JP3635842B2 - Industrial power plant load shedding device - Google Patents

Industrial power plant load shedding device Download PDF

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JP3635842B2
JP3635842B2 JP04307297A JP4307297A JP3635842B2 JP 3635842 B2 JP3635842 B2 JP 3635842B2 JP 04307297 A JP04307297 A JP 04307297A JP 4307297 A JP4307297 A JP 4307297A JP 3635842 B2 JP3635842 B2 JP 3635842B2
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frequency
detection circuit
load
circuit
power plant
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JPH10243560A (en
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俊久 舟橋
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Meidensha Corp
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Meidensha Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems
    • Y04S20/222—Demand response systems, e.g. load shedding, peak shaving

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Description

【０００１】
【発明の属する技術分野】
この発明は、自家用発電機を電源とし電力会社の電力系統と連系された産業用発電プラントにおいて、一部の電源が脱落した場合、プラント全体が事故停止とならないように、一部の負荷を遮断する負荷遮断装置に関するものである。
【０００２】
【従来の技術】
図３に示す電力系統Ａと連系する発電プラントＢにおいて、自家用発電機Ｇ１の脱落又は受電変圧器Ｔの脱落など事故があった場合、発電機Ｇ２又はＧ１，Ｇが過負荷となり、発電プラントの母線電圧の周波数ｆが低下する。
【０００３】
そのため、母線電圧の周波数を検出し、周波数が予め定めた設定値以下になった場合、予め定めた負荷（例えば、電動機負荷Ｍ３）を遮断し発電量と負荷を平衡させることにより、更なる周波数低下を防ぎ、発電プラント全体停止という最悪事態を招かないようにしている。
【０００４】
図４に従来の６０Ｈｚ発電プラントの負荷遮断シーケンス例を示す。１は母線電圧の周波数を検出する周波数検出器、２は検出した周波数ｆと周波数設定値５９．０Ｈｚを比較し、ｆ＜５９．０ＨｚでＣＢ７のトリップ信号を出力する周波数低下検出回路、３は検出した周波数ｆと周波数設定値５８．５Ｈｚを比較し、ｆ＜５８．５ＨｚでＣＢ６のトリップ信号を出力する周波数低下検出回路である。
【０００５】
例えば、遮断器ＣＢ１又はＣＢ２が開かれ、変圧器Ｔが脱落すると、図５に示すように脱落時点ｔ1から周波数ｆが低下する。時間ｔ2でｆ＝５９．０Ｈｚとなり遮断器ＣＢ７により電動機負荷Ｍ３が遮断され、発電量と負荷との不平衡が解消され、周波数ｆは実線ａのように６０Ｈｚに回復する。しかし、上記負荷遮断が行われないと周波数ｆは点線ｂのように低下し続ける。
【０００６】
【発明が解決しようとする課題】
脱落が発電機Ｇ１又はＧ２の場合、その時の発電量と負荷の状態によっては負荷遮断をしなくても図６の点線ｃに示すように周波数が回復する場合かある。これは脱落せずに残った電源の中に、電力会社の系統があり、その容量が発電機Ｇ１，Ｇ２に比べて一般に極めて大であることから、負荷（電動機）の周波数低下は短時間（ｔ＝ｔ3まで）で押えられるためである。
【０００７】
この場合、負荷遮断の必要がないにも拘らず、周波数ｆがｆ＝５９Ｈｚ（ｔ＝ｔ2）で電動機負荷Ｍ３が遮断されてしまうことになる。
【０００８】
この発明は、このような発電機脱落時における不要な負荷遮断を無くすことができる産業用発電プラントの負荷遮断装置を提供することにある。
【０００９】
【課題を解決するための手段】
この発明は、電力系統と連系運転する産業用発電プラントの周波数低下を回復させるための負荷遮断装置において、
母線電圧の周波数が設定値以下となったことを検出する周波数低下検出回路と、電力系統との連系が断したことを検出する連系断検出回路と、連系断が検出されていることを条件に周波数低下検出回路が出力したとき所定の負荷を遮断する回路と、周波数低下検出回路の出力が所定時間断続していることを確認して所定の負荷を遮断する回路とを有することを特徴とする。
