11 COMPRESSOR CONTROLS壓縮機控制11.1 GENERAL DESCRIPTION概述11.1.1 Antisurge Control System反喘振控制系統The antisurge control system prevents compressor surge by recycling process gas, reducing head and increasing flow through the compressor.反喘振控制系統通過循環處理氣，減少壓差和增加流過壓縮機的流量來防止壓縮機喘振。The antisurge control system consists of pressure transmitters and temperature detectors at the suction and discharge sides of the compressor, a flow transmitter across the suction line orifice, an algorithm in the control system, and a recycle control valve with accessories.反喘振控制系統由壓縮機入口和出口側的壓力變送器和溫度探測器，入口管線上有一個流量變送器，控制系統里的一個運算法則，和一個再循環控制閥及其附件。When conditions fall below the surge protection margin, the control system opens the recycle valve. When conditions return to greater than the surge protection margin, the control system closes the recycle valve. Figure 11.1.1 is an antisurge system diagram.當條件降到喘振保護極限，控制系統打開再循環閥。當條件回到大于喘振保護極限，控制系統關閉再循環閥。圖11.1.1是一個反喘振系統圖。Figure 11.1.1 Antisurge Control System Diagram圖11.1.1反喘振控制系統圖View graphic看圖SURGE DETECTOR喘振探測器Rapid decreases in compressor flow indicate compressor surge. The surge detector in the antisurge system monitors flow through the compressor and counts flow rate pulses. A pulse is a 25 percent decrease in flow. Each pulse opens the recycle valve 15 percent. Five pulses in ten seconds shuts down the engine.壓縮機流量迅速減少顯示壓縮機喘振。反喘振系統里的喘振探測器監視流過壓縮機的流量和計算流度脈沖。一個脈沖是25%的流量減少。每個脈沖打開再循環閥15%。十秒五個脈沖將關閉引擎。11.1.2 Process Control System過程控制系統Process control maintains control parameter(s) at selected setpoint(s) by modifying the turbines gas producer speed (Ngp), and if necessary by opening the recycle valve.過程控制通過修改透平壓氣機的速度(Ngp)來在選擇的設定點維護控制參數，如果需要打開再循環閥。The three-loop process control system regulates engine speed and recycle valve position to control suction pressure, discharge pressure, and suction flow process variables. The antisurge system works with process control and overrides it when necessary.三回路過程控制系統調節引擎速度和再循環閥位置來控制入口壓力，出口壓力，和入口流量工藝參數。反喘振系統可過程控制一起運行，必要時優先于過程控制。For settings and operating design values not discussed in this chapter refer to the Balance of Plant Specification.設置和操作的設計值在本章節內沒有進行討論，查閱設備平衡規范。11.2 FUNCTIONAL DESCRIPTION功能描述11.2.1 Antisurge Control System反喘振控制系統MEASURED PARAMETERS測量參數The antisurge system monitors:反喘振系統監控： Pressure drop across a flow measuring element (hw)流量測量元件的壓力(hw) Suction and discharge pressures (P2 and P1)入口和出口壓力(P2 和 P1) Suction and discharge temperatures (T2 and T1)入口和出口溫度(T2 和 T1)THE SURGE LIMIT MODEL喘振限制模型The compressors surge limit is modeled over the compressors operating speed. 在壓縮機運行速度上建立壓縮機喘振限制模型。The Y-axis and X-axis are (P2 / P1)(n-1)/n)-1 / (n-1) / n versus hw/P11/2. The foregoing are termed reduced head and reduced flow as the common factors (T, Z, and SG) in the head and flow calculation equations are cancelled.Y軸和X軸是(P2 / P1)(n-1)/n)-1 / (n-1) / n與hw/P11/2 相對。前面的減少壓差和減少流量做為公因數(T, Z, 和 SG)在壓差和流量計算方程式里被刪除。