WO2001016523A1 - Adaptive predictive control of pressure in a natural gas distribution system - Google Patents

Adaptive predictive control of pressure in a natural gas distribution system Download PDF

Info

Publication number
WO2001016523A1
WO2001016523A1 PCT/US2000/023485 US0023485W WO0116523A1 WO 2001016523 A1 WO2001016523 A1 WO 2001016523A1 US 0023485 W US0023485 W US 0023485W WO 0116523 A1 WO0116523 A1 WO 0116523A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
controller
low
adaptive
setpoint
Prior art date
Application number
PCT/US2000/023485
Other languages
French (fr)
Inventor
Joe W. Mccarty
Mark Douglas Whinery
Mary Barbara Abens
Original Assignee
Fisher Controls International, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fisher Controls International, Inc. filed Critical Fisher Controls International, Inc.
Priority to AU70780/00A priority Critical patent/AU7078000A/en
Publication of WO2001016523A1 publication Critical patent/WO2001016523A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17D—PIPE-LINE SYSTEMS; PIPE-LINES
    • F17D1/00—Pipe-line systems
    • F17D1/02—Pipe-line systems for gases or vapours
    • F17D1/04—Pipe-line systems for gases or vapours for distribution of gas
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B13/00—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion
    • G05B13/02—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric
    • G05B13/04—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric involving the use of models or simulators
    • G05B13/048—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric involving the use of models or simulators using a predictor