【００１０】
または、電力系統と連系運転する産業用発電プラントの周波数低下を回復させるための負荷遮断装置において、
母線電圧の周波数が第１の設定値以下となったことを検出する第１の周波数低下検出回路と、母線電圧の周波数が前記第１の設定値より低い第２の設定値以下となったことを検出する第２の周波数低下検出回路と、電力系統との連系が断したことを検出する連系断検出回路と、連系断が検出されていることを条件に第１の周波数低下検出回路が出力したとき所定の負荷を遮断する回路と、連系断が検出されていないことを条件に第２の周波数低下検出回路が出力したとき所定の負荷を遮断する回路とを有することを特徴とするものである。
【００１１】
【発明の実施の形態】
実施の形態１
図１に実施の形態１にかかる負荷遮断シーケンス回路を示す。同図において、１は図３の発電プラントＢの母線電圧の周波数ｆを検出する周波数検出器、２は検出周波数ｆを設定周波数５９．０Ｈｚと比較し、ｆ＜５９．０Ｈｚで出力する周波数低下検出回路、４は検出周波数ｆを設定周波数５８．５Ｈｚと比較し、ｆ＜５８．５Ｈｚで出力する周波数低下検出回路、６は受電変圧器Ｔの１次側遮断器ＣＢ１と２次側遮断器ＣＢ２の開閉条件を取り込みどちらかが開である場合に出力する連系断（変圧器脱落）検出回路。
【００１２】
Ｔ１及びＴ２はそれぞれ周波数低下検出回路２及び４の出力を確認して遮断器ＣＢ７及びＣＢ６のトリップ出力するタイマ。
【００１３】
ＡＮＤ１及びＡＮＤ３はそれぞれ連系断検出回路６の出力があることを条件に周波数低下検出回路２及び４の出力を遮断器ＣＢ１及びＣＢ２のトリップ信号として出力する論理積回路である。
【００１４】
以上のように構成されているので、発電プラントＢの遮断器ＣＢ１又はＣＢ２が開いて電力系統ＡＮＤと発電プラントＢの連系が断となった場合、連系断検出回路６が論理積回路ＡＮＤ１及びＡＮＤ３に出力すると共に、発電プラントＢが過負荷となり母線電圧の周波数ｆが低下する。周波数ｆが５９．０Ｈｚまで低下すると周波数低下検出回路２が出力し、論理積回路ＡＮＤ１から遮断器ＣＢ７のトリップ信号が出力するので、遮断器ＣＢ７により電動機負荷Ｍ３が速やかに遮断される。
【００１５】
更に周波数が５９．０Ｈｚまで低下すると周波数低下検出回路４が出力し、論理積回路ＡＮＤ３から遮断器ＣＢ６のトリップ信号が出力するので、遮断器ＣＢ６により電動機負荷Ｍ２も速やかに遮断される。
【００１６】
また、電力系統Ａと発電プラントＢの連系中に、発電プラントＢの発電機Ｇ１が脱落した場合、連系遮断検出回路６が出力しないので、発電機Ｇ１の脱落により発電プラントの母線電圧の周波数ｆが低下し周波数低下検出回路２又は４が出力しても論理積回路ＡＮＤ１又はＡＮＤ２は出力しないので、ＡＮＤ１又はＡＮＤ２の回路により遮断器ＣＢ７又はＣＢ６がトリップされることはない。
【００１７】
周波数ｆが５９．０Ｈｚ以下に低下して周波数低下検出回路２の出力が予め設定されたタイマＴ１の確認時間以上続くと、タイマＴ１が出力して遮断器７をトリップさせ電動機負荷Ｍ３を遮断する。更に周波数ｆが５８．０Ｈｚ以下に低下して周波数低下検出回路４の出力が予め設定されたタイマＴ２の確認時間以上続くと、タイマＴ２が出力して遮断器６をトリップさせ、電動機負荷Ｍ２も遮断する。
【００１８】
周波数ｆが５９．０Ｈｚ又は５８．５Ｈｚ以下に低下して周波数低下検出回路２又は４が出力しても発電プラントＢが電力系統Ａと連系していることによりタイマＴ１又はＴ２の確認時間以内に周波数ｆが回復した場合にはタイマＴ１又はＴ２が出力しないので、電動機Ｍ３又はＭ２が不要遮断されることはない。
【００１９】
以上のように、実施の形態１によれば、発電プラントが電力系統と連系していない場合の周波数低下に対しては、速やかに負荷遮断を行うことでプラントの安定運転を図ることができ、連系している場合の周波数低下に対しては、予め設定したタイマの確認時間を満たした周波数低下の場合に負荷遮断を行い、そうでない場合は極力負荷遮断を行わずにプラントの安定運転を図ることができる。
【００２０】
実施の形態２
図２に実施の形態２にかかる負荷遮断シーケンス回路を示す。同図において、１は図３の発電プラントＢの母線電圧の周波数ｆを検出する周波数検出器、２〜５はそれぞれ、周波数ｆを設定周波数５９．０Ｈｚと、５８．７５Ｈｚ，５８．５Ｈｚ，５８．２５Ｈｚ比較し、周波数ｆが設定周波数以下に低下したことを検出する周波数低下検出回路、６は受電変圧器Ｔの１次側遮断器ＣＢ１と２次側遮断器ＣＢ２の開閉条件を取り込みどちらかが開である場合に出力する連系断（変圧器脱落）検出回路。
【００２１】
ＡＮＤ１及びＡＮＤ３はそれぞれ連系遮断検出回路６の出力があることを条件に周波数低下検出回路２及び４の出力が入力すると遮断器ＣＢ７及びＣＢ６のトリップ信号を出力する論理積回路、ＡＮＤ２及びＡＮＤ４はそれぞれ連系遮断器検出回路６の出力がないことを条件に周波数低下検出回路３及び５の出力が入力すると遮断器ＣＢ７及びＣＢ６のトリップ信号を出力する入力の一方に歪定子のついた論理積回路である。