X and Y values are expressed as 0 to 100 percent.X和Y值表示成百分之0到100。The polytropic exponent (n-1) / n equals (log (T2 / T1) / log (P2 / P1).多變指數(n-1) / n等于(log (T2 / T1) / log (P2 / P1)。T1 and T2 are suction and discharge temperatures.T1和T2是入口和出口溫度。P1 and P2 are suction and discharge pressures.P1和P2是入口和出口壓力。SG is gas specific gravity.SG是氣體比重。Z is gas compressibility.Z是氣體可壓縮性。Flow differential pressure (DP) in inches of water is expressed as hw.水流量壓差（DP）微動用hw表示。The surge limit model is a third-order polynomial of the form:喘振限制模型是一個三次多項式形式：X = AY3 + BY2 + CY + DNOTE注意The foregoing equation is written unconventionally to show that the independent variable in the calculation is reduced head, or the Y axis value. The dependent variable is reduced flow, or the X axis value. Reduced head is input, and reduced flow is calculated.上面寫出的方程式不依慣例，顯示計算中的自變量是減少壓差或Y軸值。因變量是減少流量，或X軸值。減少壓差是輸入，減少流量是計算出的。From the operating point Y value (reduced head), the X value (reduced flow), at surge (Xs), can be calculated using the polynomial. Then Xs is multiplied by the sum of one (1) plus the desired protection margin (typically 10 percent) to get the control point Xc. Then Xc (control) is subtracted from X (operating) to find the error.從運行點Y值(減少壓差)，X值（減少流量），喘振(Xs)，利用多項式可以計算出來。Xs被乘上1加預期保護極限（一般為10%）的和便得到控制點Xc。這時Xc（控制）被從X（運行）里減去來發現錯誤。P+I ALGORITHM P+I算法The Solar antisurge controller combines proportional plus integral control modes. The controller function used in the Solar antisurge control loop is:索拉反喘振控制器是比例加積分控制模式。在索拉反喘振控制回路中的控制器函數是：Proportional Term = OP + KP(E0-E1) 比例項 = OP + KP(E0-E1)Integral Term = 0.5(KI)(T)(E0+E1) 積分項 = 0.5(KI)(T)(E0+E1)Derivative Term = (KD)(E0-2E1+E2)/(T) 微分項 = (KD)(E0-2E1+E2)/(T)Then,于是Output = P+I+D 輸出 = P+I+DWhere:這里：OP = Output輸出KP = Proportional Gain比例增益KI = Integral Gain積分增益KD = Derivative Gain微分增益E0 = Current Error電流錯誤E1 = Immediately past Error立即通過錯誤E2 = Error before E1 E1前的錯誤The control algorithm is described in the following figures.控制算法在下圖中有描述Figure 11.2.1 depicts the top control function which takes output from each of the following subroutines, and which dispatches control commands.圖11.2.1描述了頂部控制功能，從下面每個子程序獲得輸出，分派控制命令。Figure 11.2.1 Head versus Flow Antisurge Control Flow Diagram圖11.2.1與流量相對的壓差反喘振控制流程圖View graphic 1圖1View graphic 2圖2View graphic 3圖3Figure 11.2.2 is the filter subroutine to the programmable logic controller (PLC) where process variables are filtered to remove excessive signal noise. From a process variable, FLTR_PV, the last filtered process variable, FLTR_PVF, and the filter constant, FLTR_KF, a new filtered process variable, FLTR_PVF, is generated based on a filter gain FLTR_KF. Maximum and minimum values for the process variable are also generated. The filter constant must be between 0 and +1, or the unfiltered value is returned, indicating the signal was not excessively noisy.圖11.2.2是可編程邏輯控制器(PLC)的過濾器子程序，工藝參數被過濾除去額外的信號噪音。從工藝參數FLTR_PV，最后過濾的工藝參數FLTR_PVF，和過濾器常量FLTR_KF，新過濾的工藝參數FLTR_PVF，基于過濾器增益FLTR_KF產生。