Definitions

  • This invention relates to apparatus and a method for controlling pressure in a gas distribution system, and in particular to the adaptive predictive control of such pressure in response to the low-pressure point of the system.
  • the adaptive pressure control system of the present invention was developed to control and manage pressure in natural gas distribution systems. As shown in Figure 1, the adaptive pressure control system consists of two main components or subsystems:
  • the Pressure Control System is located entirely in the field and is responsible for controlling pressure on a localized basis.
  • the Pressure Management System consists of a dedicated personal computer and software that communicates with the Pressure Control System. It provides a pressure information database as well as an operator interface to the field system.
  • FIG. 2 shows the District Regulator
  • FIG. 1 shows the Low-Pressure Point Controller (DRC)
  • Figure 3 shows the Low-Pressure Point Controller (LPPC) .
  • the PPC is located at the low- pressure point (LPP) in the gas distribution system and is responsible for maintaining the low-pressure point at a user-defined setpoint.
  • the LPPC can communicate with up to five DRCs, as shown in Figure 4.
  • the district regulator maintains a constant pressure at the station outlet, and control is implemented independent of the pressure at the low- pressure point (LPP) .
  • the setpoint at the LPP is based on system requirements during peak load and, therefore, in order to maintain the LPP above a minimum safe pressure, the district regulator local setpoint (LSP) must be set much higher than is actually needed most of the time during a typical day.
  • Figure 6 shows a closed loop with an "ideal" pressure controller closing the loop.
  • the setpoint at the LPP is achieved by constantly varying the setpoint of the district regulator, which is the opposite of what happens in previously known control systems .
  • FIG. 7 shows how the adaptive pressure control system 20 of the present invention provides "ideal" control of the LPP, using closed-loop setpoint control.
  • the adaptive pressure control system 20 includes an Adaptive Predictive Controller (APC) 22 and a Low-Pressure Point Controller (LPPC) 24.
  • the district regulator (DR) 26 still has a local mechanical setpoint (LSP) that is set to some minimum setting in case of electronic controller failure.
  • LSP local mechanical setpoint
  • the remote setpoint (RSP) is set from the Pressure Management System and is used during override and in setting initial conditions.
  • the pressure setpoint (SP) is set at the LPPC to the desired minimum pressure.
  • a deadband is also set by the operator around the setpoint. If the pressure wanders outside the deadband, then the adaptive predictive controller 22 algorithm drives the process back to the setpoint.
  • the purpose of the adaptive pressure control system 20 is to control the pressure at the LPP 28 to a user-defined setpoint.
  • the LPPC calculates an average of the pressure over a minute and then checks the average against the user-defined setpoint.
  • LPPC Average Pressure
  • SP lppc Setpoint for LPPC.
  • R t .- L Rate of change of error at time t-1.
  • SP IL New Inner Loop setpoint
  • S i Lo i Current Inner Loop setpoint
  • T0D m Time-of-Day value for current minute of day
  • a n Adaptive value for current minute of day.
  • the Time-of-Day value for the current minute of the day is calculated based upon the received change in Inner Loop setpoint ( ⁇ IL ⁇ minute of the day.
  • a Time-of-Day profile (see Figure 9) stores 1440 values that represent each minute of the day and how each minute of the day affects the LPP in the system.
  • the Time-of-Day profile is being built, the current minute of the day and the 15 minutes leading up to the current minute have their Time-of-Day values changed depending upon the mode of the system.
  • To build the Time-of-Day profile the following calculation is used if the system is in Adaptive mode:
  • T0D x T0D xold + ( K ⁇ 0D * ⁇ IL ⁇ ⁇
  • T0D x New Time-of-Day value for current minute of day + previous 15 minutes
  • T0D xold Existing Time-of-Day value for current minute of day + previous 15 minutes
  • the Time-of-Day profile is decayed to move the setpoint or output away from its limits .
  • the following calculation is used:
  • TOD x New Time-of-Day value for current minute of day + previous 15 minutes
  • TOD xold Existing Time-of-Day value for current minute of day + previous 15 minutes
  • the adaptive value for the current minute of the day (A is calculated based upon the change in temperature and the coefficient of temperature (see Figure 9) . It will only be calculated if the Inner Loop setpoint and the temperature have changed over the last minute. To calculate the Adaptive value for the current minute of the day, the following calculation is used:
  • A.- Adaptive value for current minute of day
  • CT Current Coefficient of Temperature
  • TMP m Temperature at current minute of day
  • TM p m oi d Temperature from previous minute of day.
  • the adaptive error is calculated to ensure that A,- is not too large. The following calculation is used to discover the adaptive error:
  • SPi mo i a Inner Loop setpoint from previous minute of day
  • A__ Adaptive value for current minute of day.
  • E a is too large or too small, then A., is set to zero (0) and the coefficient of temperature is not recalculated. But, if E a is within range, then A-, is found to be acceptable and E a is used to recalculate the coefficient of temperature if the minimum or maximum Inner Loop setpoint or output has not been reached. To recalculate the coefficient of temperature, the following calculation is used:
  • CT CT old + (K a * E a * (TMP m - TMP mold ) ) ( 8 )
  • CT New Coefficient of Temperature
  • CT old Current Coefficient of Temperature
  • K a Adaptive gain
  • E a Adaptive error
  • TMP m Temperature at current minute of day
  • SPi Lo i a Current Inner Loop setpoint, and IL received from LPP.
  • Time-of-Day value and the Adaptive value for the current minute of the day are not used to change the Inner Loop setpoint when the system is in Outer Loop mode. They are, however, calculated to allow for the Time-of-Day profile and the coefficient of temperature to be built and calculated respectively.
  • the Adaptive value (A , adaptive error (E a ) , and the coefficient of temperature (CT) are calculated the same way in Outer Loop mode as in Adaptive mode.
  • the Time-of- Day profile is calculated differently. To build the Time-of-Day profile in Outer Loop mode, the following calculation is used:
  • TOD x (TOD xold * ( 1 - 1/BP) ) + ( ⁇ IL ⁇ ⁇
  • TOD x New Time-of-Day value for current minute of day + previous 15 minutes
  • T0D xold Current Time-of-Day value for current minute of day + previous 15 minutes
  • the DRC calculates the new Inner Loop setpoint (SP IL ) , it is checked against an Inner Loop setpoint minimum and maximum to ensure that the district regulator is not getting out of control.
  • the Inner Loop ( Figure 11) of the DRC uses the following algorithm to create the PID control functionality :

Abstract

A gas distribution system to control and manage pressure to users on a pipeline to maintain the low-pressure point at a defined setpoint. A pressure regulator (26) upstream of users regulate the pressure supplied to the users coupled to the pipeline. An adaptive pressure controller (20) with a low-pressure controller (24) m onitors the low-pressure point (PTL) and controls the pressure regulator setpoint (SV) to maintain the low-pressure point pressure value (PTL) to be greater than a predetermined low-pressure value. An adaptive predictive controller (22) is responsive to the time of day and temperature to correspondingly control the pressure regulator (26).