【００２２】
以上のように構成されているので、図３の遮断器ＣＢ１又はＣＢ２が開となり、電力系統Ａと発電プラントＢの連系が遮断されると連系断検出回路６が出力する。連系断により発電プラントＢが過負荷となり、母線電圧の周波数ｆがｆ＜５９．０Ｈｚ以下に低下すると、周波数低下検出回路２が出力し、論理積回路ＡＮＤ１から遮断器ＣＢ７のトリップ信号を出力するので、ＣＢ７により電動機負荷Ｍ３は速やかに遮断される。周波数ｆが更に低下しｆ＜５８．５Ｈｚになると周波数低下検出回路４が出力し、論理積回路ＡＮＤ３から遮断器ＣＢ６のトリップ信号が出力するので、ＣＢ６により電動機負荷Ｍ２も速やかに遮断される。
【００２３】
上記電動機負荷Ｍ３の遮断又は電動機負荷Ｍ３及びＭ２の遮断により周波数ｆは回復する。
【００２４】
また、電力系統Ａと発電プラントＢの連系中は連系遮断検出回路６の出力はないので、論理積回路ＡＮＤ１及びＡＮＤ３から出力はでない。この連系中に発電機Ｇ１が脱落し、発電プラントＢの母線電圧の周波数ｆがｆ＜５８．７５Ｈｚまで低下すると周波数低下検出回路３が出力し、論理積回路ＡＮＤ２から遮断器ＣＢ７のトリップ信号が出力し、ＣＢ７により電動機負荷Ｍ３が遮断される。
【００２５】
電動機負荷Ｍ３の遮断後、更に周波数ｆがｆ＜５８．２５Ｈｚに低下すると周波数低下検出回路５が出力し、論理積回路ＡＮＤ４から遮断器ＣＢ６のトリップ信号が出力し、ＣＢ６により電動機負荷Ｍ２も遮断される。
【００２６】
以上のように、連系中は周波数ｆが５８．７５Ｈｚ又は５８．２５Ｈｚまで低下しないと電動機負荷Ｍ３又はＭ３とＭ２は遮断とならないので、連系中の発電機脱落時の不要遮断を無くすことができる。
【００２７】
【発明の効果】
この発明は、上述のとおり、電力系統と発電プラントとの連系の有無を検出し、負荷遮断のタイミング又は周波設定値を変えて負荷遮断をするので、不要な負荷遮断を行わずに安定運転を行うことが可能となる。
【図面の簡単な説明】
【図１】実施の形態１にかかる負荷遮断シーケンス回路図。
【図２】実施の形態２にかかる負荷遮断シーケンス回路図。
【図３】産業用発電プラントの構成説明図。
【図４】従来例にかかる負荷遮断シーケンス回路図。
【図５】受電変圧器脱落時の周波数変化を示すグラフ。
【図６】発電機脱落時の周波数変化を示すグラフ。
【符号の説明】
１…周波数低下検出回路
２〜５…周波数低下検出回路
６…連系断検出回路（変圧器脱落検出回路）
Ａ…電力系統
Ｂ…発電プラント
ＣＢ…遮断器
ｆ…周波数
Ｇ…自家用発電機
Ｌ…電灯など一般負荷
Ｍ…電動機負荷
Ｔ…変圧器
Ｕ…電力会社の変電所（系統電源）。[0001]
BACKGROUND OF THE INVENTION
In an industrial power plant that uses a private generator as a power source and is connected to the power system of an electric power company, if a part of the power source is dropped, a part of the load is prevented so that the entire plant does not stop accidentally. The present invention relates to a load interrupt device for interrupting.
[0002]
[Prior art]
In the power plant B connected to the power system A shown in FIG. 3, if there is an accident such as a drop of the private generator G1 or a drop of the power receiving transformer T, the generator G2 or G1, G is overloaded, and the power plant The frequency f of the bus voltage decreases.
[0003]
Therefore, if the frequency of the bus voltage is detected, and the frequency is equal to or lower than a predetermined set value, a predetermined load (for example, the motor load M3) is cut off and the power generation amount and the load are balanced to further increase the frequency. It prevents the decline and prevents the worst situation of the entire power plant shutting down.