同樣產生工藝參數的最大和最小值。過濾器常量必須在0到+1間，否則沒有過濾的值將返回，說明信號不是非常地吵雜。Figure 11.2.2 Filter Diagram圖11.2.2過濾器圖View graphic看圖In the antisurge control logic diagram Figure 11.2.3, X values, ASC_XAXIS, and Y values, ASC_YAXIS, are calculated using the input parameters suction pressure, ASC_SUCPRS, discharge pressure, ASC_DISPRS, suction temperature, ASC_SUCTMP, discharge temperature ASC_DISTMP, and differential pressure across the flow meter, ASC_FLOWDP. Pressures are in psi, temperatures are in degrees F, and flow meter differential pressure is in inches of water. Global parameters, that is, values which are used in the calculation, but not returned as output are polytropic exponent, ASC_PLYEXP, pressure ratio, ASC_PR, and temperature ratio, ASC_TR. The polytropic exponent is a function of gas properties and the efficiency of the compression process. It is the exponent that directly relates the actual temperature rise to the pressure rise.反喘振控制邏輯圖11.2.3，X值ASC_XAXIS，和Y值ASC_YAXIS，利用輸入參數入口壓力ASC_SUCTMP,出口壓力ASC_DISPRS,入口溫度ASC_SUCTMP，出口溫度ASC_DISTMP,和流過流量計的壓差ASC_FLOWDP可以計算出來。壓力單位psi，溫度單位是F，流量計壓差是水的英寸數。全局參數在計算中使用，但作為輸出返回，是多變指數ASC_PLYEX，壓力比率ASC_PR,和溫度比率ASC_TR。多變指數是氣體道具和壓縮機處理效率的一個函數。它是直接聯系實際溫度上升和壓力上升的指數。Figure 11.2.3 Antisurge System Control Logic Diagram圖11.2.3反喘振系統控制邏輯圖View graphic圖In the polynomial equation subroutine (Figure 11.2.4), surge margins are determined by analysis of the X and Y values generated by the routine depicted in Figure 11.2.4. A Y value, POLYEQNY, is calculated using the input variable X, POLYEQNX, and the input coefficients POLYEQNA, POLYEQNB, POLYEQNC, and POLYEQND. The constant factors POLYFCTA, POLYFCTB, and POLYFCTC are used in the calculation but are not returned as output. The result is limited by POLYMAX and POLYMIN, values which approximately define the upper 50 percent of the compressors operating speed.多項式方程子程序里（圖11.2.4），喘振極限由分析圖11.2.4里描述的程序產生的X和Y值決定。Y值POLYEQNY是利用輸入變量X POLYEQNX和輸入系數POLYEQNA, POLYEQNB, POLYEQNC, 和 POLYEQND計算出來的。常因子POLYFCTA, POLYFCTB, 和 POLYFCTC在計算中使用但不作為輸出返回。結果受POLYMAX 和 POLYMIN的限制，值大約是壓縮機運行速度的50%以上。Figure 11.2.4 Polynomial Equation Diagram圖11.2.4多項式方程圖View graphic圖The controller function in the PLC acts to reduce the process error by opening the recycle control valve. PLC里的控制器函數通過打開再循環控制閥減少過程錯誤。The routine depicted in Figure 11.2.5, similar to the preceding figure, calculates errors and returns them without modification.圖11.2.5里描述的程序同前面的圖相似，計算錯誤并沒有修改就返回。Figure 11.2.5 Error Flow Diagram圖11.2.5錯誤流程圖View graphic圖The routine depicted in Figure 11.2.6 selects gains based on the operating position relative to the control line. The gains move the recycle control valve. High gains are output when the compressor has a insufficient surge margin, in which case, the operating point is shown on the surge display X:Y plot to the left of the desired range, and the recycle valve is opened. Low gains are output when the compressor has a large surge margin, in which case, the operating point is shown on the surge display X:Y plot to the right of the desired range, and the recycle valve is closed. Inputs are the previous output, PID_OP, and proportional, integral, and derivative gains, PID_KP, PID_KI, and PID_KD. Errors, PID_E0, PID_E1, PID_E2, are also input. A new gain output, PID_OP, between 0 and 100, is output.