Description

ADAPTIVE PREDICTIVE CONTROL OF PRESSURE IN A NATURAL GAS DISTRIBUTION SYSTEM
This application claims the benefit of U.S. provisional patent application Serial No. 60/151,186, filed August 27, 1999.
This invention relates to apparatus and a method for controlling pressure in a gas distribution system, and in particular to the adaptive predictive control of such pressure in response to the low-pressure point of the system.
The adaptive pressure control system of the present invention was developed to control and manage pressure in natural gas distribution systems. As shown in Figure 1, the adaptive pressure control system consists of two main components or subsystems:
1) The Pressure Control System. 2) The Pressure Management System.
The Pressure Control System is located entirely in the field and is responsible for controlling pressure on a localized basis. The Pressure Management System consists of a dedicated personal computer and software that communicates with the Pressure Control System. It provides a pressure information database as well as an operator interface to the field system.
Figure 2 shows the District Regulator
Controller (DRC) , and Figure 3 shows the Low-Pressure Point Controller (LPPC) . The PPC is located at the low- pressure point (LPP) in the gas distribution system and is responsible for maintaining the low-pressure point at a user-defined setpoint. The LPPC can communicate with up to five DRCs, as shown in Figure 4.
As depicted in Figure 5, in previous gas control systems, the district regulator maintains a constant pressure at the station outlet, and control is implemented independent of the pressure at the low- pressure point (LPP) . The setpoint at the LPP is based on system requirements during peak load and, therefore, in order to maintain the LPP above a minimum safe pressure, the district regulator local setpoint (LSP) must be set much higher than is actually needed most of the time during a typical day. Some systems allow the operator to remotely change the district regulator setpoint, but even this type of control is not based on the pressure at the LPP.
In contrast with such previously known systems,
Figure 6 shows a closed loop with an "ideal" pressure controller closing the loop. The setpoint at the LPP is achieved by constantly varying the setpoint of the district regulator, which is the opposite of what happens in previously known control systems .
Figure 7 shows how the adaptive pressure control system 20 of the present invention provides "ideal" control of the LPP, using closed-loop setpoint control. The adaptive pressure control system 20 includes an Adaptive Predictive Controller (APC) 22 and a Low-Pressure Point Controller (LPPC) 24. The district regulator (DR) 26 still has a local mechanical setpoint (LSP) that is set to some minimum setting in case of electronic controller failure. The remote setpoint (RSP) is set from the Pressure Management System and is used during override and in setting initial conditions. The pressure setpoint (SP) is set at the LPPC to the desired minimum pressure. A deadband is also set by the operator around the setpoint. If the pressure wanders outside the deadband, then the adaptive predictive controller 22 algorithm drives the process back to the setpoint.
The purpose of the adaptive pressure control system 20 is to control the pressure at the LPP 28 to a user-defined setpoint. The LPPC calculates an average of the pressure over a minute and then checks the average against the user-defined setpoint.
et = PV: lppc Sp lppc ( 1 )
where : et = Error at time t,
PVippc = Process Variable for
LPPC = Average Pressure, and SPlppc = Setpoint for LPPC.
If et is less than the error deadband, ed, then the pressure at the LPP is acceptable and nothing further will happen. However, if et is greater than ed, then the LPPC will calculate a change to the Inner Loop setpoint for each DRC. Because each DRC can have different gains and affect the system differently, the change in Inner Loop setpoint calculated by the LPPC is specific to each DRC. To calculate the change in Inner Loop setpoint, the following calculation is used:
Δ IL p s Δ j. tΔ DΔ Δ
where : IL KP = Proportional gain,
Fs = Scale Factor,
Δ et = Error at time t, et-1 = Error at time t-1, Kτ = Integral gain (repeats/minute) ,
Δ
Δ
Δ
Rt = Rate of change of error at time t = (et-et-1) /Δ
Rt.-L = Rate of change of error at time t-1.
After the LPPC has calculated the change in Inner Loop setpoint (Δ ILΔ that DRC.
If the system is in Adaptive mode (see Figure 8) , then the DRC will change its Inner Loop setpoint every minute based upon the following calculation:
Figure imgf000006_0001
where :
SPIL = New Inner Loop setpoint, S iLoi = Current Inner Loop setpoint, Δ IL received from LPPC,
T0Dm = Time-of-Day value for current minute of day, and An = Adaptive value for current minute of day.
