JPS6237721B2 - - Google Patents
Info
- Publication number
- JPS6237721B2 JPS6237721B2 JP16275079A JP16275079A JPS6237721B2 JP S6237721 B2 JPS6237721 B2 JP S6237721B2 JP 16275079 A JP16275079 A JP 16275079A JP 16275079 A JP16275079 A JP 16275079A JP S6237721 B2 JPS6237721 B2 JP S6237721B2
- Authority
- JP
- Japan
- Prior art keywords
- flow rate
- main steam
- signal
- drum level
- steam flow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Control Of Non-Electrical Variables (AREA)
- Control Of Steam Boilers And Waste-Gas Boilers (AREA)
Description
【発明の詳細な説明】
本発明は、負荷の急激な変化時にボイラのドラ
ムレベルを安定に制御するドラムレベル制御装置
に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drum level control device that stably controls the drum level of a boiler during sudden changes in load.
従来技術による制御系統を第１図に示す。ドラ
ムレベル信号１は比例演算器７、積分演算器８お
よび加算器９よりなるPI制御器に加えられ、加算
器１０において主蒸気流量信号２と加算され、給
水設定値４となる。給水設定値４と給水流量信号
３は減算器１１において減算され、その偏差であ
る給水偏差信号５は、比例演算器１２、積分器１
３および加算器１４よりなるPI制御器に加えら
れ、給水弁開度指令６として出力される。 FIG. 1 shows a control system according to the prior art. The drum level signal 1 is applied to a PI controller consisting of a proportional calculator 7, an integral calculator 8 and an adder 9, and is added to the main steam flow rate signal 2 in the adder 10, resulting in a feed water set value 4. The water supply setting value 4 and the water supply flow rate signal 3 are subtracted in a subtractor 11, and the deviation therefrom, the water supply deviation signal 5, is obtained by a proportional calculator 12 and an integrator 1.
3 and an adder 14, and outputted as a water supply valve opening command 6.
負荷が急激に降下する場合を例にとり、第２図
に主蒸気流量信号２と、給水流量信号３の比較を
示し、第３図に、その時のドラムレベルの変動状
況を示す。第３図に示すように、ドラムレベルは
負荷が急激に降下を始めると、逆応答によりレベ
ルが一旦低下し、その後レベルは上昇し、負荷変
化終了と同時に、逆応答によつてレベルは急激に
上昇する。 Taking as an example the case where the load suddenly drops, FIG. 2 shows a comparison between the main steam flow rate signal 2 and the feed water flow rate signal 3, and FIG. 3 shows the fluctuation state of the drum level at that time. As shown in Figure 3, when the load starts to drop rapidly, the drum level drops temporarily due to the reverse response, then the level rises, and as soon as the load change ends, the level suddenly decreases due to the reverse response. Rise.
給水流量指令信号は、前述のように、主蒸気流
量信号２と、給水流量信号３との偏差により与え
られるが、負荷変化中は給水流量の応答が主蒸気
流量よりも遅いために、第２図に示すように給水
流量が主蒸気流量に比べて過剰となり、ドラムレ
ベルが上昇するという欠点があつた。 As mentioned above, the feedwater flow rate command signal is given by the deviation between the main steam flow rate signal 2 and the feedwater flow rate signal 3. However, during load changes, the response of the feedwater flow rate is slower than the main steam flow rate, so the second As shown in the figure, the water supply flow rate was excessive compared to the main steam flow rate, causing the drum level to rise.
また、急激な負荷変化のない場合には、従来の
ように、ドラムレベル制御ゲインを固定しておい
ても問題はなかつたが、急激な負荷変化が発生し
た場合には、負荷変化中にはゲインが大き過ぎて
安定な制御が得られないという欠点があつた。 In addition, if there are no sudden load changes, there is no problem even if the drum level control gain is fixed as in the past, but if a sudden load change occurs, The drawback was that the gain was too large and stable control could not be obtained.
本発明の目的は急激な負荷変化中でもドラムレ
ベルを安定に制御することのできる制御装置を提
供することにある。 SUMMARY OF THE INVENTION An object of the present invention is to provide a control device that can stably control a drum level even during rapid load changes.