[0004]
FIG. 4 shows an example of a load interruption sequence of a conventional 60 Hz power plant. 1 is a frequency detector that detects the frequency of the bus voltage, 2 is a frequency drop detection circuit that compares the detected frequency f with a frequency setting value of 59.0 Hz, and outputs a trip signal of CB7 at f <59.0 Hz. This is a frequency drop detection circuit that compares a detected frequency f with a frequency setting value 58.5 Hz and outputs a trip signal of CB6 at f <58.5 Hz.
[0005]
For example, breaker CB1 or CB2 is opened and the transformer T is falling, the frequency f is lowered from the falling time t 1 as shown in FIG. At time t 2 , f = 59.0 Hz, and the motor load M3 is cut off by the circuit breaker CB7, the unbalance between the power generation amount and the load is eliminated, and the frequency f is restored to 60 Hz as indicated by the solid line a. However, if the load is not interrupted, the frequency f continues to decrease as indicated by the dotted line b.
[0006]
[Problems to be solved by the invention]
When the dropout is the generator G1 or G2, depending on the amount of power generation and the state of the load at that time, the frequency may be recovered as shown by the dotted line c in FIG. 6 without interrupting the load. This is because there is a power company system among the power sources remaining without dropping, and the capacity thereof is generally much larger than that of the generators G1 and G2, so the frequency reduction of the load (motor) is short ( This is because for pressing up t = t 3).
[0007]
In this case, the motor load M3 is cut off when the frequency f is f = 59 Hz (t = t 2 ) even though it is not necessary to cut off the load.
[0008]
An object of the present invention is to provide an industrial power plant load shedding device that can eliminate unnecessary load shedding when the generator is dropped.
[0009]
[Means for Solving the Problems]
The present invention relates to a load shedding device for recovering a frequency drop of an industrial power plant that is connected to an electric power system.