The Time-of-Day value for the current minute of the day (TOD is calculated based upon the received change in Inner Loop setpoint (Δ ILΔ minute of the day. A Time-of-Day profile (see Figure 9) stores 1440 values that represent each minute of the day and how each minute of the day affects the LPP in the system. When the Time-of-Day profile is being built, the current minute of the day and the 15 minutes leading up to the current minute have their Time-of-Day values changed depending upon the mode of the system. To build the Time-of-Day profile, the following calculation is used if the system is in Adaptive mode:
T0Dx = T0Dxold + ( Kτ0D * Δ ILΔ Δ
where :
T0Dx = New Time-of-Day value for current minute of day + previous 15 minutes, T0Dxold = Existing Time-of-Day value for current minute of day + previous 15 minutes, KT0D = Time-of-Day profile gain (1% = 0.01), and
Δ ττ. received from LPP.
However, if the DRC is against the minimum or maximum Inner Loop setpoint or output while in Adaptive mode, the Time-of-Day profile is decayed to move the setpoint or output away from its limits . To decay the Time-of-Day profile, the following calculation is used:
TOD„ TOD„ * Dτ (5)
where :
TODx = New Time-of-Day value for current minute of day + previous 15 minutes, TODxold = Existing Time-of-Day value for current minute of day + previous 15 minutes, and
DT0D = Time-of-Day profile decay (99% = 0.99)
The adaptive value for the current minute of the day (A is calculated based upon the change in temperature and the coefficient of temperature (see Figure 9) . It will only be calculated if the Inner Loop setpoint and the temperature have changed over the last minute. To calculate the Adaptive value for the current minute of the day, the following calculation is used:
, = CT * (TMPm - TMPmold) (6)
where : A.- = Adaptive value for current minute of day,
CT = Current Coefficient of Temperature, TMPm = Temperature at current minute of day, and ™p moid = Temperature from previous minute of day.
After calculating A,., the adaptive error is calculated to ensure that A,- is not too large. The following calculation is used to discover the adaptive error:
Ea = ( SPILm - SPILmold) - A,. ( 7 )
where :
Ea = Adaptive error,
SPim = Inner Loop setpoint at current minute of day,
SPimoia = Inner Loop setpoint from previous minute of day, and A__ = Adaptive value for current minute of day.
If Ea is too large or too small, then A., is set to zero (0) and the coefficient of temperature is not recalculated. But, if Ea is within range, then A-, is found to be acceptable and Ea is used to recalculate the coefficient of temperature if the minimum or maximum Inner Loop setpoint or output has not been reached. To recalculate the coefficient of temperature, the following calculation is used:
CT = CTold + (Ka * Ea * (TMPm - TMPmold) ) ( 8 )
where : CT = New Coefficient of Temperature, CTold = Current Coefficient of Temperature, Ka = Adaptive gain, Ea = Adaptive error, TMPm = Temperature at current minute of day, and
TMl?moid = Temperature from previous minute of day.
If the system is in Outer Loop mode (Figure 10) , then the DRC will change its Inner Loop setpoint every minute based upon the following calculation:
SPII SPnoid + Δ
where :
SPIL = New Inner Loop setpoint,
SPiLoia = Current Inner Loop setpoint, and IL received from LPP.
Notice that the Time-of-Day value and the Adaptive value for the current minute of the day are not used to change the Inner Loop setpoint when the system is in Outer Loop mode. They are, however, calculated to allow for the Time-of-Day profile and the coefficient of temperature to be built and calculated respectively. The Adaptive value (A , adaptive error (Ea) , and the coefficient of temperature (CT) are calculated the same way in Outer Loop mode as in Adaptive mode. The Time-of- Day profile, however, is calculated differently. To build the Time-of-Day profile in Outer Loop mode, the following calculation is used:
TODx = (TODxold * ( 1 - 1/BP) ) + (Δ IL Δ Δ
where :
TODx = New Time-of-Day value for current minute of day + previous 15 minutes, T0Dxold = Current Time-of-Day value for current minute of day + previous 15 minutes, BP = Back Propagation into profile in minutes of day = 15, and IL
From LPP.
After the DRC calculates the new Inner Loop setpoint (SPIL) , it is checked against an Inner Loop setpoint minimum and maximum to ensure that the district regulator is not getting out of control. To control the District Regulator, the Inner Loop (Figure 11) of the DRC uses the following algorithm to create the PID control functionality :
If et is greater than ed , then :
0t - 0t-1 = KPFS (Δ . tΔ DΔ Δ
If et is less than or equal to ed , then :
ot - Ot-1 = 0 . 0 where :
Ot - 0,..! = Change in output to be added to the actual output, 0t = Output at time t (%) , 0t-1 = Output at time t-1 (%) , KP = Proportional gain, Kτ = Integral gain (repeats/minute) , KD = Derivative gain (minute) , Rt = Rate of change of error at time t = (et - et-1)/Δ Rt-1 = Rate of change of error at time t-1, et = Error at time t = PVDR - SPDR, et-1 = Error at time t-1, ed = Error deadband, Δ s
PVDR = Process Variable for
DR = Outlet Pressure, and SPDR = Setpoint for DR.
The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

