JP5618336B2 - Combined cycle power plant and operation method - Google Patents

Combined cycle power plant and operation method Download PDF

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JP5618336B2
JP5618336B2 JP2012012235A JP2012012235A JP5618336B2 JP 5618336 B2 JP5618336 B2 JP 5618336B2 JP 2012012235 A JP2012012235 A JP 2012012235A JP 2012012235 A JP2012012235 A JP 2012012235A JP 5618336 B2 JP5618336 B2 JP 5618336B2
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岳史 長山
岳史 長山
祐介 眞鍋
祐介 眞鍋
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Mitsubishi Power Ltd
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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
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Description

本発明は、コンバインドサイクル型発電プラントおよび運転方法に関する。   The present invention relates to a combined cycle power plant and an operation method.

従来、コンバインドサイクル型発電プラント（以下、Ｃ／Ｃ発電プラントと称する）は、特許文献１、２に記載されるように、１台の蒸気タービンと、１台以上のガスタービンと、それに付随する補機類（再熱器、蒸気発生器等）を含んで構成される。
そして、Ｃ／Ｃ発電プラントはガスタービンの運転で生じる排熱で発生する蒸気が蒸気タービンに供給されるように構成される。
このようなＣ／Ｃ発電プラントにおいて、ガスタービンを単独負荷運転するときには、再熱器の温度上昇を抑制するために再熱器に戻り蒸気を供給することが必要になる。
特許文献１に開示される多軸型コンバインドサイクルプラント（Ｃ／Ｃ発電プラント）は蒸気タービンの停止時に、高圧タービンバイパス管を介して再熱器に戻り蒸気を流し込んでガスタービンの単独負荷運転を可能とするように構成される。 Conventionally, a combined cycle type power plant (hereinafter referred to as a C / C power plant) includes one steam turbine, one or more gas turbines, and an associated one, as described in Patent Documents 1 and 2. It includes auxiliary equipment (reheater, steam generator, etc.).
The C / C power plant is configured such that steam generated by exhaust heat generated by the operation of the gas turbine is supplied to the steam turbine.
In such a C / C power plant, when the gas turbine is operated with a single load, it is necessary to supply the return steam to the reheater in order to suppress the temperature rise of the reheater.
The multi-shaft combined cycle plant (C / C power generation plant) disclosed in Patent Document 1 performs single load operation of a gas turbine by returning steam to a reheater via a high-pressure turbine bypass pipe when the steam turbine is stopped. Configured to allow.

特開２００４−２７９３８号公報JP 2004-27938 A 特開平９−６８００４号公報JP-A-9-68004

特許文献１に開示される多軸型コンバインドサイクルプラントのように、ガスタービンを単独負荷運転するためには、再熱器に戻り蒸気を流し込むための高圧タービンバイパス管が必要になる。
また、特許文献２に開示されるようにガスタービンの排熱で発生する蒸気が高圧タービンバイパス管（タービンバイパス回路）を介して直接、復水器に流れ込む構成のコンバインドサイクル発電プラントでは、ガスタービンの単独負荷運転時にガスタービンの排熱で発生する蒸気を戻り蒸気として再熱器に戻すことができない。したがって、このように構成されるコンバインドサイクル発電プラントでは、再熱器が耐熱許容値を超えて高温になる場合があるためガスタービンの単独負荷運転は実施されない。 As in the multi-shaft combined cycle plant disclosed in Patent Document 1, in order to operate the gas turbine with a single load, a high-pressure turbine bypass pipe for returning steam to the reheater is required.
Further, as disclosed in Patent Document 2, in a combined cycle power plant in which steam generated by exhaust heat of a gas turbine flows directly into a condenser via a high-pressure turbine bypass pipe (turbine bypass circuit), the gas turbine During the single load operation, the steam generated by the exhaust heat of the gas turbine cannot be returned to the reheater as return steam. Therefore, in the combined cycle power plant configured in this way, the reheater may reach a high temperature exceeding the allowable heat resistance value, so that the single load operation of the gas turbine is not performed.

そこで、本発明は、ガスタービンの排熱で発生する蒸気が再熱器に戻らずに復水器に流れ込む構成であってもガスタービンを単独で運転可能なコンバインドサイクル型発電プラントおよび運転方法を提供することを課題とする。   Therefore, the present invention provides a combined cycle type power plant and an operation method capable of operating a gas turbine independently even if steam generated by exhaust heat of the gas turbine flows into the condenser without returning to the reheater. The issue is to provide.

前記課題を解決するため本発明は、ガスタービンと、前記ガスタービンの排気ガスに含まれる排熱を利用して発生する高圧主蒸気で駆動する高圧タービン、前記排熱を利用して発生する中圧主蒸気で駆動する中圧タービン、および、前記排熱を利用して発生する低圧主蒸気で駆動する低圧タービンを含んでなる蒸気タービンと、前記高圧タービンから排出される前記高圧主蒸気を凝縮して復水を発生する復水器と、前記復水器で発生する前記復水を前記排熱で過熱する排熱回収ボイラと、前記排熱回収ボイラで過熱された前記復水で前記高圧主蒸気を発生する高圧ドラムと、前記高圧ドラムで発生する前記高圧主蒸気を前記高圧タービンをバイパスして前記復水器に導入する高圧タービンバイパス管および当該高圧タービンバイパス管における前記高圧主蒸気の圧力を調節して前記高圧主蒸気を前記復水器へ導入する高圧主蒸気圧力調節手段と、を含んで構成され、前記排熱回収ボイラに、前記高圧ドラムで発生する前記高圧主蒸気を前記排熱で過熱する高圧過熱器と、前記高圧タービンから排気される前記高圧主蒸気を前記排熱で過熱する再熱器と、が、前記排気ガスの流れに対する上流からこの順に配置されるコンバインドサイクル型発電プラントおよびその運転方法とする。そして、前記蒸気タービンが停止したときに、前記高圧ドラムで発生する前記高圧主蒸気を前記高圧タービンバイパス管で前記復水器に導入し、前記高圧主蒸気圧力調節手段で前記高圧主蒸気を減圧することで、当該高圧ドラムの蒸発量を増やして前記高圧過熱器における前記排熱の吸熱量を増やすとともに、前記高圧ドラムの蒸発量が当該高圧ドラムの許容最大蒸発量を超えないように前記高圧タービンバイパス管における前記高圧主蒸気の圧力を調節し、さらに、前記高圧過熱器で吸熱された後の前記排気ガスに含まれる前記排熱で前記再熱器が耐熱許容値を超えて高温にならないように前記ガスタービンの運転負荷を調節して前記ガスタービンを単独で運転可能であること、を特徴とする。   In order to solve the above problems, the present invention relates to a gas turbine, a high-pressure turbine driven by high-pressure main steam generated using exhaust heat contained in the exhaust gas of the gas turbine, and a medium generated using the exhaust heat. A steam turbine comprising an intermediate pressure turbine driven by pressure main steam, a low pressure turbine driven by low pressure main steam generated using the exhaust heat, and the high pressure main steam discharged from the high pressure turbine is condensed The condenser that generates condensate, the exhaust heat recovery boiler that superheats the condensate generated in the condenser with the exhaust heat, and the high pressure in the condensate that is overheated with the exhaust heat recovery boiler A high-pressure drum that generates main steam, a high-pressure turbine bypass pipe that bypasses the high-pressure turbine and introduces the high-pressure main steam generated in the high-pressure drum into the condenser, and the high-pressure turbine bypass pipe High pressure main steam pressure adjusting means for adjusting the pressure of the high pressure main steam and introducing the high pressure main steam into the condenser, and is generated in the exhaust heat recovery boiler by the high pressure drum. A high-pressure superheater that superheats the high-pressure main steam with the exhaust heat, and a reheater that superheats the high-pressure main steam exhausted from the high-pressure turbine with the exhaust heat, in this order from the upstream with respect to the flow of the exhaust gas. The combined cycle power plant to be arranged and the operation method thereof are provided. Then, when the steam turbine is stopped, the high-pressure main steam generated in the high-pressure drum is introduced into the condenser through the high-pressure turbine bypass pipe, and the high-pressure main steam pressure adjusting means depressurizes the high-pressure main steam. By increasing the evaporation amount of the high-pressure drum to increase the heat absorption amount of the exhaust heat in the high-pressure superheater, the high-pressure drum evaporation amount does not exceed the allowable maximum evaporation amount of the high-pressure drum. The pressure of the high-pressure main steam in the turbine bypass pipe is adjusted, and the reheater does not exceed a heat-resistant allowable value due to the exhaust heat contained in the exhaust gas after being absorbed by the high-pressure superheater. As described above, the gas turbine can be operated independently by adjusting the operation load of the gas turbine.

本発明によると、ガスタービンの排熱で発生する蒸気が再熱器に戻らずに復水器に流れ込む構成であってもガスタービンを単独で運転可能なコンバインドサイクル型発電プラントおよび運転方法を提供できる。   According to the present invention, there is provided a combined cycle type power plant and an operation method capable of operating the gas turbine independently even when the steam generated by the exhaust heat of the gas turbine flows into the condenser without returning to the reheater. it can.

Ｃ／Ｃ発電プラントの概略構成図である。It is a schematic block diagram of a C / C power plant. 低圧タービンバイパス弁を制御する機能ブロックを示す図である。It is a figure which shows the functional block which controls a low pressure turbine bypass valve. 中圧タービンバイパス弁を制御する機能ブロックを示す図である。It is a figure which shows the functional block which controls an intermediate pressure turbine bypass valve. 中圧特性線図の一例を示す図である。It is a figure which shows an example of an intermediate pressure characteristic diagram. 高圧タービンバイパス弁を制御する機能ブロックを示す図である。It is a figure which shows the functional block which controls a high pressure turbine bypass valve. 高圧特性線図の一例を示す図である。It is a figure which shows an example of a high voltage | pressure characteristic diagram. ガスタービンを制御する機能ブロックを示す図である。It is a figure which shows the functional block which controls a gas turbine. タービン負荷特性線図の一例を示す図である。It is a figure which shows an example of a turbine load characteristic diagram. 運転負荷が切り替わる状態を示す図である。It is a figure which shows the state which a driving load switches.

以下、適宜図を参照して本発明の実施形態を詳細に説明する。
図１に示すように、本実施形態に係るコンバインドサイクル型発電プラント（Ｃ／Ｃ発電プラント１）は、ガスタービン１１と、蒸気タービン１０（高圧タービン１２、中圧タービン１３、低圧タービン１４）と、制御装置２と、を有して構成され、ガスタービン１１と蒸気タービン１０の出力軸のそれぞれに発電機Ｇが接続される多軸型の発電プラントである。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, a combined cycle power plant (C / C power plant 1) according to the present embodiment includes a gas turbine 11 and a steam turbine 10 (a high pressure turbine 12, an intermediate pressure turbine 13, and a low pressure turbine 14). The control device 2 is a multi-shaft power plant in which a generator G is connected to each of the output shafts of the gas turbine 11 and the steam turbine 10.

ガスタービン１１と蒸気タービン１０がともに運転される通常運転の場合、ガスタービン１１の排気側に設置される排熱回収ボイラ５４に備わる高圧ドラム２２で発生した蒸気は、高圧過熱器５４ｊ、高圧主蒸気管４５を流通して高圧タービン１２に流入する。高圧タービン１２で仕事をした蒸気（低温蒸気）は、低温再熱蒸気管４６を流通して排熱回収ボイラ５４に備わる再熱器５４ｉに流入し、ガスタービン１１から排気される排気ガスに含まれる熱量（以下、タービン排熱と称する）で加熱された後に高温再熱蒸気管４７、インターセプト弁８３を流通して中圧タービン１３に流入する。そして、中圧タービン１３で仕事をした蒸気はクロスオーバ管８１を流通して低圧タービン１４に流入する。   In the normal operation in which both the gas turbine 11 and the steam turbine 10 are operated, the steam generated in the high-pressure drum 22 provided in the exhaust heat recovery boiler 54 installed on the exhaust side of the gas turbine 11 is transferred to the high-pressure superheater 54j, the high-pressure main unit. It flows through the steam pipe 45 and flows into the high-pressure turbine 12. The steam (low-temperature steam) that has worked in the high-pressure turbine 12 flows through the low-temperature reheat steam pipe 46, flows into the reheater 54 i provided in the exhaust heat recovery boiler 54, and is included in the exhaust gas exhausted from the gas turbine 11. After being heated by the amount of heat generated (hereinafter referred to as turbine exhaust heat), it flows through the high-temperature reheat steam pipe 47 and the intercept valve 83 and flows into the intermediate pressure turbine 13. Then, the steam that has worked in the intermediate pressure turbine 13 flows through the crossover pipe 81 and flows into the low pressure turbine 14.