A frequency drop detection circuit that detects that the frequency of the bus voltage is lower than the set value, a connection disconnection detection circuit that detects that the power system is disconnected, and a connection disconnection is detected. And a circuit that shuts off a predetermined load when the frequency drop detection circuit outputs, and a circuit that cuts off the predetermined load after confirming that the output of the frequency drop detection circuit is intermittent for a predetermined time. Features.
[0010]
Or, in a load shedding device for recovering the frequency drop of an industrial power plant that is connected to the power system,
A first frequency drop detection circuit for detecting that the frequency of the bus voltage is equal to or lower than a first set value; and the frequency of the bus voltage is equal to or lower than a second set value lower than the first set value. A second frequency drop detection circuit that detects the disconnection, a connection disconnection detection circuit that detects that the connection with the power system has been disconnected, and a first frequency decrease detection on condition that the connection disconnection is detected. A circuit that cuts off the predetermined load when the circuit outputs, and a circuit that cuts off the predetermined load when the second frequency drop detection circuit outputs on condition that no interconnection disconnection is detected. It is what.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
FIG. 1 shows a load cutoff sequence circuit according to the first exemplary embodiment. In the figure, 1 is a frequency detector that detects the frequency f of the bus voltage of the power plant B in FIG. 3, 2 is a frequency drop that compares the detected frequency f with the set frequency 59.0 Hz, and outputs at f <59.0 Hz The detection circuit 4 compares the detection frequency f with the set frequency 58.5 Hz, and outputs a frequency drop detection circuit that outputs f <58.5 Hz. 6 is the primary side circuit breaker CB1 and the secondary side circuit breaker of the receiving transformer T. A disconnection (transformer dropout) detection circuit that captures the open / close conditions of CB2 and outputs when either is open.
[0012]
T1 and T2 are timers that check the outputs of the frequency drop detection circuits 2 and 4 and output trips of the circuit breakers CB7 and CB6, respectively.
[0013]
AND1 and AND3 are AND circuits that output the outputs of the frequency drop detection circuits 2 and 4 as trip signals of the circuit breakers CB1 and CB2, respectively, on condition that the output of the disconnection detection circuit 6 is present.
[0014]
Since it is configured as described above, when the circuit breaker CB1 or CB2 of the power plant B is opened and the power system AND and the power plant B are disconnected, the connection disconnection detection circuit 6 is connected to the AND circuit AND1. And output to AND3, the power plant B becomes overloaded and the frequency f of the bus voltage decreases. When the frequency f drops to 59.0 Hz, the frequency drop detection circuit 2 outputs and the trip signal of the circuit breaker CB7 is output from the AND circuit AND1, so the motor load M3 is quickly cut off by the circuit breaker CB7.
[0015]
When the frequency further decreases to 59.0 Hz, the frequency decrease detection circuit 4 outputs and the trip signal of the circuit breaker CB6 is output from the AND circuit AND3. Therefore, the motor load M2 is also quickly disconnected by the circuit breaker CB6.
[0016]
In addition, when the generator G1 of the power plant B is disconnected during the connection between the power system A and the power plant B, the connection disconnection detection circuit 6 does not output. Since the AND circuit AND1 or AND2 does not output even if the frequency f decreases and the frequency decrease detection circuit 2 or 4 outputs, the circuit breaker CB7 or CB6 is not tripped by the AND1 or AND2 circuit.
[0017]
When the frequency f drops below 59.0 Hz and the output of the frequency drop detection circuit 2 continues for a preset time of the timer T1, the timer T1 outputs and trips the circuit breaker 7 to cut off the motor load M3. . Further, when the frequency f is decreased to 58.0 Hz or less and the output of the frequency decrease detection circuit 4 continues for a preset confirmation time of the timer T2, the timer T2 outputs to trip the circuit breaker 6, and the motor load M2 also Cut off.
[0018]
Even if the frequency f drops below 59.0 Hz or 58.5 Hz and the frequency drop detection circuit 2 or 4 outputs, the power plant B is connected to the power system A, so that the timer T1 or T2 is within the confirmation time. When the frequency f is recovered, the timer T1 or T2 is not output, so that the motor M3 or M2 is not unnecessarily shut off.
