that the output voltage of the generator is less reduced and the reliability of continuation of operation of the power generator is further improved.

(3) Since the overload time to the power generator is shortened by the high-speed selective cutoff, the cost of the power generator can be reduced, for example, an engine having a small moment of inertia (GD ² ) can be used.

(4) Even in the event of a failure of the present apparatus, operation with the conventional system is possible.

[Brief description of the drawings]

FIG. 1 is a single-line connection diagram showing a cogeneration system according to an embodiment.

FIG. 2 is a single-line connection diagram showing a bus connecting portion of the cogeneration system according to the first embodiment.

FIG. 3 is a single-line connection diagram showing a bus connecting portion of the cogeneration system according to the second embodiment.

FIG. 4 is an explanatory diagram showing an example of the effect of an instantaneous voltage drop of a load device.

FIG. 5 is a single-line connection diagram showing a cogeneration system according to a conventional example.

FIG. 6 is a diagram showing electric power, voltage, and rotation speed at the time of an instantaneous overload of the generator.

[Explanation of symbols]

1 ... instantaneous voltage decrease countermeasure device 2 ... bypass circuit 52B ₁ ... busbar (mother communication) circuit breaker (generator synchronous turned breaker) 52B ₄ ... bypass breaker _{52G, 52L 1 ~52L 5, 52R} ... breaker 52B ₂ ... semiconductor switch AG ... generator B _1, B ₂ ... bus DS _1, DS ₂ ... disconnector L ₁ ~L ₅ ... load

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuo Kataoka 2-1-117 Osaki, Shinagawa-ku, Tokyo, Japan Inside the Meidensha Co., Ltd. (72) Inventor Yoshiharu Ogawa 2-1-1, Osaki, Shinagawa-ku, Tokyo, Japan Meidensha Co., Ltd. (72) Inventor Toshiyuki Koguchi 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Inside Meidensha Co., Ltd. (56) References JP-A-63-917 (JP, A) JP-A-2-294237 (JP, A) JP-A-3-218229 (JP, A) JP-A-1-315223 (JP, A) JP-A-62-38033 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02J 3/38

Claims (2)

(57) [Claims] 1. A semiconductor switch comprising a semiconductor switch, a bypass circuit therefor, and a disconnector for switching the semiconductor switch and the bypass circuit to connect in series with a bus communication breaker between the power system side bus and the private power generation facility side bus, power failure or a system of interconnected operation to mains the selected semiconductor switch power system side and the private power generation equipment side by the always disconnector
Instantly Resshi solution to the mains by a semiconductor switch during a momentary voltage drop in the integration side, instantaneously, characterized in that to allow interconnection operation using a bypass circuit in the event of a fault or during inspection of the semiconductor switch Voltage drop prevention device. 2. A series circuit comprising a semiconductor switch and a circuit breaker connected in series to a bus communication circuit breaker for connecting a power system bus and a bus on a private power generation facility side, and a bypass circuit breaker for bypassing the series circuit. becomes, blackout or mains always drove interconnection power system side and the private power generation equipment-side bypass breaker is turned off mains
Resshi solution the mains instantaneously by the semiconductor switch during lowering of the instantaneous voltage, instantaneous voltage drop, characterized in that to allow interconnection operation using a bypass circuit in the event of a fault or during inspection of the semiconductor switch Countermeasure device.