なお、高圧主蒸気管４５から、高圧主蒸気の圧力を調節する高圧タービンバイパス弁２３（高圧主蒸気圧力調節手段）および減温器８８が備わる高圧タービンバイパス管５１ａが分岐し、高圧主蒸気管４５は高圧タービンバイパス管５１ａを介して復水器１５と接続され、高圧ドラム２２で発生する高圧主蒸気を復水器１５に高圧タービン１２をバイパスして導入可能に、かつ、高圧主蒸気の圧力を調節可能に構成される。
また、高圧主蒸気管４５と高圧タービンバイパス管５１ａの分岐点と高圧タービン１２の間で高圧主蒸気管４５に高圧加減弁８２が備わる。
さらに、高圧主蒸気管４５に備わる高圧タービン入口圧力検出器２６によって、高圧主蒸気管４５を流通する蒸気の圧力（高圧主蒸気圧力）が検出され、高圧主蒸気管４５に備わる高圧流量検出器４０１によって、高圧主蒸気管４５を流通する蒸気の流量（高圧主蒸気流量）が検出される。 The high pressure main steam pipe 45 branches from the high pressure turbine bypass valve 23 (high pressure main steam pressure adjusting means) for adjusting the pressure of the high pressure main steam and the high pressure turbine bypass pipe 51a provided with the temperature reducer 88. 45 is connected to the condenser 15 via the high-pressure turbine bypass pipe 51a so that the high-pressure main steam generated in the high-pressure drum 22 can be introduced into the condenser 15 by bypassing the high-pressure turbine 12, and The pressure is adjustable.
The high pressure main steam pipe 45 is provided with a high pressure control valve 82 between the branch point of the high pressure main steam pipe 45 and the high pressure turbine bypass pipe 51 a and the high pressure turbine 12.
Further, the pressure of the steam (high pressure main steam pressure) flowing through the high pressure main steam pipe 45 is detected by the high pressure turbine inlet pressure detector 26 provided in the high pressure main steam pipe 45, and the high pressure flow rate detector provided in the high pressure main steam pipe 45. 401 detects the flow rate of steam flowing through the high-pressure main steam pipe 45 (high-pressure main steam flow rate).

低圧タービン１４から排出された蒸気は復水器１５で復水に凝縮され、低圧給水ポンプ１６で加圧されて給水管５０を流通し、グランド蒸気復水器１８を経由して排熱回収ボイラ５４の低圧節炭器５４ａに流入し、低圧節炭器５４ａを流通する間にタービン排熱で加熱されて低圧ドラム２０に流入する。また、給水管５０を流通する復水の一部は高中圧給水ポンプ１９で加圧されて排熱回収ボイラ５４の中圧節炭器５４ｃと高圧節炭器５４ｆに流れ込んでタービン排熱で加熱され、それぞれ中圧ドラム２１、高圧ドラム２２に流入する。
なお、高中圧給水ポンプ１９で加圧された復水の一部は、減温器８８に導入されて高圧タービンバイパス管５１ａを流通する高圧主蒸気の減温に利用され、気化して復水器１５に流入する。また、低圧給水ポンプ１６で加圧された復水の一部は、減温器８９に導入されて中圧タービンバイパス管５２ａを流通する中圧主蒸気の減温に利用され、気化して復水器１５に流入する。 Steam discharged from the low-pressure turbine 14 is condensed into condensate by the condenser 15, pressurized by the low-pressure feed water pump 16, circulated through the feed water pipe 50, and exhaust heat recovery boiler via the ground steam condenser 18. 54 flows into the low-pressure economizer 54 a and is heated by the turbine exhaust heat while flowing through the low-pressure economizer 54 a and flows into the low-pressure drum 20. Further, a part of the condensate flowing through the feed pipe 50 is pressurized by the high / medium pressure feed water pump 19 and flows into the medium pressure economizer 54c and the high pressure economizer 54f of the exhaust heat recovery boiler 54 and is heated by the turbine exhaust heat. And flow into the intermediate-pressure drum 21 and the high-pressure drum 22, respectively.
A part of the condensate pressurized by the high / medium-pressure feed water pump 19 is introduced into the temperature reducer 88 and used to reduce the temperature of the high-pressure main steam flowing through the high-pressure turbine bypass pipe 51a. Flows into the vessel 15. In addition, a part of the condensate pressurized by the low-pressure feed water pump 16 is introduced into the temperature reducer 89 and used to reduce the temperature of the medium-pressure main steam flowing through the medium-pressure turbine bypass pipe 52a. It flows into the water bottle 15.

低圧ドラム２０に流入した復水は低圧蒸発器５４ｂで加熱され高温の復水となって低圧ドラム２０に戻り、その一部が蒸気（飽和蒸気）となって低圧過熱器入口連絡管を経由して低圧過熱器５４ｄに流入する。そして、低圧過熱器５４ｄで加熱された蒸気は低圧主蒸気管４８によって中圧タービン１３の最終段に導かれクロスオーバ管８１を流通して低圧タービン１４に流入する。
なお、低圧主蒸気管４８から、低圧主蒸気の圧力を調節する低圧タービンバイパス弁２５（低圧主蒸気圧力調節手段）が備わる低圧タービンバイパス管５３が分岐し、低圧主蒸気管４８は低圧タービンバイパス管５３を介して復水器１５と接続される。そして、低圧ドラム２０で発生する低圧主蒸気を復水器１５に直接導入可能に、かつ、低圧主蒸気の圧力を調節可能に構成される。
また、低圧主蒸気管４８と低圧タービンバイパス管５３の分岐点と中圧タービン１３の間で低圧主蒸気管４８に低圧加減弁８４が備わる。
さらに、低圧主蒸気管４８に備わる低圧タービン入口圧力検出器２８によって、低圧主蒸気管４８を流通する蒸気の圧力（低圧主蒸気圧力）が検出され、低圧主蒸気管４８に備わる低圧流量検出器２０１によって、低圧主蒸気管４８を流通する蒸気の流量（低圧主蒸気流量）が検出される。 The condensate flowing into the low-pressure drum 20 is heated by the low-pressure evaporator 54b to become high-temperature condensate and returns to the low-pressure drum 20, and a part thereof becomes steam (saturated steam) via the low-pressure superheater inlet connecting pipe. And flows into the low pressure superheater 54d. Then, the steam heated by the low-pressure superheater 54 d is guided to the final stage of the intermediate-pressure turbine 13 by the low-pressure main steam pipe 48, flows through the crossover pipe 81, and flows into the low-pressure turbine 14.
A low-pressure turbine bypass pipe 53 provided with a low-pressure turbine bypass valve 25 (low-pressure main steam pressure adjusting means) for adjusting the pressure of the low-pressure main steam branches from the low-pressure main steam pipe 48, and the low-pressure main steam pipe 48 is a low-pressure turbine bypass. It is connected to the condenser 15 via a pipe 53. The low-pressure main steam generated in the low-pressure drum 20 can be directly introduced into the condenser 15 and the pressure of the low-pressure main steam can be adjusted.
Further, the low pressure main steam pipe 48 is provided with a low pressure adjusting valve 84 between the branch point of the low pressure main steam pipe 48 and the low pressure turbine bypass pipe 53 and the intermediate pressure turbine 13.
Further, the pressure of the steam (low pressure main steam pressure) flowing through the low pressure main steam pipe 48 is detected by the low pressure turbine inlet pressure detector 28 provided in the low pressure main steam pipe 48, and the low pressure flow rate detector provided in the low pressure main steam pipe 48. 201 detects the flow rate of the steam flowing through the low-pressure main steam pipe 48 (low-pressure main steam flow rate).

また、中圧ドラム２１に流入した復水は中圧蒸発器５４ｅで加熱され高温の復水となって中圧ドラム２１に戻り、その一部が飽和蒸気となって中圧過熱器入口連絡管を経由して中圧過熱器５４ｇに流入する。そして、中圧過熱器５４ｇで加熱された蒸気は中圧主蒸気管３９によって低温再熱蒸気管４６に流入する。
また、中圧主蒸気管３９から、中圧主蒸気の圧力を調節する中圧タービンバイパス弁２４（中圧主蒸気圧力調節手段）および減温器８９が備わる中圧タービンバイパス管５２ａが分岐し、中圧主蒸気管３９は中圧タービンバイパス管５２ａを介して復水器１５と接続される。そして、中圧ドラム２１で発生する中圧主蒸気を復水器１５に直接導入可能に、かつ、中圧主蒸気の圧力を調節可能に構成される。
また、中圧主蒸気管３９と中圧タービンバイパス管５２ａの分岐点と低温再熱蒸気管４６の間で中圧主蒸気管３９に中圧主蒸気遮断弁９１が備わる。
中圧主蒸気遮断弁９１は、蒸気タービン１０とガスタービン１１がともに運転される通常運転のときに開弁し、中圧ドラム２１で発生する中圧主蒸気を再熱器５４ｉを介して中圧タービン１３に供給する。また、蒸気タービン１０が停止してガスタービン１１が単独負荷運転するとき、中圧主蒸気遮断弁９１は閉弁する。 Further, the condensate flowing into the intermediate pressure drum 21 is heated by the intermediate pressure evaporator 54e to become high-temperature condensate and returns to the intermediate pressure drum 21, and a part thereof becomes saturated steam, and the intermediate pressure superheater inlet connecting pipe. To the intermediate pressure superheater 54g. Then, the steam heated by the intermediate pressure superheater 54 g flows into the low temperature reheat steam pipe 46 through the intermediate pressure main steam pipe 39.
An intermediate pressure turbine bypass pipe 52a provided with an intermediate pressure turbine bypass valve 24 (intermediate pressure main steam pressure adjusting means) for adjusting the pressure of the intermediate pressure main steam and a temperature reducer 89 branches from the intermediate pressure main steam pipe 39. The intermediate pressure main steam pipe 39 is connected to the condenser 15 via the intermediate pressure turbine bypass pipe 52a. The intermediate pressure main steam generated by the intermediate pressure drum 21 can be directly introduced into the condenser 15 and the pressure of the intermediate pressure main steam can be adjusted.
Further, an intermediate pressure main steam cutoff valve 91 is provided in the intermediate pressure main steam pipe 39 between the branch point of the intermediate pressure main steam pipe 39 and the intermediate pressure turbine bypass pipe 52 a and the low temperature reheat steam pipe 46.
The intermediate pressure main steam cutoff valve 91 is opened during normal operation in which both the steam turbine 10 and the gas turbine 11 are operated, and the intermediate pressure main steam generated in the intermediate pressure drum 21 is intermediated via the reheater 54i. Supply to pressure turbine 13. Further, when the steam turbine 10 is stopped and the gas turbine 11 is operated with a single load, the intermediate pressure main steam cutoff valve 91 is closed.

さらに、中圧主蒸気管３９に備わる中圧タービン入口圧力検出器２７によって、中圧主蒸気管３９を流通する蒸気の圧力（中圧主蒸気圧力）が検出され、中圧主蒸気管３９に備わる中圧流量検出器３０１によって、中圧主蒸気管３９を流通する蒸気の流量（中圧主蒸気流量）が検出される。   Further, the pressure of the steam flowing through the intermediate pressure main steam pipe 39 (intermediate pressure main steam pressure) is detected by the intermediate pressure turbine inlet pressure detector 27 provided in the intermediate pressure main steam pipe 39. An intermediate pressure flow rate detector 301 provided therein detects the flow rate of the steam flowing through the intermediate pressure main steam pipe 39 (intermediate pressure main steam flow rate).

また、高圧ドラム２２に流入した復水は高圧蒸発器５４ｈで加熱され高温の復水となって高圧ドラム２２に戻り、その一部が飽和蒸気となって高圧過熱器入口連絡管を経由して高圧過熱器５４ｊに流入し、前記したように高圧主蒸気管４５を流通して高圧タービン１２に流入する。   Further, the condensate flowing into the high-pressure drum 22 is heated by the high-pressure evaporator 54h to become high-temperature condensate and returns to the high-pressure drum 22, and a part thereof becomes saturated steam and passes through the high-pressure superheater inlet connecting pipe. It flows into the high pressure superheater 54j, flows through the high pressure main steam pipe 45 as described above, and flows into the high pressure turbine 12.