圖11.2.6里描述的程序選擇基于相對于控制線的運行位置的增益。這些增益移動再循環控制閥。當壓縮機喘振極限不足時輸出高增益，這種情況下，運行點在預置范圍的左邊喘振顯示X：Y區域出現，并且再循環閥打開。當壓縮機喘振極限足夠時輸出低增益，這種情況下，運行點在預置范圍的右邊喘振顯示X：Y區域出現，并且再循環閥關閉。輸入優先于輸出PID_OP，比例，積分和微分增益PID_KP, PID_KI, 和 PID_KD。錯誤PID_E0, PID_E1, PID_E2也是輸入。在0到100之間的一個新增益輸出PID_OP，是輸出。Figure 11.2.6 PID Controller Flow Diagram圖11.2.6PID控制器流程圖View graphic圖CONSTANTS常數Table 11.2.1 describes operator-set constant values, Kvals, which are used in the programmable logic controller (PLC) algorithm.表11.2.1描述了操作員設置常量值Kvals,在可編程邏輯控制器(PLC)運算中使用。Table 11.2.1 Operator-Set Constant Values, Kvals表11.2.1操作員設定常量值KvalsSymbol符號Description描述HPC KPFASTProportional gain limit比例增益極限HPC KIFASTIntegral gain limit積分增益極限HPC KPSLOWProportional gain limit比例增益極限HPC KISLOWIntegral gain limit積分增益極限Table 11.2.2 describes programmed constant values, Kvals, which are used in the PLC.表11.2.2描述了在PLC中使用的編程常量值Kvals。Table 11.2.2 Programmed Constant Values, Kvals編程常量值KvalsSymbol符號Description描述HPC KCLFCTSurge margin喘振極限HPC KDBFCTDeadband width死區寬度HPC SCVOPNManual opening rate手動打開比率HPC SCVCLSManual closing rate手動關閉比率HPC QXMTRFlow transmitter range流量變送器范圍HPCSUCPXMTSuction pressure transmitter range入口壓力變送器范圍HPCDISPXMTDischarge pressure transmitter range出口壓力變送器范圍NGPLOADSPNgp load speed NGP負荷速度HPCASC_ACoefficient, 3rd order polynomial三次多項式系數HPCASC_BCoefficient, 3rd order polynomial三次多項式系數HPCASC _CCoefficient, 3rd order polynomial三次多項式系數HPCASC _DCoefficient, 3rd order polynomial三次多項式系數HPCASCXMAXEquation range limit方程范圍限制HPCASCYMINEquation range limit方程范圍限制HPCASCYMAXEquation range limit方程范圍限制LPCASC_KFFilter constant過濾器常數SURGE DETECTOR喘振探測器The surge detector operates as part of the antisurge system. The differential pressure across the flow orifice is used to compute the rate-of-decrease of flow through the compressor and is compared to a preset value. If the maximum value exceeds the minimum value by a preset amount (typically 25 percent), one pulse is counted, and the recycle valve is opened 20 percent. If five pulses occur within ten seconds, the engine is shut down and a message indicating that the compressor is in surge appears on the display terminal.喘振探測器是反喘振系統的一部分。通過流量孔的壓差用來計算流過壓縮機的流量的減少比率，并與預置值進行比較。如果最大值超過最小值的百分數（一般為25%），計算為一個脈沖，再循環閥打開20%。如果十秒內產生五個脈沖，引擎將關閉并在終端顯示器上出現壓縮機在喘振的信息。For single pulses or less than five pulses in a ten-second period, the recycle valve closes comparatively slowly. Closure from fully open requires about a minute, while opening requires milliseconds.因為單個或十秒內少于五個脈沖，再循環閥關閉相當慢。從全開到關閉大概需要一分鐘，打開需要幾毫秒。