本発明の特徴は、ドラム型ボイラの急激な負荷
変化時に、主蒸気流量と、遅れて応答する給水流
量との偏差をなくすために、主蒸気流量の検出信
号の微分値を主蒸気流量信号に加算して見かけの
主蒸気流量信号を作り、これを用いて給水弁を早
く開閉させるようにし、また負荷変化時には、ド
ラムレベルの制御ゲインを下げることにより、ド
ラムレベルを安定に制御できるようにしたもので
ある。 The feature of the present invention is to use the differential value of the detection signal of the main steam flow rate as the main steam flow rate signal in order to eliminate the deviation between the main steam flow rate and the feed water flow rate that responds with a delay during a sudden load change of a drum boiler. By adding the signals, an apparent main steam flow rate signal is created, and this is used to open and close the water supply valve quickly. Also, when the load changes, the drum level control gain is lowered to ensure stable control of the drum level. It is something.
以下、本発明の実施例を、第４図を参照して説
明する。第１図との比較から明らかなように、本
実施例では、第１図の回路に変化率制限器１９、
乗算器２０，２１、微分回路２３および加算器２
４が付加されている。また、図から明らかなよう
に、本発明の給水制御系は、ドラムレベル制御PI
と給水弁制御PIを持つカスケード制御である。主
蒸気流量信号２を微分回路２３に供給し、加算器
２４において微分出力（変化率）を主蒸気流量信
号に加えて得られる信号を見かけの主蒸気流量信
号２′とする。給水弁開度指令信号６は、見かけ
の主蒸気流量信号２′およびドラムレベル信号１
のPI演算結果の和である給水設定値４と給水流量
信号３との偏差により作られる。 Embodiments of the present invention will be described below with reference to FIG. As is clear from the comparison with FIG. 1, in this embodiment, the rate of change limiter 19 is added to the circuit of FIG.
Multipliers 20, 21, differentiation circuit 23 and adder 2
4 is added. Furthermore, as is clear from the figure, the water supply control system of the present invention has a drum level control PI.
It is a cascade control with and water valve control PI. The main steam flow rate signal 2 is supplied to the differentiating circuit 23, and the differential output (rate of change) is added to the main steam flow rate signal in the adder 24, and the resulting signal is defined as the apparent main steam flow rate signal 2'. The water supply valve opening command signal 6 is based on the apparent main steam flow rate signal 2' and the drum level signal 1.
It is created by the deviation between the water supply setting value 4, which is the sum of the PI calculation results, and the water supply flow rate signal 3.
第４図の構成によつて得られる給水弁開度指令
信号６は、明らかなように、微分回路２３を付加
しないときに比べ、負荷下降時には弁を早く絞り
込み、また負荷上昇時には弁を早く開くように作
用するので、給水流量と実主蒸流量との偏差をな
くして、レベルの変動を安定に制御することを可
能とする。 As is clear, the water supply valve opening command signal 6 obtained by the configuration shown in FIG. 4 narrows the valve earlier when the load is decreasing, and opens the valve earlier when the load increases, compared to when the differential circuit 23 is not added. Therefore, it is possible to eliminate the deviation between the water supply flow rate and the actual main vapor flow rate, and to stably control level fluctuations.
第５図は、本発明を適用した場合の主蒸気流
量、給水流量信号の変化状況を示す図で、主蒸気
流量信号２に微分回路の出力を加算した見かけの
主蒸気流量信号２′と給水流量３とがほぼ一致し
ていることを示している。 FIG. 5 is a diagram showing changes in the main steam flow rate and feed water flow rate signals when the present invention is applied. It is shown that the flow rate 3 is almost the same.
第６図には、この時のドラムレベルの変動を示
し、曲線２７は負荷変化中もドラムレベル制御系
のゲインを一定にした場合の変動、曲線２８はゲ
インを下げた時の変動を示す。第６図から明らか
なように、負荷変動巾はドラム制御系のゲインを
小さくした方がレベル変動が小さくなる。このた
めに、第４図に示した本発明の実施例では、負荷
の変化率が予定値を超えた場合にはドラムレベル
制御ゲインを下げる回路を含んでいる。すなわ
ち、負荷変化率が設定値よりも大きくなつた場合
には変化率制限器１９が出力を生じ、乗算器２
０，２１にゲイン下げ指令信号２２を送り、比例
演算器７、積分演算器８および加算器９よりなる
PI制御器のゲインを下げる。 FIG. 6 shows the fluctuation of the drum level at this time, with curve 27 showing the fluctuation when the gain of the drum level control system is kept constant even during load changes, and curve 28 showing the fluctuation when the gain is lowered. As is clear from FIG. 6, the level fluctuation becomes smaller when the gain of the drum control system is made smaller. To this end, the embodiment of the present invention shown in FIG. 4 includes a circuit that reduces the drum level control gain when the rate of change in load exceeds a predetermined value. That is, when the load change rate becomes larger than the set value, the change rate limiter 19 produces an output, and the multiplier 2
It sends a gain reduction command signal 22 to 0 and 21, and consists of a proportional calculator 7, an integral calculator 8, and an adder 9.