なお、排熱回収ボイラ５４には脱硝装置９２が備わり、ガスタービン１１から排出されるガスに含まれる窒素酸化物が窒素と水蒸気に分解されるように構成される。
また、符号９０は高圧タービン１２の初段後圧力を検出する高圧タービン初段後圧力検出器である。 The exhaust heat recovery boiler 54 is provided with a denitration device 92 so that nitrogen oxides contained in the gas discharged from the gas turbine 11 are decomposed into nitrogen and water vapor.
Reference numeral 90 denotes a high-pressure turbine first-stage post-pressure detector that detects the first-stage post-stage pressure of the high-pressure turbine 12.

以上のように構成されるＣ／Ｃ発電プラント１は、蒸気タービン１０（高圧タービン１２、中圧タービン１３、低圧タービン１４）を停止してガスタービン１１を単独負荷運転する場合、高圧加減弁８２、インターセプト弁８３、および、低圧加減弁８４を閉弁して蒸気タービン１０（高圧タービン１２、中圧タービン１３、低圧タービン１４）への蒸気の供給を遮断するように制御される。   When the C / C power plant 1 configured as described above stops the steam turbine 10 (the high-pressure turbine 12, the intermediate-pressure turbine 13, and the low-pressure turbine 14) and operates the gas turbine 11 with a single load, the high-pressure control valve 82 is provided. The intercept valve 83 and the low pressure adjusting valve 84 are closed to control the supply of steam to the steam turbine 10 (the high pressure turbine 12, the intermediate pressure turbine 13, and the low pressure turbine 14).

しかしながら、ガスタービン１１を単独負荷運転する場合に再熱器５４ｉに蒸気が流入しないとガスタービン１１から排気される排気ガスに含まれるタービン排熱によって再熱器５４ｉの温度が上昇し、設計温度を超えると再熱器５４ｉが破損するなどの問題が発生する。
そこで、本実施形態の制御装置２は、ガスタービン１１の単独負荷運転の時に再熱器５４ｉにおけるタービン排熱の熱量を下げるようにＣ／Ｃ発電プラント１を制御する。 However, when the gas turbine 11 is operated with a single load, if the steam does not flow into the reheater 54i, the temperature of the reheater 54i rises due to the turbine exhaust heat contained in the exhaust gas exhausted from the gas turbine 11, and the design temperature Exceeding this causes problems such as breakage of the reheater 54i.
Therefore, the control device 2 of the present embodiment controls the C / C power plant 1 so as to reduce the amount of turbine exhaust heat in the reheater 54 i when the gas turbine 11 is operated with a single load.

具体的に制御装置２は、ガスタービン１１の排気ガスの流れにおいて再熱器５４ｉの上流に配置される高圧過熱器５４ｊでの交換熱量（タービン排熱の吸収熱量）を増やして再熱器５４ｉにおけるタービン排熱の熱量を下げる。
そのため制御装置２は、高圧タービンバイパス弁２３を開いて高圧主蒸気管４５、および、高圧タービンバイパス管５１ａの蒸気を真空状態の復水器１５に導入して高圧主蒸気を減圧する。このことによって高圧ドラム２２における飽和蒸気温度が低下して高圧ドラム２２での蒸発量が増え、高圧過熱器５４ｊを流れる蒸気流量が増えることによって高圧過熱器５４ｊでの交換熱量が増える。この結果、再熱器５４ｉの過熱が抑制される。 Specifically, the control device 2 increases the exchange heat amount (absorption heat amount of the turbine exhaust heat) in the high-pressure superheater 54j disposed upstream of the reheater 54i in the exhaust gas flow of the gas turbine 11, thereby increasing the reheater 54i. Reduce the amount of turbine exhaust heat.
Therefore, the control device 2 opens the high-pressure turbine bypass valve 23, introduces the steam from the high-pressure main steam pipe 45 and the high-pressure turbine bypass pipe 51a into the vacuum condenser 15, and decompresses the high-pressure main steam. As a result, the saturated steam temperature in the high-pressure drum 22 is lowered, the amount of evaporation in the high-pressure drum 22 is increased, and the amount of steam flowing through the high-pressure superheater 54j is increased, whereby the amount of exchange heat in the high-pressure superheater 54j is increased. As a result, overheating of the reheater 54i is suppressed.

しかしながら、高圧ドラム２２には許容最大蒸発量が設計値として設定されているため、この許容最大蒸発量を超えないように蒸発量が設定されることが好ましい。高圧ドラム２２の蒸発量は内部の蒸気圧によって決まり、高圧ドラム２２の内部の蒸気圧は高圧タービンバイパス弁２３の開度によって決定される。
つまり、高圧ドラム２２の蒸発量が許容最大蒸発量を超えないように高圧タービンバイパス弁２３の開度が設定されることが要求される。 However, since the allowable maximum evaporation amount is set as a design value for the high-pressure drum 22, it is preferable to set the evaporation amount so as not to exceed the allowable maximum evaporation amount. The evaporation amount of the high pressure drum 22 is determined by the internal steam pressure, and the internal steam pressure of the high pressure drum 22 is determined by the opening degree of the high pressure turbine bypass valve 23.
That is, the opening degree of the high-pressure turbine bypass valve 23 is required to be set so that the evaporation amount of the high-pressure drum 22 does not exceed the allowable maximum evaporation amount.

本実施形態において制御装置２は、以下のようにガスタービン１１の運転負荷、高圧タービンバイパス弁２３の開度、中圧タービンバイパス弁２４の開度、および、低圧タービンバイパス弁２５の開度を設定してガスタービン１１を単独負荷運転する。   In the present embodiment, the control device 2 determines the operating load of the gas turbine 11, the opening of the high pressure turbine bypass valve 23, the opening of the intermediate pressure turbine bypass valve 24, and the opening of the low pressure turbine bypass valve 25 as follows. The gas turbine 11 is operated with a single load by setting.

《ガスタービン１１の運転負荷の設定》
制御装置２は、Ｃ／Ｃ発電プラント１の蒸気タービン１０を停止してガスタービン１１の単独負荷運転に切り替える場合にガスタービン１１の運転負荷を決定するが、このとき制御装置２は、高圧ドラム２２の蒸発量が変化しない状態（つまり、高圧過熱器５４ｊでの交換熱量が変化しない状態）で排気ガスの温度が再熱器５４ｉの耐熱温度以下となるガスタービン１１の運転負荷の最大値をガスタービン１１の運転負荷に決定する。 << Setting of Operation Load of Gas Turbine 11 >>
The control device 2 determines the operation load of the gas turbine 11 when the steam turbine 10 of the C / C power plant 1 is stopped and switched to the single load operation of the gas turbine 11. The maximum value of the operating load of the gas turbine 11 at which the exhaust gas temperature is equal to or lower than the heat resistance temperature of the reheater 54i in a state where the evaporation amount of 22 does not change (that is, the exchange heat amount in the high pressure superheater 54j does not change) The operating load of the gas turbine 11 is determined.

この運転負荷は再熱器５４ｉの耐熱温度、高圧ドラム２２の蒸発量に応じて決定される値である。例えば、高圧ドラム２２の蒸発量と、高圧過熱器５４ｊを通過した排気ガスの温度と、ガスタービン１１の運転負荷と、の関係を示すマップ形式のデータが予め設定されている構成とすれば、制御装置２は高圧ドラム２２の蒸発量に基づいて当該マップ形式のデータを参照することによって、排気ガスの温度が再熱器５４ｉの耐熱温度以下となるガスタービン１１の運転負荷を決定できる。なお、排気ガスの温度と運転負荷がマップ形式のデータで設定されることは一例であり、制御装置２が参照できる形態であればマップ形式に限定されるものではない。   This operating load is a value determined according to the heat resistance temperature of the reheater 54 i and the evaporation amount of the high-pressure drum 22. For example, if the map format data indicating the relationship between the evaporation amount of the high-pressure drum 22, the temperature of the exhaust gas that has passed through the high-pressure superheater 54j, and the operating load of the gas turbine 11 is set in advance, The control device 2 can determine the operation load of the gas turbine 11 at which the exhaust gas temperature is equal to or lower than the heat resistance temperature of the reheater 54 i by referring to the map format data based on the evaporation amount of the high-pressure drum 22. It should be noted that the exhaust gas temperature and the operating load are set as map format data, and are not limited to the map format as long as the control device 2 can refer to them.

《低圧タービンバイパス弁２５の開度設定》
制御装置２は、蒸気タービン１０を停止すると、低圧タービンバイパス弁２５の開度を調節して低圧主蒸気圧力を制御する。低圧タービンバイパス弁２５が開弁すると低圧ドラム２０は低圧過熱器５４ｄを介して復水器１５と連通して内部が減圧する。低圧ドラム２０では減圧にともなって飽和温度が低下して蒸発量が増える。
制御装置２は、低圧ドラム２０の蒸発量が予め設定される許容値（許容最大蒸発量）を超えない範囲で最大の蒸発量となるような低圧主蒸気圧力の初期値（低圧圧力初期値）を設定し、低圧タービンバイパス弁２５の開度は、低圧タービンバイパス管５３の低圧主蒸気圧力が低圧圧力初期値となるように制御される。この低圧圧力初期値は予め決定されている値であってもよい。 << Opening setting of low-pressure turbine bypass valve 25 >>
When the steam turbine 10 is stopped, the control device 2 controls the low-pressure main steam pressure by adjusting the opening degree of the low-pressure turbine bypass valve 25. When the low-pressure turbine bypass valve 25 is opened, the low-pressure drum 20 communicates with the condenser 15 through the low-pressure superheater 54d to reduce the pressure inside. In the low-pressure drum 20, the saturation temperature is lowered and the evaporation amount is increased as the pressure is reduced.
The control device 2 sets the initial value (low pressure initial value) of the low pressure main steam pressure so that the evaporation amount of the low pressure drum 20 becomes the maximum evaporation amount within a range not exceeding the preset allowable value (allowable maximum evaporation amount). And the opening degree of the low-pressure turbine bypass valve 25 is controlled so that the low-pressure main steam pressure of the low-pressure turbine bypass pipe 53 becomes the low-pressure pressure initial value. The low pressure initial value may be a predetermined value.

《中圧タービンバイパス弁２４の開度設定》
制御装置２は、蒸気タービン１０を停止すると、中圧タービンバイパス弁２４の開度を調節して中圧ドラム２１の蒸発量を設定する。低圧ドラム２０と同様に中圧タービンバイパス弁２４が開弁すると中圧ドラム２１は中圧過熱器５４ｇを介して復水器１５と連通し、内部が減圧する。中圧ドラム２１では減圧にともなって飽和温度が低下して蒸発量が増える。
制御装置２は、中圧ドラム２１の蒸発量が予め設定される許容値（許容最大蒸発量）を超えない範囲で最大の蒸発量となるような中圧主蒸気圧力の初期値（中圧圧力初期値）を設定し、中圧タービンバイパス弁２４の開度は、中圧タービンバイパス管５２ａの中圧主蒸気圧力が中圧圧力初期値となるように制御される。この中圧圧力初期値は予め決定されている値であってもよい。 << Opening setting of intermediate pressure turbine bypass valve 24 >>
When the steam turbine 10 is stopped, the control device 2 adjusts the opening degree of the intermediate pressure turbine bypass valve 24 and sets the evaporation amount of the intermediate pressure drum 21. Similarly to the low-pressure drum 20, when the intermediate-pressure turbine bypass valve 24 is opened, the intermediate-pressure drum 21 communicates with the condenser 15 through the intermediate-pressure superheater 54g, and the inside is depressurized. In the intermediate pressure drum 21, the saturation temperature is lowered and the evaporation amount is increased as the pressure is reduced.
The control device 2 determines the initial value (intermediate pressure pressure) of the intermediate pressure main steam pressure so that the evaporation amount of the intermediate pressure drum 21 becomes the maximum evaporation amount within a range that does not exceed a preset allowable value (allowable maximum evaporation amount). An initial value) is set, and the opening degree of the intermediate pressure turbine bypass valve 24 is controlled such that the intermediate pressure main steam pressure of the intermediate pressure turbine bypass pipe 52a becomes the intermediate pressure initial value. The intermediate pressure initial value may be a predetermined value.