SYSTEM OPERATION系統運行The antisurge control loop is disabled until engine speed is greater than a preset value. Below this value, the recycle control valve is fully open to allow maximum gas flow through the compressor.反喘振控制回路直到引擎速度高于預置值時才起作用。在這個值下時，再循環控制閥全開來讓做大氣體量流入壓縮機。Above loading speed, the antisurge control system is enabled and the recycle valve can be closed. Pressures and temperatures in the suction and discharge lines are measured and head across the compressor is calculated. Flow through the compressor is determined by measuring pressure drop across an orifice in the suction line, discharge line, or compressor impeller eye. Signals from these transmitters are processed by the control system. If the surge margin falls below a preset value, the signal to the recycle valve is reduced. The recycle valve opens a fraction proportional to the signal value. With the valve opened, a portion of the gas from the discharge side of the compressor is routed back to the suction side, and flow through the compressor increases. When the condition that caused the antisurge action disappears, the recycle control valve closes and the compressor resumes normal operation.負荷速度之上，反喘振控制系統起作用并能關閉再循環閥。測量入口和出口管線的壓力和溫度，計算流過壓縮機的壓差。通過壓縮機的流量由測量通過入口管線、出口管線或壓縮機葉輪入口孔板的壓力決定。從這些變送器來的信號被控制系統處理。如果喘振極限降到預置值以下，去再循環閥的信號減少。再循環閥按信號值比例打開一點點。隨著閥的打開，壓縮機出口側的一部分氣體返回到入口側，壓縮機的流量增加。當導致反喘振動作的條件消失，再循環閥關閉并且壓縮機恢復正常運行。DISPLAY顯示This section describes the techniques typically used to construct the antisurge control display screen.本節描述了用于建立反喘振控制顯示屏的一般技術。On the left of the screen, operating mode, operating conditions, setpoint, valve position and engine speed are displayed.屏幕左邊顯示有運行模式，運行狀態，設定點，閥的位置和引擎速度。On the right of the screen is an X:Y plot showing surge limits and operating point. For display, X and Y values are converted to percentages. A white cross defining a point, X, Y, shows the operating point. Plus and minus one (1) are added to the operating point Y, providing Y and Y. X and X are then calculated using the polynomial equation providing Y and Y. X Y and X, Yare two points at the surge limit.屏幕右邊是一個顯示喘振極限和運行點的X:Y區域。為了顯示，X和Y值被轉換成百分數。一個白十字定義一個點，X，Y，顯示運行點。運行點Y加上正負1，得到Y和 Y。利用Y和 Y多項式方程計算出X和 X。X Y 和 X, Y是喘振極限上的兩個點。The displayed surge limit takes the form:顯示的喘振極限變成下面形式：Y = MX + BWhere這里(X - X)/(Y - Y) = MB = Y - MXM = KSL = slope of the surge line喘振線的斜率B = SLB = Y intercept for KSL, KCL, AND KDBThe following three lines are displayed on the screen:下面三條線在屏幕上顯示：KSL = slope of surge limit, SURGE LINE,喘振極限的斜率，喘振線，KCL = slope of the control line, CONTROL LINE,控制線的斜率，控制線，KDB = slope of the deadband line, DEADBAND LINE,死區線的斜率，死區線，Where這里KCL = KSL times 1 plus desired protection margin KSL時間1加期望保護的極限KDB = KCL times 1 plus desired deadband width KCL時間1加期望的死區寬度Figure 11.2.7 graphically describes the development of these control lines.圖11.2.7繪出了這些控制線的走向Figure 11.2.7 Display Screen Development圖11.2.7顯示屏走向View graphic圖Antisurge control screens are shown in Figures 11.2.8 and 11.2.9.