Decrease the gain of the PI controller.
以上に詳述したように本発明のドラムレベル制
御装置によれば、負荷の急激な変化時に、制御の
難しいドラムレベルを安定に保持できる効果があ
る。 As described above in detail, the drum level control device of the present invention has the effect of stably maintaining the drum level, which is difficult to control, even when the load changes rapidly.
第１図は従来技術によるドラムレベル制御装置
のブロツク図、第２図は従来装置における主蒸気
流量信号と給水流量信号との関係を示す図、第３
図はその場合のドラムレベルの変動を示す図、第
４図本発明の一実施例のブロツク図、第５図は本
発明の実施例における主蒸気流量信号と給水流量
信号との関係を示す図、第６図はその場合のドラ
ムレベルの変動を示す図である。
１…ドラムレベル信号、２…主蒸気流量信号、
３…給水流量信号、６…給水弁開度指令、７，１
２…比例演算器、８，１３…積分器、１９…変化
率制限器、２０，２１…乗算器、２３…微分回
路。
Fig. 1 is a block diagram of a drum level control device according to the prior art, Fig. 2 is a diagram showing the relationship between the main steam flow rate signal and the feed water flow rate signal in the conventional device, and Fig. 3
Fig. 4 is a block diagram of an embodiment of the present invention, and Fig. 5 is a diagram showing the relationship between the main steam flow rate signal and the feed water flow rate signal in the embodiment of the present invention. , FIG. 6 is a diagram showing the fluctuation of the drum level in that case. 1...Drum level signal, 2...Main steam flow rate signal,
3... Water supply flow rate signal, 6... Water supply valve opening command, 7, 1
2... Proportional calculator, 8, 13... Integrator, 19... Rate of change limiter, 20, 21... Multiplier, 23... Differential circuit.
Claims (1)
制御PIとによりカスケード制御するようにしたド
ラムレベル制御装置に於いて、主蒸気流量信号を
微分回路に供給し、負荷変化中は主蒸気流量信号
の変化率を主蒸気流量信号に加えて見かけの主蒸
気流量信号を作り、これと前記ドラムレベル制御
PI演算結果との和及び給水流量信号との差をと
り、これらの結果に基づいて給水弁の開度を制御
することを特徴とするドラムレベル制御装置。 ２ 主蒸気流量信号の変化率が予定値以上となつ
た場合には、ドラムレベル制御PIのゲインを下げ
る手段をさらに具備したことを特徴とする特許請
求の範囲第１項記載のドラムレベル制御装置。[Claims] 1. In a drum level control device in which the feed water flow rate is cascade controlled by a drum level control PI and a feed water flow rate control PI, a main steam flow rate signal is supplied to a differentiating circuit, adds the rate of change of the main steam flow signal to the main steam flow signal to create an apparent main steam flow signal, which is combined with the drum level control
A drum level control device characterized by calculating the sum of the PI calculation result and the difference between the water supply flow rate signal and controlling the opening degree of the water supply valve based on these results. 2. The drum level control device according to claim 1, further comprising means for lowering the gain of the drum level control PI when the rate of change of the main steam flow rate signal exceeds a predetermined value. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16275079A JPS5687703A (en) | 1979-12-17 | 1979-12-17 | Controller for level of drum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16275079A JPS5687703A (en) | 1979-12-17 | 1979-12-17 | Controller for level of drum |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5687703A JPS5687703A (en) | 1981-07-16 |
| JPS6237721B2 true JPS6237721B2 (en) | 1987-08-13 |
Family
ID=15760541
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16275079A Granted JPS5687703A (en) | 1979-12-17 | 1979-12-17 | Controller for level of drum |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5687703A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56135195A (en) * | 1980-03-27 | 1981-10-22 | Tokyo Shibaura Electric Co | Adjustment forecast feedwater control device of atomic power plant |
| JPH0686922B2 (en) * | 1984-08-17 | 1994-11-02 | 株式会社日立製作所 | Boiler drum level controller |
| JPS6166005A (en) * | 1984-09-10 | 1986-04-04 | バブコツク日立株式会社 | Boiler drum water-level controller |
| US7053341B2 (en) * | 2004-02-12 | 2006-05-30 | General Electric Company | Method and apparatus for drum level control for drum-type boilers |
-
1979
- 1979-12-17 JP JP16275079A patent/JPS5687703A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5687703A (en) | 1981-07-16 |
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