《高圧タービンバイパス弁２３の開度設定》
また、制御装置２は、蒸気タービン１０を停止すると、高圧タービンバイパス弁２３の開度を調節して高圧ドラム２２の蒸発量を設定する。低圧ドラム２０と同様に高圧タービンバイパス弁２３が開弁すると高圧ドラム２２は高圧過熱器５４ｊを介して復水器１５と連通し、内部が減圧する。高圧ドラム２２では減圧にともなって飽和温度が低下して蒸発量が増える。
制御装置２は、高圧ドラム２２の蒸発量が予め設定される許容値（許容最大蒸発量）を超えない範囲で最大の蒸発量となるような高圧主蒸気圧力の初期値（高圧圧力初期値）を設定し、高圧タービンバイパス弁２３の開度は、高圧タービンバイパス管５１ａの高圧主蒸気圧力が高圧圧力初期値となるように制御される。この高圧圧力初期値は予め決定されている値であってもよい。 << Opening setting of high-pressure turbine bypass valve 23 >>
Further, when the steam turbine 10 is stopped, the control device 2 adjusts the opening degree of the high-pressure turbine bypass valve 23 and sets the evaporation amount of the high-pressure drum 22. As with the low pressure drum 20, when the high pressure turbine bypass valve 23 is opened, the high pressure drum 22 communicates with the condenser 15 via the high pressure superheater 54j, and the inside is depressurized. In the high-pressure drum 22, the saturation temperature decreases and the amount of evaporation increases as the pressure decreases.
The control device 2 sets the initial value (high pressure initial value) of the high-pressure main steam pressure so that the evaporation amount of the high-pressure drum 22 becomes the maximum evaporation amount within a range not exceeding a preset allowable value (allowable maximum evaporation amount). And the opening degree of the high-pressure turbine bypass valve 23 is controlled so that the high-pressure main steam pressure of the high-pressure turbine bypass pipe 51a becomes the high-pressure pressure initial value. The high pressure initial value may be a predetermined value.

制御装置２は蒸気タービン１０を停止したとき、前記のように、ガスタービン１１の運転負荷、高圧圧力初期値、中圧圧力初期値、および、低圧圧力初期値を設定する。そして、制御装置２はガスタービン１１を単独負荷運転する間、ガスタービン１１の運転負荷、高圧タービンバイパス弁２３の開度、中圧タービンバイパス弁２４の開度、および、低圧タービンバイパス弁２５の開度を以下のように連続して制御（調節）する。   When the steam turbine 10 is stopped, the control device 2 sets the operation load, the high pressure initial value, the medium pressure initial value, and the low pressure initial value of the gas turbine 11 as described above. While the control device 2 operates the gas turbine 11 alone, the operation load of the gas turbine 11, the opening of the high-pressure turbine bypass valve 23, the opening of the intermediate-pressure turbine bypass valve 24, and the low-pressure turbine bypass valve 25 The opening degree is continuously controlled (adjusted) as follows.

《低圧タービンバイパス弁２５の開度調節》
制御装置２は、図２に示す機能ブロックを含んで構成され、低圧タービンバイパス弁２５を制御する。図２に示すように制御装置２は、低圧タービン入口圧力検出器２８の検出値を低圧主蒸気管４８における低圧主蒸気の圧力（低圧主蒸気圧力）の実測値とし、低圧主蒸気管４８に許容される最大値（低圧主蒸気許容最大圧力値）から、低圧主蒸気圧力の実測値を減算器１００ｂで減算した偏差（低圧主蒸気圧偏差ΔＰＬ）を演算する。そして制御装置２は、例えば、ＰＩ動作器１００ｃでのＰＩ動作（比例・積分動作）によって低圧主蒸気圧偏差ΔＰＬをゼロとするように低圧タービンバイパス弁２５の開度を調節する。 << Opening degree adjustment of low-pressure turbine bypass valve 25 >>
The control device 2 includes the functional blocks shown in FIG. 2 and controls the low pressure turbine bypass valve 25. As shown in FIG. 2, the control device 2 uses the detected value of the low-pressure turbine inlet pressure detector 28 as an actual measurement value of the pressure of the low-pressure main steam (low-pressure main steam pressure) in the low-pressure main steam pipe 48. A deviation (low pressure main steam pressure deviation ΔPL) obtained by subtracting the measured value of the low pressure main steam pressure by the subtractor 100b from the allowable maximum value (low pressure main steam allowable maximum pressure value) is calculated. Then, the control device 2 adjusts the opening degree of the low-pressure turbine bypass valve 25 so that the low-pressure main steam pressure deviation ΔPL becomes zero by, for example, the PI operation (proportional / integral operation) in the PI operating unit 100c.

低圧主蒸気圧偏差ΔＰＬが正のとき、低圧主蒸気圧力の実測値を高くするため制御装置２は低圧タービンバイパス弁２５を閉じる方向に調節し、低圧主蒸気圧偏差ΔＰＬが負のとき、低圧主蒸気圧力の実測値を低くするため制御装置２は低圧タービンバイパス弁２５を開く方向に調節する。
なお、蒸気タービン１０が停止していないとき（つまり、蒸気タービン１０とガスタービン１１がともに運転される通常運転のとき）、制御装置２は、低圧主蒸気許容最大圧力値に替えて、予め設定される低圧設定値を選択器１００ａで選択する。この低圧設定値は、通常運転のときに低圧タービン１４に設定される固定値であってＣ／Ｃ発電プラント１（図１参照）の特性値として決定される。 When the low-pressure main steam pressure deviation ΔPL is positive, the control device 2 adjusts the low-pressure turbine bypass valve 25 to close in order to increase the measured value of the low-pressure main steam pressure, and when the low-pressure main steam pressure deviation ΔPL is negative, In order to lower the actual measurement value of the main steam pressure, the control device 2 adjusts the low-pressure turbine bypass valve 25 to open.
Note that when the steam turbine 10 is not stopped (that is, during normal operation in which both the steam turbine 10 and the gas turbine 11 are operated), the control device 2 sets in advance instead of the low-pressure main steam allowable maximum pressure value. The low pressure set value to be set is selected by the selector 100a. This low pressure set value is a fixed value set in the low pressure turbine 14 during normal operation and is determined as a characteristic value of the C / C power plant 1 (see FIG. 1).

制御装置２は減算器１００ｂで、選択した低圧設定値から低圧主蒸気圧力の実測値を減算して低圧主蒸気圧偏差ΔＰＬを演算し、低圧主蒸気圧偏差ΔＰＬをゼロとするように低圧タービンバイパス弁２５を制御する。
以上のような手順で制御装置２は、低圧タービンバイパス弁２５を制御して開度を調節し、低圧タービンバイパス管５３における低圧主蒸気の圧力を調節する。 The control device 2 is a subtractor 100b that calculates the low-pressure main steam pressure deviation ΔPL by subtracting the actual measurement value of the low-pressure main steam pressure from the selected low-pressure set value, so that the low-pressure main steam pressure deviation ΔPL is zero. The bypass valve 25 is controlled.
The control device 2 controls the low-pressure turbine bypass valve 25 to adjust the opening degree and adjust the pressure of the low-pressure main steam in the low-pressure turbine bypass pipe 53 in the above procedure.

《中圧タービンバイパス弁２４の開度調節》
制御装置２は、図３に示す機能ブロックを含んで構成され、低圧主蒸気管４８（図１参照）における低圧主蒸気の蒸気流量が低圧許容最大流量未満となるように中圧タービンバイパス弁２４を制御する。図３に示すように制御装置２は、低圧主蒸気管４８に備わる低圧流量検出器２０１の検出値を低圧主蒸気管４８における低圧主蒸気流量の実測値とし、低圧主蒸気管４８に許容される低圧許容最大流量から実測値を減算器２００ａで減算（低圧許容最大流量−実測値）して低圧流量偏差ΔＦＬを算出する。
また、制御装置２は、ガスタービン１１の運転負荷と、現在設定されている中圧主蒸気圧力目標値に対応する低圧主蒸気管４８の流量（低圧主蒸気流量）を流量予測器２００ｂで予測する。本実施形態において制御装置２は、図４に示す特性線図（中圧特性線図）に基づいて低圧主蒸気流量を予測する。
さらに制御装置２は、算出した低圧流量偏差ΔＦＬがゼロとなるように、予測した低圧主蒸気流量を変化させるために必要な中圧主蒸気圧力目標値を演算する。 << Adjustment of Opening of Intermediate Pressure Turbine Bypass Valve 24 >>
The control device 2 is configured to include the functional blocks shown in FIG. 3, and the intermediate pressure turbine bypass valve 24 so that the steam flow rate of the low pressure main steam in the low pressure main steam pipe 48 (see FIG. 1) is less than the low pressure allowable maximum flow rate. To control. As shown in FIG. 3, the control device 2 uses the detected value of the low-pressure flow detector 201 provided in the low-pressure main steam pipe 48 as an actual measurement value of the low-pressure main steam flow in the low-pressure main steam pipe 48 and is allowed in the low-pressure main steam pipe 48. The subtractor 200a subtracts the actually measured value from the low pressure allowable maximum flow rate (low pressure allowable maximum flow rate−actual value) to calculate the low pressure flow rate deviation ΔFL.
Further, the control device 2 predicts the flow rate (low pressure main steam flow rate) of the low pressure main steam pipe 48 corresponding to the operation load of the gas turbine 11 and the currently set intermediate pressure main steam pressure target value by the flow rate predictor 200b. To do. In the present embodiment, the control device 2 predicts the low-pressure main steam flow rate based on the characteristic diagram (intermediate pressure characteristic diagram) shown in FIG.
Further, the control device 2 calculates the intermediate pressure main steam pressure target value necessary for changing the predicted low pressure main steam flow so that the calculated low pressure flow deviation ΔFL becomes zero.

例えば、図４に示すように、ガスタービン１１の運転負荷が「Ｗ１」で、現在設定されている中圧主蒸気圧力目標値が「ＰＭ１」のとき、制御装置２は中圧特性線図に基づいて、低圧主蒸気流量を「ＦＬ１」と予測する。
さらに、制御装置２は、低圧流量偏差ΔＦＬが正の場合（つまり、低圧主蒸気流量の実測値が低圧許容最大流量より小さい場合）、低圧主蒸気流量の予測値である「ＦＬ１」よりもΔＦＬだけ高い「ＦＬ３」を低圧主蒸気流量とし、「ＦＬ３」に対応する中圧主蒸気圧力「ＰＭ３」を中圧主蒸気圧力目標値とする。一方、低圧流量偏差ΔＦＬが負の場合（つまり、低圧主蒸気流量の実測値が低圧許容最大流量より大きい場合）、制御装置２は、低圧主蒸気流量の予測値である「ＦＬ１」よりもΔＦＬだけ低い「ＦＬ２」を低圧主蒸気流量とし、「ＦＬ２」に対応する中圧主蒸気圧力「ＰＭ２」を中圧主蒸気圧力目標値とする。 For example, as shown in FIG. 4, when the operation load of the gas turbine 11 is “W1” and the currently set intermediate pressure main steam pressure target value is “PM1”, the control device 2 displays an intermediate pressure characteristic diagram. Based on this, the low-pressure main steam flow rate is predicted as “FL1”.
Further, when the low-pressure flow deviation ΔFL is positive (that is, when the measured value of the low-pressure main steam flow is smaller than the low-pressure allowable maximum flow), the control device 2 is more than ΔFL than “FL1” that is the predicted value of the low-pressure main steam flow. “FL3”, which is higher than that, is set as the low-pressure main steam flow rate, and the intermediate-pressure main steam pressure “PM3” corresponding to “FL3” is set as the intermediate-pressure main steam pressure target value. On the other hand, when the low-pressure flow deviation ΔFL is negative (that is, when the measured value of the low-pressure main steam flow is larger than the low-pressure allowable maximum flow), the control device 2 is more than ΔFL than “FL1” that is the predicted value of the low-pressure main steam flow. “FL2”, which is lower than this, is set as the low-pressure main steam flow rate, and the intermediate-pressure main steam pressure “PM2” corresponding to “FL2” is set as the intermediate-pressure main steam pressure target value.

また制御装置２は、図３に示すローモニタ２０７で、中圧主蒸気管３９に許容される中圧許容最大流量から中圧流量検出器３０１が検出する中圧主蒸気流量の実測値を減算した値を監視する。ローモニタ２０７は、中圧許容最大流量から中圧主蒸気流量の実測値を減算した値が正のとき、すなわち、中圧主蒸気流量が中圧許容最大流量の実測値よりも小さいときは、流量予測器２００ｂで予測する中圧主蒸気圧力目標値を出力するように選択器２００ｃの出力を切り替える。一方、中圧許容最大流量の実測値から中圧主蒸気流量を減算した値が負のとき、すなわち、中圧主蒸気流量が中圧許容最大流量の実測値よりも大きいとき、ローモニタ２０７は出力を保持するように選択器２００ｃの出力を切り替える。   Further, the control device 2 subtracts the actual measurement value of the intermediate pressure main steam flow detected by the intermediate pressure flow detector 301 from the maximum allowable intermediate pressure flow allowed in the intermediate pressure main steam pipe 39 with the low monitor 207 shown in FIG. Monitor the value. When the value obtained by subtracting the measured value of the medium pressure main steam flow rate from the medium pressure allowable maximum flow rate is positive, that is, when the medium pressure main steam flow rate is smaller than the measured value of the medium pressure allowable maximum flow rate, the low monitor 207 The output of the selector 200c is switched so as to output the intermediate pressure main steam pressure target value predicted by the predictor 200b. On the other hand, when the value obtained by subtracting the intermediate pressure main steam flow rate from the actual measurement value of the maximum allowable intermediate pressure flow rate is negative, that is, when the intermediate pressure main steam flow rate is larger than the actual measurement value of the maximum allowable intermediate pressure flow rate, the low monitor 207 outputs To switch the output of the selector 200c.