反喘振空子屏在圖11.2.8和11.2.9顯示。Figure 11.2.8 Antisurge Control Screen圖11.2.8反喘振控制屏View graphic圖Figure 11.2.9 Antisurge Control Screen圖11.2.9反喘振控制屏View graphic圖Figure 11.2.10 is a flow diagram for an algorithm that develops the antisurge control screen.圖11.2.10是反喘振控制屏走向的計算流程圖Figure 11.2.10 Antisurge Control Screen Algorithm反喘振控制屏計算View graphic圖11.2.2 Process Control System過程控制系統During operation, the process control system continually monitors and controls turbine engine/compressor speed.運行期間，過程控制系統不斷監視和控制透平引擎/壓縮機速度。Typical process control screens are shown in Figure 11.2.11 and 11.2.12.典型的過程控制屏在圖11.2.11和11.2.12里顯示。Figure 11.2.11 Digital Display Process Control Screen圖11.2.11數字顯示過程控制屏View graphic圖Figure 11.2.12 Process Control Screen圖11.2.12過程控制屏View graphic圖When the control system is in the LOCAL mode, the increase (INC) and decrease (DEC) pushbuttons on the turbine control panel are active for the selected setpoint: NGP, DIS PRS (discharge pressure), SUC PRS (suction pressure), or FLOW. The selected setpoint is highlighted, and blue up and down triangles appear next to the local setpoint value to indicate the setpoint the pushbuttons are controlling.當控制系統在LOCAL（就地）模式，透平控制面板上的增加（INC）和減少（DEC）按鈕能調整選擇的設定點：NPG，DIS PRS（出口壓力），SUC PRS（入口壓力），或FLOW。被選擇的設定點突出來，藍色上和下三角形出現在本地設定值顯示設定點按鈕在控制中。When the control system is in the REM (Remote) mode, the setpoint is controlled by an external source.當控制系統在REM（遙控）模式，設定點由外部源控制。When the load setpoint is in MAN (Manual), the unit NGP setpoint is controlled by a local or remote setpoint. When the load setpoint is in AUT (Auto) mode, the unit setpoint is controlled by process control or load share control setpoints. To select the control mode, press the MAN/AUTO Switch on the turbine control panel, or, on the PROCESS CONTROL screen, use the keyboard up, down, left, right arrows to position the asterisk on the LOAD SET POINT MODE selection and press CNTRL/ENTER to toggle between MAN and AUT. When the LOAD SET POINT MODE selection is in MAN, the OFF/ON asterisk label changes from LOAD SHARE MODE to NGP MSTR (master) MODE.當負載設定點是MAN（手動），NGP設定點受本地或遙控設定點控制。當負載設定點在AUT（自動）模式，設定點受過程控制或負載共享控制設定點控制。按透平控制面板上的MAN/AUTO開關或在壓力控制屏上用鍵盤上，下，左，右箭頭讓星號位于LOAD SET POINT MODE選擇處并按CNTRL/ENTER鍵選定MAN或AUT。當LOAD SET POINT MODE 選擇是MAN，OFF/ON星號標簽由LOAD SHARE MODE 改變到NGP MSTR MODE。MULTIPLE PROCESS CONTROL多過程控制With multiple process control, the lower error_gain value is chosen (minimum speed setpoint) by the system (MIN GATE). The selected error_gain parameter goes to the integrator which brings the error to zero by changing the actual gas producer speed setpoint. See Figure 11.2.13.使用多過程控制，低級錯誤增益值被系統（MIN GATE）選定（最小速度設定點）。被選擇的錯誤增益參數進入積分器，積分器通過改變實際壓氣機速度設定點來將錯誤變成零。If the compressor operating point is in or to the left of the antisurge control deadband, the gas producer rate of change is reduced (typically, to 0.1%/second).如果壓縮機運行點在反喘振控制死區里面或左邊，壓氣機速度改變減小（一般，到0.1%/秒）。Figure 11.2.13 Multiple Pr