[0019]
As described above, according to the first embodiment, the stable operation of the plant can be achieved by quickly shutting off the load against the frequency reduction when the power plant is not connected to the power system. For frequency reduction when connected, the load is shut off when the frequency falls below the preset timer confirmation time, otherwise the stable operation of the plant is performed without performing load cutoff as much as possible. Can be achieved.
[0020]
Embodiment 2
FIG. 2 shows a load cutoff sequence circuit according to the second exemplary embodiment. In the figure, 1 is a frequency detector for detecting the frequency f of the bus voltage of the power plant B in FIG. 3, and 2 to 5 are frequency f set frequencies 59.0 Hz, 58.75 Hz, 58.5 Hz, 58, respectively. .25Hz comparison, frequency drop detection circuit for detecting that frequency f has fallen below the set frequency, 6 takes in the switching condition of primary circuit breaker CB1 and secondary circuit breaker CB2 of receiving transformer T Disconnection (transformer dropout) detection circuit that outputs when is open.
[0021]
AND1 and AND3 are AND circuits that output trip signals of the circuit breakers CB7 and CB6 when the outputs of the frequency drop detection circuits 2 and 4 are input on condition that there is an output of the connection interruption detection circuit 6, respectively. AND2 and AND4 When the outputs of the frequency drop detection circuits 3 and 5 are input on the condition that there is no output of the interconnection breaker detection circuit 6, respectively, a logical product having a distortion constant on one of the inputs for outputting the trip signals of the circuit breakers CB7 and CB6. Circuit.
[0022]
Since the circuit breaker CB1 or CB2 in FIG. 3 is opened and the connection between the power system A and the power plant B is disconnected, the connection disconnection detection circuit 6 outputs. When the power plant B is overloaded by disconnection and the frequency f of the bus voltage drops below f <59.0 Hz, the frequency drop detection circuit 2 outputs and outputs the trip signal of the circuit breaker CB7 from the AND circuit AND1. Therefore, the motor load M3 is quickly cut off by the CB7. When the frequency f further decreases and f <58.5 Hz, the frequency decrease detection circuit 4 outputs, and the trip signal of the circuit breaker CB6 is output from the AND circuit AND3. Therefore, the motor load M2 is also quickly disconnected by the CB6.
[0023]
The frequency f is recovered by the interruption of the motor load M3 or the interruption of the motor loads M3 and M2.
[0024]
Further, during the connection between the electric power system A and the power plant B, there is no output from the connection interruption detection circuit 6, and therefore no output from the AND circuits AND1 and AND3. When the generator G1 is dropped during this interconnection and the frequency f of the bus voltage of the power plant B drops to f <58.75 Hz, the frequency drop detection circuit 3 outputs the trip signal of the circuit breaker CB7 from the AND circuit AND2. Is output, and the motor load M3 is cut off by the CB7.
[0025]
When the frequency f further drops to f <58.25 Hz after the motor load M3 is cut off, the frequency drop detection circuit 5 outputs, and the trip signal of the circuit breaker CB6 is outputted from the AND circuit AND4, and the motor load M2 is also cut off by CB6. Is done.
[0026]
As described above, since the motor load M3 or M3 and M2 is not cut off unless the frequency f is reduced to 58.75 Hz or 58.25 Hz during interconnection, unnecessary interruption when the generator is dropped during interconnection is eliminated. Can do.
[0027]
【The invention's effect】
As described above, the present invention detects the presence / absence of interconnection between the power system and the power plant, and cuts off the load by changing the load breaking timing or frequency setting value, so stable operation without unnecessary load breaking is performed. Can be performed.
[Brief description of the drawings]
FIG. 1 is a load cutoff sequence circuit diagram according to a first embodiment;
FIG. 2 is a load cutoff sequence circuit diagram according to the second embodiment;
FIG. 3 is a diagram illustrating the configuration of an industrial power plant.