制御装置２は、選択器２００ｃから選択器２００ｄを経由して出力される中圧主蒸気圧力目標値から中圧タービン入口圧力検出器２７が検出する中圧主蒸気圧力の実測値を減算器２００ｅで減算（中圧主蒸気圧力目標値−実測値）して中圧主蒸気圧偏差ΔＰＭを算出する。そして制御装置２は、例えば、ＰＩ動作器２００ｆでのＰＩ動作によって中圧主蒸気圧偏差ΔＰＭをゼロとするように中圧タービンバイパス弁２４の開度を調節する。
中圧主蒸気圧偏差ΔＰＭが正のとき、中圧主蒸気圧力を高くするため制御装置２は中圧タービンバイパス弁２４を閉じる方向に調節し、中圧主蒸気圧偏差ΔＰＭが負のとき、中圧主蒸気圧力を低くするため制御装置２は中圧タービンバイパス弁２４を開く方向に調節する。 The control device 2 subtracts the actual measured value of the intermediate pressure main steam pressure detected by the intermediate pressure turbine inlet pressure detector 27 from the intermediate pressure main steam pressure target value output from the selector 200c via the selector 200d. Is subtracted (medium pressure main steam pressure target value-actual value) to calculate medium pressure main steam pressure deviation ΔPM. And the control apparatus 2 adjusts the opening degree of the intermediate pressure turbine bypass valve 24 so that the intermediate pressure main steam pressure deviation ΔPM becomes zero, for example, by the PI operation in the PI operation unit 200f.
When the intermediate pressure main steam pressure deviation ΔPM is positive, the control device 2 adjusts the intermediate pressure turbine bypass valve 24 to close in order to increase the intermediate pressure main steam pressure, and when the intermediate pressure main steam pressure deviation ΔPM is negative, In order to lower the medium-pressure main steam pressure, the control device 2 adjusts the medium-pressure turbine bypass valve 24 in the opening direction.

なお、蒸気タービン１０が停止していない場合に制御装置２は、演算した中圧主蒸気圧力目標値に替えて、高圧タービン初段後圧力検出器９０が検出する高圧タービン１２の初段後圧力に応じて関数発生器２００ｇで決定される目標圧力を選択器２００ｄで選択して中圧主蒸気圧力目標値とする。蒸気タービン１０が停止していない場合（つまり、ガスタービン１１と蒸気タービン１０がともに運転される通常運転の場合）、関数発生器２００ｇで決定される目標圧力は中圧タービンバイパス弁２４が閉弁するように決定される。
なお、中圧特性線図は、マップ形式であってもテーブル形式であっても関数形式であってもよく、制御装置２が参照できる形式であれば、そのデータ形式は限定されない。 When the steam turbine 10 is not stopped, the control device 2 replaces the calculated intermediate pressure main steam pressure target value with the pressure after the first stage of the high pressure turbine 12 detected by the pressure detector 90 after the first stage of the high pressure turbine. Then, the target pressure determined by the function generator 200g is selected by the selector 200d to obtain the intermediate pressure main steam pressure target value. When the steam turbine 10 is not stopped (that is, in the normal operation in which both the gas turbine 11 and the steam turbine 10 are operated), the intermediate pressure turbine bypass valve 24 is closed as the target pressure determined by the function generator 200g. To be decided.
The intermediate pressure characteristic diagram may be a map format, a table format, or a function format, and the data format is not limited as long as the control device 2 can refer to it.

以上のような手順で制御装置２は、中圧タービンバイパス弁２４を制御して開度を調節し、中圧タービンバイパス管５２ａにおける中圧主蒸気の圧力を調節する。
図１に示す中圧タービンバイパス弁２４の開度が変化すると中圧ドラム２１の蒸発量が変化し、中圧過熱器５４ｇでの交換熱量（タービン排熱からの吸熱量）が変化する。それによって、中圧過熱器５４ｇの下流に備わる低圧蒸発器５４ｂを通過する排気ガスに含まれるタービン排熱の熱量が変化して低圧ドラム２０における復水の温度が変化し、これによって低圧ドラム２０の蒸発量が変化する。したがって、中圧タービンバイパス弁２４の開度を調節することによって低圧主蒸気管４８における低圧主蒸気流量を調節できる。 The control device 2 controls the intermediate pressure turbine bypass valve 24 to adjust the opening degree by the procedure as described above, and adjusts the pressure of the intermediate pressure main steam in the intermediate pressure turbine bypass pipe 52a.
When the opening degree of the intermediate pressure turbine bypass valve 24 shown in FIG. 1 changes, the evaporation amount of the intermediate pressure drum 21 changes, and the exchange heat amount (heat absorption amount from the turbine exhaust heat) in the intermediate pressure superheater 54g changes. As a result, the amount of turbine exhaust heat contained in the exhaust gas passing through the low-pressure evaporator 54b provided downstream of the intermediate-pressure superheater 54g changes, and the condensate temperature in the low-pressure drum 20 changes, whereby the low-pressure drum 20 The amount of evaporation changes. Therefore, the low pressure main steam flow rate in the low pressure main steam pipe 48 can be adjusted by adjusting the opening degree of the intermediate pressure turbine bypass valve 24.

《高圧タービンバイパス弁２３の開度調節》
制御装置２は、図５に示す機能ブロックを含んで構成され、中圧主蒸気管３９（図１参照）における中圧主蒸気の蒸気流量が中圧許容最大流量未満となるように高圧タービンバイパス弁２３を制御する。図５に示すように制御装置２は、中圧主蒸気管３９に備わる中圧流量検出器３０１の検出値を中圧主蒸気管３９における中圧主蒸気流量の実測値とし、中圧主蒸気管３９に許容される中圧許容最大流量から実測値を減算器３００ａで減算（中圧許容最大流量−実測値）して中圧流量偏差ΔＦＭを算出する。さらに制御装置２は、選択器２００ｄ（図３参照）で選択される中圧主蒸気圧力目標値で、予め設定される中圧設定値を除算器３００ｂで除算して補正係数ｋを算出する。そして制御装置２は、算出した補正係数ｋを中圧流量偏差ΔＦＭに乗算器３００ｃで乗算して中圧流量偏差ΔＦＭを補正する。予め設定される中圧設定値は、後記する高圧特性線図を設定する条件となる固定値であり、Ｃ／Ｃ発電プラント１の構成によって決定される特性値である。 << Adjustment of opening degree of high-pressure turbine bypass valve 23 >>
The control device 2 is configured to include the functional blocks shown in FIG. 5, and the high pressure turbine bypass so that the steam flow rate of the intermediate pressure main steam in the intermediate pressure main steam pipe 39 (see FIG. 1) is less than the maximum allowable intermediate pressure flow rate. The valve 23 is controlled. As shown in FIG. 5, the control device 2 uses the detected value of the intermediate pressure flow detector 301 provided in the intermediate pressure main steam pipe 39 as the actual measurement value of the intermediate pressure main steam flow in the intermediate pressure main steam pipe 39, and the intermediate pressure main steam. An intermediate pressure flow rate deviation ΔFM is calculated by subtracting an actual measured value from the maximum allowable medium pressure flow allowed in the pipe 39 by the subtractor 300a (intermediate allowable pressure maximum flow−actual measured value). Further, the control device 2 calculates the correction coefficient k by dividing the preset intermediate pressure by the divider 300b by the intermediate pressure main steam pressure target value selected by the selector 200d (see FIG. 3). Then, the control device 2 corrects the intermediate pressure flow deviation ΔFM by multiplying the calculated correction coefficient k by the multiplier 300c by the intermediate pressure flow deviation ΔFM. The intermediate pressure setting value set in advance is a fixed value that is a condition for setting a high-pressure characteristic diagram to be described later, and is a characteristic value determined by the configuration of the C / C power plant 1.

また、制御装置２は圧力演算器３００ｄで、ガスタービン１１の運転負荷と現在設定されている高圧主蒸気圧力目標値に対応する中圧主蒸気管３９の流量（中圧主蒸気流量）を予測し、算出した中圧流量偏差ΔＦＭに補正係数ｋを乗算した中圧流量偏差補正値ｋΔＦＭがゼロとなるように中圧主蒸気流量を変化させるための高圧主蒸気圧力目標値を演算する。
制御装置２は、図６に示す、予め設定される中圧主蒸気圧力における特性線図（高圧特性線図）に基づいて高圧主蒸気圧力目標値を演算する。
中圧流量偏差ΔＦＭに乗算する補正係数ｋは、前記したように、予め設定される中圧設定値と中圧主蒸気圧力目標値との比であり、制御装置２は、補正係数ｋを中圧流量偏差ΔＦＭに乗算することによって、予め設定される中圧主蒸気圧力における高圧特性線図上の偏差を演算する。 Further, the control device 2 predicts the flow rate of the intermediate pressure main steam pipe 39 corresponding to the operation load of the gas turbine 11 and the currently set high pressure main steam pressure target value (medium pressure main steam flow rate) by the pressure calculator 300d. Then, a high pressure main steam pressure target value for changing the intermediate pressure main steam flow rate is calculated so that the intermediate pressure flow rate deviation correction value kΔFM obtained by multiplying the calculated intermediate pressure flow rate deviation ΔFM by the correction coefficient k is zero.
The control device 2 calculates a high-pressure main steam pressure target value based on a characteristic diagram (high-pressure characteristic diagram) at a preset intermediate-pressure main steam pressure shown in FIG.
As described above, the correction coefficient k by which the intermediate pressure flow rate deviation ΔFM is multiplied is the ratio between the preset intermediate pressure setting value and the intermediate pressure main steam pressure target value, and the control device 2 sets the correction coefficient k to the intermediate correction coefficient k. By multiplying the pressure flow deviation ΔFM, the deviation on the high pressure characteristic diagram at the preset intermediate pressure main steam pressure is calculated.

例えば、図６に示すように、ガスタービン１１の運転負荷が「Ｗ１」で、現在設定されている高圧主蒸気圧力目標値が「ＰＨ１」のとき、制御装置２は高圧特性線図に基づいて中圧主蒸気流量を「ＦＭ１」と予測する。
さらに、制御装置２は、中圧流量偏差補正値ｋΔＦＭが正の場合（つまり、中圧主蒸気流量の実測値が中圧許容最大流量より小さい場合）、中圧主蒸気流量の予測値である「ＦＭ１」よりもｋΔＦＭだけ高い「ＦＭ３」を中圧主蒸気流量とし、「ＦＭ３」に対応する高圧主蒸気圧力「ＰＨ３」を高圧主蒸気圧力目標値とする。一方、中圧流量偏差補正値ｋΔＦＭが負の場合（つまり、中圧主蒸気流量の実測値が中圧許容最大流量より大きい場合）、制御装置２は、中圧主蒸気流量の予測値である「ＦＭ１」よりもｋΔＦＭだけ低い「ＦＭ２」を中圧主蒸気流量とし、「ＦＭ２」に対応する高圧主蒸気圧力「ＰＨ２」を高圧主蒸気圧力目標値とする。
なお、高圧特性線図は、マップ形式であってもテーブル形式であっても関数形式であってもよく、制御装置２が参照できる形式であれば、そのデータ形式は限定されない。 For example, as shown in FIG. 6, when the operation load of the gas turbine 11 is “W1” and the currently set high-pressure main steam pressure target value is “PH1”, the control device 2 is based on the high-pressure characteristic diagram. The medium-pressure main steam flow rate is predicted as “FM1”.
Further, the control device 2 is the predicted value of the intermediate pressure main steam flow rate when the intermediate pressure flow rate deviation correction value kΔFM is positive (that is, when the measured value of the intermediate pressure main steam flow rate is smaller than the allowable intermediate pressure maximum flow rate). “FM3”, which is higher than “FM1” by kΔFM, is the medium-pressure main steam flow rate, and the high-pressure main steam pressure “PH3” corresponding to “FM3” is the high-pressure main steam pressure target value. On the other hand, when the intermediate pressure flow rate deviation correction value kΔFM is negative (that is, when the actual measurement value of the intermediate pressure main steam flow rate is larger than the intermediate pressure allowable maximum flow rate), the control device 2 is the predicted value of the intermediate pressure main steam flow rate. “FM2”, which is lower than “FM1” by kΔFM, is the medium-pressure main steam flow rate, and the high-pressure main steam pressure “PH2” corresponding to “FM2” is the high-pressure main steam pressure target value.
The high-voltage characteristic diagram may be a map format, a table format, or a function format, and the data format is not limited as long as the control device 2 can refer to it.