Claims

IN THE CLAIMS:
1. A gas distribution system distributing gas to users comprising: a pipeline for supplying gas to a plurality of users; a pressure regulator coupled to said pipeline upstream of said users; and an adaptive pressure controller monitoring the gas pressure at a low-pressure point downstream of said users and controlling said pressure regulator to enable the gas pressure downstream of said users at said low- pressure point to be greater than a predetermined low- pressure value.
2. A gas distribution system according to claim 1, wherein said pressure regulator includes a set point, and said adaptive pressure controller changes said pressure regulator setpoint.
3. A gas distribution system according to claim 2, wherein said adaptive pressure controller includes a low-pressure point controller having a controller setpoint input, said low-pressure point controller monitoring said gas pressure at said low- pressure point and comparing said monitored low-pressure point gas pressure with said controller setpoint input to provide a low-pressure point controller output for changing said pressure regulator setpoint .
4. A gas distribution system according to claim 3, including a plurality of said pipelines, each including a respective pressure regulator coupled to said low-pressure point controller, wherein said low-pressure point controller selectively changes the pressure regulator setpoint of each respective pressure regulator in response to the monitored low-pressure point of the gas pressure downstream of said users in said plurality of pipelines.
5. A gas distribution system according to claim 1, wherein said adaptive pressure controller includes an adaptive predictive controller responsive to the time of 'day and temperature and providing an adaptive predictive controller output for correspondingly controlling said pressure regulator.
6. A gas distribution system according to claim 5, wherein said pressure regulator includes a set point, and said adaptive predictive controller changes said pressure regulator setpoint.
7. A gas distribution system according to claim 3, wherein said adaptive pressure controller includes an adaptive predictive controller responsive to the time of day and temperature and providing an adaptive predictive controller output for correspondingly changing said pressure regulator setpoint.
8. A gas distribution system according to claim 7, including combining means for combining said low-pressure point controller output and said adaptive predictive controller output and coupled to said pressure regulator for changing said pressure regulator setpoint.
9. A gas distribution system according to claim 4, including a respective adaptive predictive controller coupled between each of said pressure regulators and said low-pressure point controller, each respective adaptive predictive controller responsive to the time of day and temperature and providing a respective adaptive predictive controller output for correspondingly controlling a respective pressure regulator setpoint.
10. A gas distribution system according to claim 9, including respective combining means for combining said low- pressure point controller output and a respective adaptive predictive controller output and coupled to a respective pressure regulator for corresponding controlling said pressure regulator setpoint .
PCT/US2000/023485 1999-08-27 2000-08-25 Adaptive predictive control of pressure in a natural gas distribution system WO2001016523A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU70780/00A AU7078000A (en) 1999-08-27 2000-08-25 Adaptive predictive control of pressure in a natural gas distribution system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US15118699P 1999-08-27 1999-08-27
US60/151,186 1999-08-27