FIG. 4 is a load cutoff sequence circuit diagram according to a conventional example.
FIG. 5 is a graph showing a change in frequency when the receiving transformer is dropped.
FIG. 6 is a graph showing a change in frequency when the generator is dropped.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Frequency drop detection circuit 2-5 ... Frequency drop detection circuit 6 ... Connection disconnection detection circuit (transformer drop detection circuit)
A ... Power system B ... Power generation plant CB ... Circuit breaker f ... Frequency G ... Private generator L ... General load M such as an electric lamp M ... Motor load T ... Transformer U ... Power company substation (system power supply).

Claims (2)

電力系統と連系運転する産業用発電プラントの周波数低下を回復させるための負荷遮断装置において、
母線電圧の周波数が設定値以下となったことを検出する周波数低下検出回路と、
電力系統との連系が断したことを検出する連系断検出回路と、
連系断が検出されていることを条件に周波数低下検出回路が出力したとき所定の負荷を遮断する回路と、
周波数低下検出回路の出力が所定時間断続していることを確認して所定の負荷を遮断する回路と、
を有することを特徴とする産業用発電プラントの負荷遮断装置。In the load shedding device for recovering the frequency drop of the industrial power plant that is connected to the power system,
A frequency drop detection circuit for detecting that the frequency of the bus voltage is equal to or lower than a set value;
An interconnection disconnection detection circuit for detecting that the interconnection with the power system is disconnected;
A circuit that cuts off a predetermined load when the frequency drop detection circuit outputs on condition that a disconnection is detected;
A circuit for confirming that the output of the frequency drop detection circuit is intermittent for a predetermined time and blocking a predetermined load;
A load shut-off device for an industrial power plant characterized by comprising: 電力系統と連系運転する産業用発電プラントの周波数低下を回復させるための負荷遮断装置において、
母線電圧の周波数が第１の設定値以下となったことを検出する第１の周波数低下検出回路と、
母線電圧の周波数が前記第１の設定値より低い第２の設定値以下となったことを検出する第２の周波数低下検出回路と、
電力系統との連系が断したことを検出する連系断検出回路と、
連系断が検出されていることを条件に第１の周波数低下検出回路が出力したとき所定の負荷を遮断する回路と、
連系断が検出されていないことを条件に第２の周波数低下検出回路が出力したとき所定の負荷を遮断する回路と、
を有することを特徴とする産業用発電プラントの負荷遮断装置。In the load shedding device for recovering the frequency drop of the industrial power plant that is connected to the power system,
A first frequency drop detection circuit for detecting that the frequency of the bus voltage is equal to or lower than a first set value;
A second frequency drop detection circuit for detecting that the frequency of the bus voltage is equal to or lower than a second set value lower than the first set value;
An interconnection disconnection detection circuit for detecting that the interconnection with the power system is disconnected;
A circuit that shuts off a predetermined load when the first frequency drop detection circuit outputs on condition that a disconnection is detected;
A circuit that shuts off a predetermined load when the second frequency drop detection circuit outputs on condition that no interconnection disconnection is detected;
A load shut-off device for an industrial power plant characterized by comprising:
JP04307297A 1997-02-27 1997-02-27 Industrial power plant load shedding device Expired - Fee Related JP3635842B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP04307297A JP3635842B2 (en) 1997-02-27 1997-02-27 Industrial power plant load shedding device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP04307297A JP3635842B2 (en) 1997-02-27 1997-02-27 Industrial power plant load shedding device

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JPH10243560A JPH10243560A (en) 1998-09-11
JP3635842B2 true JP3635842B2 (en) 2005-04-06

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Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5193341A (en) * 1975-02-12 1976-08-16
JPS5780229A (en) * 1980-11-07 1982-05-19 Nippon Kokan Kk Power system paralleler off detector for waste heat turbine generator
JPS609333A (en) * 1983-06-24 1985-01-18 住友金属工業株式会社 Method of protecting power system
JPH04275029A (en) * 1991-02-28 1992-09-30 Kawasaki Steel Corp Load interrupting device at time of parallel off fault

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