また、図５に示すように制御装置２は、高圧タービン入口圧力検出器２６が検出する高圧主蒸気圧力の実測値を、演算した高圧主蒸気圧力目標値から、減算器３００ｆで減算（高圧主蒸気圧力目標値−実測値）して高圧主蒸気圧偏差ΔＰＨを算出する。そして制御装置２は、例えば、ＰＩ動作器３００ｇでのＰＩ動作によって、高圧主蒸気圧偏差ΔＰＨをゼロとするように高圧タービンバイパス弁２３の開度を調節する。
高圧主蒸気圧偏差ΔＰＨが正のとき、高圧主蒸気圧力を高くするため制御装置２は高圧タービンバイパス弁２３を閉じる方向に調節し、高圧主蒸気圧偏差ΔＰＨが負のとき、高圧主蒸気圧力を低くするため制御装置２は高圧タービンバイパス弁２３を開く方向に調節する。
なお、蒸気タービン１０が停止していない場合、制御装置２は、圧力演算器３００ｄで演算した高圧主蒸気圧力目標値に替えて、予め設定される高圧主蒸気設定圧力を選択器３００ｅで選択し、高圧主蒸気設定圧力を高圧主蒸気圧力目標値とする。 Further, as shown in FIG. 5, the control device 2 subtracts the measured value of the high-pressure main steam pressure detected by the high-pressure turbine inlet pressure detector 26 from the calculated high-pressure main steam pressure target value by the subtractor 300f (high-pressure main pressure). The high-pressure main steam pressure deviation ΔPH is calculated by (steam pressure target value−actual value). And the control apparatus 2 adjusts the opening degree of the high-pressure turbine bypass valve 23 so that the high-pressure main steam pressure deviation ΔPH becomes zero by, for example, the PI operation in the PI operating unit 300g.
When the high-pressure main steam pressure deviation ΔPH is positive, the controller 2 adjusts the high-pressure turbine bypass valve 23 in the closing direction to increase the high-pressure main steam pressure, and when the high-pressure main steam pressure deviation ΔPH is negative, In order to lower the pressure, the control device 2 adjusts the high pressure turbine bypass valve 23 in the opening direction.
When the steam turbine 10 is not stopped, the control device 2 selects a preset high-pressure main steam set pressure with the selector 300e instead of the high-pressure main steam pressure target value calculated with the pressure calculator 300d. The high pressure main steam set pressure is set as the high pressure main steam pressure target value.

以上のような手順で制御装置２は、高圧タービンバイパス弁２３を制御して開度を調節し、高圧タービンバイパス管５１ａにおける高圧主蒸気の圧力を調節する。
図１に示す高圧タービンバイパス弁２３の開度が変化すると高圧ドラム２２の蒸発量が変化し、高圧過熱器５４ｊでの交換熱量（タービン排熱からの吸熱量）が変化する。これによって、高圧過熱器５４ｊの下流に備わる中圧蒸発器５４ｅを通過する排気ガスに含まれるタービン排熱の熱量が変化して中圧ドラム２１における復水の温度が変化し、これによって中圧ドラム２１の蒸発量が変化する。したがって、高圧タービンバイパス弁２３の開度を調節することによって中圧主蒸気管３９における中圧主蒸気流量を調節できる。 The control device 2 controls the high-pressure turbine bypass valve 23 to adjust the opening degree by the procedure as described above, and adjusts the pressure of the high-pressure main steam in the high-pressure turbine bypass pipe 51a.
When the opening degree of the high-pressure turbine bypass valve 23 shown in FIG. 1 changes, the evaporation amount of the high-pressure drum 22 changes, and the exchange heat amount (heat absorption amount from the turbine exhaust heat) in the high-pressure superheater 54j changes. As a result, the amount of heat of the turbine exhaust heat contained in the exhaust gas passing through the intermediate pressure evaporator 54e provided downstream of the high pressure superheater 54j changes, and the temperature of the condensate in the intermediate pressure drum 21 changes, thereby changing the intermediate pressure. The evaporation amount of the drum 21 changes. Therefore, the intermediate-pressure main steam flow rate in the intermediate-pressure main steam pipe 39 can be adjusted by adjusting the opening degree of the high-pressure turbine bypass valve 23.

《ガスタービン１１の運転負荷の調節》
制御装置２は、図７に示す機能ブロックを含んで構成されてガスタービン１１を制御する。図７に示すように制御装置２は、高圧主蒸気管４５（図１参照）に備わる高圧流量検出器４０１の検出値を高圧主蒸気管４５の高圧主蒸気流量の実測値とし、高圧主蒸気管４５に許容される高圧許容最大流量から高圧主蒸気流量の実測値を減算器４００ａで減算（高圧許容最大流量−実測値）して高圧流量偏差ΔＦＨを算出する。 << Adjustment of operation load of gas turbine 11 >>
The control device 2 is configured to include the functional blocks shown in FIG. 7 and controls the gas turbine 11. As shown in FIG. 7, the control device 2 uses the detected value of the high-pressure flow detector 401 provided in the high-pressure main steam pipe 45 (see FIG. 1) as an actual measurement value of the high-pressure main steam flow rate in the high-pressure main steam pipe 45. The actual value of the high-pressure main steam flow rate is subtracted by the subtractor 400a (high-pressure allowable maximum flow rate−actual value) from the high-pressure allowable maximum flow rate allowed in the pipe 45 to calculate the high-pressure flow rate deviation ΔFH.

また制御装置２は負荷演算器４００ｂで、選択器３００ｅ（図５参照）で選択される高圧主蒸気圧力目標値と、現在のガスタービン１１の運転負荷と、に基づいて図８に示す特性線図（タービン負荷特性線図）を参照し、高圧主蒸気圧力とガスタービン１１の運転負荷に対応する高圧主蒸気流量を予測する。
さらに制御装置２は負荷演算器４００ｂで、算出した高圧流量偏差ΔＦＨがゼロとなるように、タービン負荷特性線図の特性線上でガスタービン１１の運転負荷を変更する。 Further, the control device 2 is a load calculator 400b, which is a characteristic line shown in FIG. 8 based on the high pressure main steam pressure target value selected by the selector 300e (see FIG. 5) and the current operation load of the gas turbine 11. With reference to the figure (turbine load characteristic diagram), the high-pressure main steam flow corresponding to the high-pressure main steam pressure and the operation load of the gas turbine 11 is predicted.
Further, the control device 2 uses the load calculator 400b to change the operation load of the gas turbine 11 on the characteristic line of the turbine load characteristic diagram so that the calculated high-pressure flow deviation ΔFH becomes zero.

例えば図８に示すように、高圧主蒸気圧力目標値が「ＰＨ１」でガスタービン１１の運転負荷が「Ｗ１」の場合、タービン負荷特性線図に基づいて高圧主蒸気流量「ＦＨ１」が予測される。この場合に高圧流量偏差ΔＦＨが負のとき（すなわち、高圧主蒸気流量の実測値が高圧許容最大流量を超えているとき）、制御装置２は、高圧主蒸気流量が高圧流量偏差ΔＦＨに相当する量だけ「ＦＨ１」から低下した「ＦＨ２」と、高圧主蒸気圧力「ＰＨ１」を示す直線と、の交点となる運転負荷「Ｗ２」をガスタービン１１の運転負荷に設定する。一方、高圧流量偏差ΔＦＨが正のとき（すなわち、高圧主蒸気流量の実測値が高圧許容最大流量より低いとき）、制御装置２は、高圧主蒸気流量が高圧流量偏差ΔＦＨに相当する量だけ「ＦＨ１」から増加した「ＦＨ３」と、高圧主蒸気圧力「ＰＨ１」を示す直線と、の交点となる運転負荷「Ｗ３」をガスタービン１１の運転負荷に設定する。
制御装置２は、このように設定される運転負荷でガスタービン１１を運転することによって、算出した高圧流量偏差ΔＦＨをゼロにすることができる。なお、図６に示すように高圧主蒸気圧力が「ＰＨ２」または「ＰＨ３」になる場合、制御装置２は、「ＰＨ２」または「ＰＨ３」に対応するタービン負荷特性とするため、図８に示すようにタービン負荷特性線図を適宜変更する。 For example, as shown in FIG. 8, when the high pressure main steam pressure target value is “PH1” and the operation load of the gas turbine 11 is “W1”, the high pressure main steam flow rate “FH1” is predicted based on the turbine load characteristic diagram. The In this case, when the high-pressure flow deviation ΔFH is negative (that is, when the measured value of the high-pressure main steam flow exceeds the high-pressure allowable maximum flow rate), the control device 2 indicates that the high-pressure main steam flow corresponds to the high-pressure flow deviation ΔFH. The operating load “W2” that is the intersection of “FH2” that has decreased from “FH1” by the amount and the straight line that indicates the high-pressure main steam pressure “PH1” is set as the operating load of the gas turbine 11. On the other hand, when the high-pressure flow deviation ΔFH is positive (that is, when the actual measured value of the high-pressure main steam flow is lower than the high-pressure allowable maximum flow), the controller 2 determines that the high-pressure main steam flow is equal to the high-pressure flow deviation ΔFH. The operating load “W3” that is the intersection of “FH3” increased from “FH1” and the straight line indicating the high-pressure main steam pressure “PH1” is set as the operating load of the gas turbine 11.
The control device 2 can make the calculated high-pressure flow deviation ΔFH zero by operating the gas turbine 11 with the operation load set in this way. As shown in FIG. 6, when the high-pressure main steam pressure is “PH2” or “PH3”, the control device 2 has a turbine load characteristic corresponding to “PH2” or “PH3”. Thus, the turbine load characteristic diagram is appropriately changed.

さらに制御装置２は、現在の運転負荷（現在値）から、設定したガスタービン１１の運転負荷（設定値）を図７に示す減算器４００ｃで減算した偏差（負荷偏差ΔＷ）を演算し、選択器４００ｄから出力する。このとき、制御装置２は蒸気タービン１０が停止していない場合（つまり、ガスタービン１１と蒸気タービン１０がともに運転される通常運転の場合）、減算器４００ｃで演算する負荷偏差ΔＷに替えてゼロを選択器４００ｄで選択し、負荷偏差ΔＷをゼロとする。
そして、制御装置２は、選択器４００ｄから出力される負荷偏差ΔＷをガスタービン１１の運転負荷に対する負荷増減指令としてガスタービン１１の運転負荷を調節する。 Further, the control device 2 calculates and selects a deviation (load deviation ΔW) obtained by subtracting the set operating load (set value) of the gas turbine 11 by the subtractor 400c shown in FIG. 7 from the current operating load (current value). Output from the device 400d. At this time, when the steam turbine 10 is not stopped (that is, in the normal operation in which both the gas turbine 11 and the steam turbine 10 are operated), the control device 2 replaces the load deviation ΔW calculated by the subtractor 400c with zero. Is selected by the selector 400d, and the load deviation ΔW is set to zero.
Then, the control device 2 adjusts the operation load of the gas turbine 11 using the load deviation ΔW output from the selector 400d as a load increase / decrease command for the operation load of the gas turbine 11.

以上のように本実施形態に係る制御装置２（図１参照）は、ガスタービン１１（図１参照）を単独負荷運転する場合に、低圧タービンバイパス弁２５（図１参照）、中圧タービンバイパス弁２４（図１参照）、および、高圧タービンバイパス弁２３（図１参照）の弁開度と、ガスタービン１１の運転負荷と、を調節しながらＣ／Ｃ発電プラント１（図１参照）を運転する。   As described above, the control device 2 (see FIG. 1) according to the present embodiment performs the low-pressure turbine bypass valve 25 (see FIG. 1) and the intermediate-pressure turbine bypass when the gas turbine 11 (see FIG. 1) is operated with a single load. The C / C power plant 1 (see FIG. 1) is adjusted while adjusting the valve opening degree of the valve 24 (see FIG. 1) and the high-pressure turbine bypass valve 23 (see FIG. 1) and the operation load of the gas turbine 11. drive.

図９に示すように、本実施形態に係るガスタービン１１（図１参照）は、蒸気タービン１０（図１参照）が運転されている通常運転のときに第１負荷で運転される。そして、蒸気タービン１０の運転が停止してガスタービン１１が単独負荷運転する場合、蒸気タービン１０停止後の第１段階では排気ガスの温度が再熱器５４ｉ（図１参照）の耐熱温度を超えないように第２負荷が設定される。さらに第２段階として、低圧ドラム２０（図１参照）、中圧ドラム２１（図１参照）、および、高圧ドラム２２（図１参照）での蒸発量が、それぞれの許容最大蒸発量を超えないように第３負荷が調節される。   As shown in FIG. 9, the gas turbine 11 (see FIG. 1) according to the present embodiment is operated with the first load during the normal operation in which the steam turbine 10 (see FIG. 1) is operated. When the operation of the steam turbine 10 is stopped and the gas turbine 11 is operated with a single load, the temperature of the exhaust gas exceeds the heat resistance temperature of the reheater 54i (see FIG. 1) in the first stage after the stop of the steam turbine 10. The second load is set so as not to exist. Further, as a second stage, the evaporation amounts in the low pressure drum 20 (see FIG. 1), the intermediate pressure drum 21 (see FIG. 1), and the high pressure drum 22 (see FIG. 1) do not exceed the allowable maximum evaporation amounts. The third load is adjusted as follows.

このように本実施形態のＣ／Ｃ発電プラント１（図１参照）は、ガスタービン１１（図１参照）を単独負荷運転する場合に、図９に示すように運転負荷を段階的に切り替えることによって、蒸気が流入しない状態の再熱器５４ｉ（図１参照）が耐熱温度を超えて温度上昇することを防ぐとともに、低圧ドラム２０（図１参照）、中圧ドラム２１（図１参照）、および、高圧ドラム２２（図１参照）の蒸発量がそれぞれの許容最大蒸発量を超えることを防ぎ、さらに、可能な範囲で最大の運転負荷でガスタービン１１を単独負荷運転できる。   As described above, the C / C power plant 1 (see FIG. 1) of the present embodiment switches the operation load stepwise as shown in FIG. 9 when the gas turbine 11 (see FIG. 1) is operated with a single load. Prevents the reheater 54i (see FIG. 1) in the state where steam does not flow in from exceeding the heat-resistant temperature, and the low pressure drum 20 (see FIG. 1), the intermediate pressure drum 21 (see FIG. 1), In addition, it is possible to prevent the evaporation amount of the high-pressure drum 22 (see FIG. 1) from exceeding the allowable maximum evaporation amount, and further, the gas turbine 11 can be operated in a single load with the maximum operation load as much as possible.

また、高圧過熱器５４ｊ（図１参照）から排出される蒸気を、蒸気タービン１０（図１参照）を通ることなく再熱器５４ｉ（図１参照）に戻り蒸気として戻す配管がない構成のＣ／Ｃ発電プラント１（図１参照）であっても、ガスタービン１１（図１参照）が単独負荷運転する場合の再熱器５４ｉの温度上昇を耐熱温度以下に抑えることができる。したがって、戻り蒸気が再熱器５４ｉに流入しない構造のＣ／Ｃ発電プラント１であってもガスタービン１１を可能な範囲で最大の運転負荷で単独負荷運転できる。
そして、例えば新興国など、電力不足が懸念される地域において蒸気タービン１０が停止したときに可能な範囲で最大の運転負荷でガスタービン１１を単独負荷運転することによって、安定して電力を供給できる。
さらに、排熱回収ボイラ５４に脱硝装置９２が備わる構成によって、環境負荷低減や排熱回収ボイラ５４での熱回収による蒸気タービン１０の起動時間短縮を図ることができる。 Further, there is no pipe for returning the steam discharged from the high-pressure superheater 54j (see FIG. 1) to the reheater 54i (see FIG. 1) as steam without passing through the steam turbine 10 (see FIG. 1). Even in the case of the / C power plant 1 (see FIG. 1), the temperature rise of the reheater 54i when the gas turbine 11 (see FIG. 1) is operated with a single load can be suppressed to the heat resistant temperature or lower. Therefore, even in the C / C power plant 1 having a structure in which the return steam does not flow into the reheater 54i, the gas turbine 11 can be operated with a single load with the maximum operating load as much as possible.
And, for example, in an emerging country such as an emerging country, when the steam turbine 10 is stopped, the gas turbine 11 can be supplied with a maximum load so that the power can be stably supplied. .
Furthermore, the configuration in which the exhaust heat recovery boiler 54 includes the denitration device 92 can reduce the environmental load and shorten the startup time of the steam turbine 10 by recovering heat in the exhaust heat recovery boiler 54.

なお、排熱回収ボイラ５４をバイパスするようにバイパススタック（図示せず）および排気ガス切替ダンパ（図示せず）を備え、排気ガス切替ダンパをバイパススタック側に切り替えることでガスタービン１１（図１参照）の排気ガスを大気に放出してガスタービン１１を単独負荷運転する構成も考えられる。しかしながら、このような構成では、ガスタービン１１の排気ガスが大気に放出されて周囲環境に影響をおよぼすという問題がある。
本実施形態に係るＣ／Ｃ発電プラント１（図１参照）においては、ガスタービン１１の排気ガスは排熱回収ボイラ５４（図１参照）に取り込まれるため大気に放出されない。したがって周囲環境に影響をおよぼすことなくガスタービン１１を単独負荷運転できる。 A bypass stack (not shown) and an exhaust gas switching damper (not shown) are provided so as to bypass the exhaust heat recovery boiler 54, and the gas turbine 11 (FIG. 1) is switched by switching the exhaust gas switching damper to the bypass stack side. A configuration is also conceivable in which the gas turbine 11 is operated with a single load by discharging the exhaust gas of (see) to the atmosphere. However, in such a configuration, there is a problem that the exhaust gas of the gas turbine 11 is released to the atmosphere and affects the surrounding environment.
In the C / C power plant 1 (see FIG. 1) according to the present embodiment, the exhaust gas of the gas turbine 11 is taken into the exhaust heat recovery boiler 54 (see FIG. 1) and is not released to the atmosphere. Therefore, the gas turbine 11 can be operated with a single load without affecting the surrounding environment.

また、本実施形態に係るＣ／Ｃ発電プラント１は図１に示すように、低圧ドラム２０、中圧ドラム２１、および高圧ドラム２２の３つの蒸気ドラムを有する「三重圧排熱回収ボイラ」を含んで構成されるが、この構成に限定されない。１つ、または２つの蒸気ドラムを有するＣ／Ｃ発電プラントに本発明を適用することも可能であるし、４つ以上の蒸気ドラムを有するＣ／Ｃ発電プラントに本発明を適用することも可能である。
また、図１に示す多軸型のＣ／Ｃ発電プラント１に限定されず、ガスタービン１１と蒸気タービン１０とが１つの軸で直列に連結される発電プラントに本発明を適用することもできる。この場合、蒸気タービン１０に不具合が発生していない状態でガスタービン１１を単独負荷運転できる。 Further, as shown in FIG. 1, the C / C power plant 1 according to the present embodiment includes a “triple pressure exhaust heat recovery boiler” having three steam drums, a low pressure drum 20, an intermediate pressure drum 21, and a high pressure drum 22. However, it is not limited to this configuration. The present invention can be applied to a C / C power plant having one or two steam drums, and can also be applied to a C / C power plant having four or more steam drums. It is.
Further, the present invention is not limited to the multi-shaft type C / C power plant 1 shown in FIG. 1, and the present invention can also be applied to a power plant in which a gas turbine 11 and a steam turbine 10 are connected in series with one shaft. . In this case, the gas turbine 11 can be operated with a single load in a state where there is no malfunction in the steam turbine 10.

また、ガスタービン１１（図１参照）の排気ガスの温度は、大気温度の変動に応じて変化することから、例えば、ガスタービン１１の出力が同じであっても夏季と冬季とでは発生蒸気流量に差異が生じる。そこで、各タービンバイパス弁（高圧タービンバイパス弁２３（図１参照）、中圧タービンバイパス弁２４（図１参照）、低圧タービンバイパス弁２５（図１参照））を、蒸気流量ではなく大気温度に基づいて補正する構成としてもよい。   Further, since the temperature of the exhaust gas of the gas turbine 11 (see FIG. 1) changes according to the change in the atmospheric temperature, for example, even if the output of the gas turbine 11 is the same, the generated steam flow rate in summer and winter There will be a difference. Therefore, each turbine bypass valve (the high pressure turbine bypass valve 23 (see FIG. 1), the intermediate pressure turbine bypass valve 24 (see FIG. 1), and the low pressure turbine bypass valve 25 (see FIG. 1)) is set to the atmospheric temperature instead of the steam flow rate. It is good also as a structure correct | amended based on.

また、ガスタービン１１（図１参照）の運転負荷の目標値と、この目標値に基づいて熱バランス計算によって求められた各タービンバイパス弁の設定値と、を固定値とする構成としてもよい。この場合、ガスタービン１１の運転負荷の目標値は低めに設定されることが好ましい。   Moreover, it is good also as a structure which makes the fixed value the target value of the operation load of the gas turbine 11 (refer FIG. 1), and the setting value of each turbine bypass valve calculated | required by heat balance calculation based on this target value. In this case, the target value of the operation load of the gas turbine 11 is preferably set to be low.

１ Ｃ／Ｃ発電プラント（コンバインドサイクル型発電プラント）
１０ 蒸気タービン
１１ ガスタービン
１２ 高圧タービン
１３ 中圧タービン
１４ 低圧タービン
１５ 復水器
２０ 低圧ドラム
２１ 中圧ドラム
２２ 高圧ドラム
２３ 高圧タービンバイパス弁（高圧主蒸気圧力調節手段）
２４ 中圧タービンバイパス弁（中圧主蒸気圧力調節手段）
２５ 低圧タービンバイパス弁（低圧主蒸気圧力調節手段）
５１ａ 高圧タービンバイパス管
５２ａ 中圧タービンバイパス管
５３ 低圧タービンバイパス管
５４ 排熱回収ボイラ
５４ｉ 再熱器
５４ｊ 高圧過熱器 1 C / C power plant (combined cycle power plant)
DESCRIPTION OF SYMBOLS 10 Steam turbine 11 Gas turbine 12 High pressure turbine 13 Medium pressure turbine 14 Low pressure turbine 15 Condenser 20 Low pressure drum 21 Medium pressure drum 22 High pressure drum 23 High pressure turbine bypass valve (high pressure main steam pressure adjustment means)
24 Medium pressure turbine bypass valve (Medium pressure main steam pressure adjusting means)
25 Low pressure turbine bypass valve (Low pressure main steam pressure adjusting means)
51a High-pressure turbine bypass pipe 52a Medium-pressure turbine bypass pipe 53 Low-pressure turbine bypass pipe 54 Waste heat recovery boiler 54i Reheater 54j High-pressure superheater

Claims (4)

ガスタービンと、
前記ガスタービンの排気ガスに含まれる排熱を利用して発生する高圧主蒸気で駆動する高圧タービン、前記排熱を利用して発生する中圧主蒸気で駆動する中圧タービン、および、前記排熱を利用して発生する低圧主蒸気で駆動する低圧タービンを含んでなる蒸気タービンと、
前記高圧タービンから排出される前記高圧主蒸気を凝縮して復水を発生する復水器と、
前記復水器で発生する前記復水を前記排熱で過熱する排熱回収ボイラと、
前記排熱回収ボイラで過熱された前記復水で前記高圧主蒸気を発生する高圧ドラムと、
前記高圧ドラムで発生する前記高圧主蒸気を前記高圧タービンをバイパスして前記復水器に導入する高圧タービンバイパス管および当該高圧タービンバイパス管における前記高圧主蒸気の圧力を調節して前記高圧主蒸気を前記復水器へ導入する高圧主蒸気圧力調節手段と、を含んで構成され、
前記排熱回収ボイラに、
前記高圧ドラムで発生する前記高圧主蒸気を前記排熱で過熱する高圧過熱器と、
前記高圧タービンから排気される前記高圧主蒸気を前記排熱で過熱する再熱器と、が、前記排気ガスの流れに対する上流からこの順に配置されるコンバインドサイクル型発電プラントであって、
前記蒸気タービンが停止したときに、
前記高圧ドラムで発生する前記高圧主蒸気を前記高圧タービンバイパス管で前記復水器に導入し、前記高圧主蒸気圧力調節手段で前記高圧主蒸気を減圧することで、当該高圧ドラムの蒸発量を増やして前記高圧過熱器における前記排熱の吸熱量を増やすとともに、
前記高圧ドラムの蒸発量が当該高圧ドラムの許容最大蒸発量を超えないように前記高圧タービンバイパス管における前記高圧主蒸気の圧力を調節し、
さらに、前記高圧過熱器で吸熱された後の前記排気ガスに含まれる前記排熱で前記再熱器が耐熱許容値を超えて高温にならないように前記ガスタービンの運転負荷を調節して前記ガスタービンを単独で運転可能であること、を特徴とするコンバインドサイクル型発電プラント。 A gas turbine,
A high-pressure turbine driven by high-pressure main steam generated using exhaust heat contained in the exhaust gas of the gas turbine, an intermediate-pressure turbine driven by medium-pressure main steam generated using the exhaust heat, and the exhaust A steam turbine comprising a low pressure turbine driven by low pressure main steam generated using heat;
A condenser for condensing the high-pressure main steam discharged from the high-pressure turbine to generate condensate;
An exhaust heat recovery boiler that superheats the condensate generated in the condenser with the exhaust heat;
A high-pressure drum that generates the high-pressure main steam from the condensate superheated by the exhaust heat recovery boiler;
The high-pressure main steam generated in the high-pressure drum bypasses the high-pressure turbine and is introduced into the condenser, and the pressure of the high-pressure main steam in the high-pressure turbine bypass pipe is adjusted to adjust the high-pressure main steam. High pressure main steam pressure adjusting means for introducing the gas into the condenser,
In the exhaust heat recovery boiler,
A high-pressure superheater that superheats the high-pressure main steam generated in the high-pressure drum with the exhaust heat;
A reheater that superheats the high-pressure main steam exhausted from the high-pressure turbine with the exhaust heat, is a combined cycle type power plant arranged in this order from the upstream with respect to the flow of the exhaust gas,
When the steam turbine stops,
The high-pressure main steam generated in the high-pressure drum is introduced into the condenser through the high-pressure turbine bypass pipe, and the high-pressure main steam pressure is reduced by the high-pressure main steam pressure adjusting means, thereby reducing the evaporation amount of the high-pressure drum. While increasing the heat absorption amount of the exhaust heat in the high-pressure superheater,
Adjusting the pressure of the high-pressure main steam in the high-pressure turbine bypass pipe so that the evaporation amount of the high-pressure drum does not exceed the allowable maximum evaporation amount of the high-pressure drum,
Further, the gas turbine is adjusted by adjusting an operation load of the gas turbine so that the exhaust heat contained in the exhaust gas after being absorbed by the high-pressure superheater does not exceed a heat-resistant allowable value and does not reach a high temperature. A combined cycle power plant characterized by being capable of operating a turbine alone. 前記中圧主蒸気を発生する中圧ドラムと、
前記中圧ドラムで発生する前記中圧主蒸気を前記中圧タービンをバイパスして前記復水器に導入する中圧タービンバイパス管および当該中圧タービンバイパス管における前記中圧主蒸気の圧力を調節して前記中圧主蒸気を前記復水器へ導入する中圧主蒸気圧力調節手段と、
前記低圧主蒸気を発生する低圧ドラムと、
前記低圧ドラムで発生する前記低圧主蒸気を前記低圧タービンをバイパスして前記復水器に導入する低圧タービンバイパス管および当該低圧タービンバイパス管における前記低圧主蒸気の圧力を調節して前記低圧主蒸気を前記復水器へ導入する低圧主蒸気圧力調節手段と、をさらに備え、
前記蒸気タービンが停止したときに、
前記中圧ドラムで発生する前記中圧主蒸気を前記中圧タービンバイパス管で前記復水器に導入し、前記中圧主蒸気圧力調節手段で前記中圧主蒸気を減圧することで、当該中圧ドラムの蒸発量を増やすとともに、前記中圧ドラムの蒸発量が当該中圧ドラムの許容最大蒸発量を超えないように前記中圧タービンバイパス管における前記中圧主蒸気の圧力を調節し、
前記低圧ドラムで発生する前記低圧主蒸気を前記低圧タービンバイパス管で前記復水器に導入し、前記低圧主蒸気圧力調節手段で前記低圧主蒸気を減圧することで、当該低圧ドラムの蒸発量を増やすとともに、前記低圧ドラムの蒸発量が当該低圧ドラムの許容最大蒸発量を超えないように前記低圧タービンバイパス管における前記低圧主蒸気の圧力を調節することを特徴とする請求項１に記載のコンバインドサイクル型発電プラント。 An intermediate pressure drum for generating the intermediate pressure main steam;
An intermediate pressure turbine bypass pipe for introducing the intermediate pressure main steam generated in the intermediate pressure drum into the condenser bypassing the intermediate pressure turbine, and adjusting the pressure of the intermediate pressure main steam in the intermediate pressure turbine bypass pipe Medium pressure main steam pressure adjusting means for introducing the medium pressure main steam into the condenser;
A low-pressure drum that generates the low-pressure main steam;
The low-pressure main steam generated in the low-pressure drum bypasses the low-pressure turbine and is introduced into the condenser, and the pressure of the low-pressure main steam in the low-pressure turbine bypass pipe is adjusted to adjust the low-pressure main steam. And a low-pressure main steam pressure adjusting means for introducing into the condenser,
When the steam turbine stops,
The intermediate pressure main steam generated in the intermediate pressure drum is introduced into the condenser through the intermediate pressure turbine bypass pipe, and the intermediate pressure main steam is reduced by the intermediate pressure main steam pressure adjusting means. While increasing the evaporation amount of the pressure drum, adjusting the pressure of the intermediate pressure main steam in the intermediate pressure turbine bypass pipe so that the evaporation amount of the intermediate pressure drum does not exceed the allowable maximum evaporation amount of the intermediate pressure drum,
The low-pressure main steam generated in the low-pressure drum is introduced into the condenser through the low-pressure turbine bypass pipe, and the low-pressure main steam pressure adjusting means depressurizes the low-pressure main steam, thereby reducing the evaporation amount of the low-pressure drum. The combined pressure according to claim 1, wherein the pressure of the low-pressure main steam in the low-pressure turbine bypass pipe is adjusted so that the evaporation amount of the low-pressure drum does not exceed an allowable maximum evaporation amount of the low-pressure drum. Cycle power plant. ガスタービンと、
前記ガスタービンの排気ガスに含まれる排熱を利用して発生する高圧主蒸気で駆動する高圧タービン、前記排熱を利用して発生する中圧主蒸気で駆動する中圧タービン、および、前記排熱を利用して発生する低圧主蒸気で駆動する低圧タービンを含んでなる蒸気タービンと、
前記高圧タービンから排出される前記高圧主蒸気を凝縮して復水を発生する復水器と、
前記復水器で発生する前記復水を前記排熱で過熱する排熱回収ボイラと、
前記排熱回収ボイラで過熱された前記復水で前記高圧主蒸気を発生する高圧ドラムと、
前記高圧ドラムで発生する前記高圧主蒸気を前記高圧タービンをバイパスして前記復水器に導入する高圧タービンバイパス管および当該高圧タービンバイパス管における前記高圧主蒸気の圧力を調節して前記高圧主蒸気を前記復水器へ導入する高圧主蒸気圧力調節手段と、を含んで構成され、
前記排熱回収ボイラに、
前記高圧ドラムで発生する前記高圧主蒸気を過熱する高圧過熱器と、
前記高圧タービンから排気される前記高圧主蒸気を前記排熱で過熱する再熱器と、が、前記排気ガスの流れに対する上流からこの順に配置されるコンバインドサイクル型発電プラントで前記ガスタービンを単独で運転する運転方法であって、
前記高圧過熱器における前記排熱の吸熱量を増やすために前記高圧ドラムの蒸発量を増やすとともに、前記高圧ドラムの蒸発量が当該高圧ドラムの許容最大蒸発量を超えないように前記高圧主蒸気圧力調節手段を介して前記高圧タービンバイパス管における前記高圧主蒸気の圧力を調節する手順と、
前記高圧過熱器で吸熱された後の前記排気ガスに含まれる前記排熱で前記再熱器が耐熱許容値を超えて高温にならないように前記ガスタービンの運転負荷を調節する手順と、を有することを特徴とする運転方法。 A gas turbine,
A high-pressure turbine driven by high-pressure main steam generated using exhaust heat contained in the exhaust gas of the gas turbine, an intermediate-pressure turbine driven by medium-pressure main steam generated using the exhaust heat, and the exhaust A steam turbine comprising a low pressure turbine driven by low pressure main steam generated using heat;
A condenser for condensing the high-pressure main steam discharged from the high-pressure turbine to generate condensate;
An exhaust heat recovery boiler that superheats the condensate generated in the condenser with the exhaust heat;
A high-pressure drum that generates the high-pressure main steam from the condensate superheated by the exhaust heat recovery boiler;
The high-pressure main steam generated in the high-pressure drum bypasses the high-pressure turbine and is introduced into the condenser, and the pressure of the high-pressure main steam in the high-pressure turbine bypass pipe is adjusted to adjust the high-pressure main steam. High pressure main steam pressure adjusting means for introducing the gas into the condenser,
In the exhaust heat recovery boiler,
A high-pressure superheater that superheats the high-pressure main steam generated in the high-pressure drum;
A reheater that superheats the high-pressure main steam exhausted from the high-pressure turbine with the exhaust heat, and the gas turbine alone in a combined cycle power plant arranged in this order from the upstream with respect to the flow of the exhaust gas. A driving method for driving,
The high pressure main steam pressure is increased so that the amount of evaporation of the high pressure drum is increased in order to increase the heat absorption amount of the exhaust heat in the high pressure superheater, and the amount of evaporation of the high pressure drum does not exceed the allowable maximum amount of evaporation of the high pressure drum. Adjusting the pressure of the high-pressure main steam in the high-pressure turbine bypass pipe via adjusting means;
Adjusting the operating load of the gas turbine so that the reheater does not exceed a heat-resistant allowable value due to the exhaust heat contained in the exhaust gas after being absorbed by the high-pressure superheater. A driving method characterized by that. 前記中圧主蒸気を発生する中圧ドラムと、
前記中圧ドラムで発生する前記中圧主蒸気を前記中圧タービンをバイパスして前記復水器に導入する中圧タービンバイパス管および当該中圧タービンバイパス管における前記中圧主蒸気の圧力を調節して前記中圧主蒸気を前記復水器へ導入する中圧主蒸気圧力調節手段と、
前記低圧主蒸気を発生する低圧ドラムと、
前記低圧ドラムで発生する前記低圧主蒸気を前記低圧タービンをバイパスして前記復水器に導入する低圧タービンバイパス管および当該低圧タービンバイパス管における前記低圧主蒸気の圧力を調節して前記低圧主蒸気を前記復水器へ導入する低圧主蒸気圧力調節手段と、が備わる前記コンバインドサイクル型発電プラントにおいて、
前記中圧ドラムの蒸発量が当該中圧ドラムの許容最大蒸発量を超えないように前記中圧主蒸気圧力調節手段を介して前記中圧タービンバイパス管における前記中圧主蒸気の圧力を調節する手順と、
前記低圧ドラムの蒸発量が当該低圧ドラムの許容最大蒸発量を超えないように前記低圧主蒸気圧力調節手段を介して前記低圧タービンバイパス管における前記低圧主蒸気の圧力を調節する手順と、
を備えることを特徴とする請求項３に記載の運転方法。 An intermediate pressure drum for generating the intermediate pressure main steam;
An intermediate pressure turbine bypass pipe for introducing the intermediate pressure main steam generated in the intermediate pressure drum into the condenser bypassing the intermediate pressure turbine, and adjusting the pressure of the intermediate pressure main steam in the intermediate pressure turbine bypass pipe Medium pressure main steam pressure adjusting means for introducing the medium pressure main steam into the condenser;
A low-pressure drum that generates the low-pressure main steam;
The low-pressure main steam generated in the low-pressure drum bypasses the low-pressure turbine and is introduced into the condenser, and the pressure of the low-pressure main steam in the low-pressure turbine bypass pipe is adjusted to adjust the low-pressure main steam. In the combined cycle type power plant, comprising a low-pressure main steam pressure adjusting means for introducing the water into the condenser,
The pressure of the intermediate pressure main steam in the intermediate pressure turbine bypass pipe is adjusted via the intermediate pressure main steam pressure adjusting means so that the evaporation amount of the intermediate pressure drum does not exceed the allowable maximum evaporation amount of the intermediate pressure drum. Procedure and
Adjusting the pressure of the low-pressure main steam in the low-pressure turbine bypass pipe via the low-pressure main steam pressure adjusting means so that the evaporation amount of the low-pressure drum does not exceed the allowable maximum evaporation amount of the low-pressure drum;
The operation method according to claim 3, further comprising:
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