Publications (1)

Publication Number Publication Date
WO2001016523A1 true WO2001016523A1 (en) 2001-03-08

Family

ID=22537675

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2000/023485 WO2001016523A1 (en) 1999-08-27 2000-08-25 Adaptive predictive control of pressure in a natural gas distribution system

Country Status (2)

Country Link
AU (1) AU7078000A (en)
WO (1) WO2001016523A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9709998B2 (en) 2013-03-14 2017-07-18 Marshall Excelsior Co. Pressure regulator

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0087766A1 (en) * 1982-02-25 1983-09-07 ESG Elektronik-System- Gesellschaft mbH Process to control a gas network, especially under high pressure
US5047965A (en) * 1989-01-05 1991-09-10 Zlokovitz Robert J Microprocessor controlled gas pressure regulator
DE4205010A1 (en) * 1992-02-19 1993-08-26 Hansjuergen Dr Ing Richter Gas distribution system for mixture of consumers - has storage capacity of gas ring set by computed demand w.r.t. varying conditions and by selection of pipe diameter.
WO1999040360A1 (en) * 1998-02-04 1999-08-12 Gas Research Institute Adaptive system for predictive control of district pressure regulators

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0087766A1 (en) * 1982-02-25 1983-09-07 ESG Elektronik-System- Gesellschaft mbH Process to control a gas network, especially under high pressure
US5047965A (en) * 1989-01-05 1991-09-10 Zlokovitz Robert J Microprocessor controlled gas pressure regulator
DE4205010A1 (en) * 1992-02-19 1993-08-26 Hansjuergen Dr Ing Richter Gas distribution system for mixture of consumers - has storage capacity of gas ring set by computed demand w.r.t. varying conditions and by selection of pipe diameter.
WO1999040360A1 (en) * 1998-02-04 1999-08-12 Gas Research Institute Adaptive system for predictive control of district pressure regulators

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9709998B2 (en) 2013-03-14 2017-07-18 Marshall Excelsior Co. Pressure regulator

Also Published As

Publication number Publication date
AU7078000A (en) 2001-03-26

Similar Documents

Publication Publication Date Title
RU2084704C1 (en) Method for adjustment of compressor station
CN103115243B (en) Control equipment and control method of natural gas pipeline dispatching electric control valve
CA2159790C (en) Control of prime mover in hvac distribution system
KR20010040699A (en) Adaptive system for predictive control of district pressure regulators
RU2689561C2 (en) Method of controlling water tank pumping assembly layout and water reservoir pumping assembly delivery arrangement
EP1000389B1 (en) Adaptive cascade control algorithm
CN102621883B (en) PID (proportion integration differentiation) parameter turning method and PID parameter turning system
WO2001016523A1 (en) Adaptive predictive control of pressure in a natural gas distribution system
JP2985235B2 (en) Flow control method of refining gas in smelting furnace
CA1170778A (en) Method of minimizing the cost of operation of a process
JPH0895645A (en) Water supply terminal pressure controller
JPH07210208A (en) Autotuning method for thermal power plant and thermal power plant controller utilizing the same
CN109791395B (en) Regulation device with adjustability of regulation performance
CN113803121B (en) Automatic control method and system for low-pressure steam turbine and power generation system
US4976108A (en) Turbine efficient valve position computer
CN114935111A (en) Natural valve station heating system and method
JP5313848B2 (en) Water supply pressure control system and method
CN113867134A (en) PID control dead zone adjusting method based on programmable logic controller
JP2001295607A (en) Method and device for controlling load of thermal power plant
JP2001027104A (en) Condensate flow control method for condensate steam turbine
EP3528062A1 (en) Actuator control system with transient reduction after redundancy level changes
JPH01320514A (en) Control method in vapor distribution system
JP7242383B2 (en) CONTROL METHOD OF GAS DIFFERENTIAL PRESSURE GENERATOR, GAS DIFFERENTIAL PRESSURE GENERATOR, AND CONTROL PROGRAM
JP3628884B2 (en) Steam header pressure controller
JP3417766B2 (en) Water supply planning support device and water supply control system

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP