Water turbine speed regulation system and method capable of intelligently regulating parameters

Abstract

The invention discloses a water turbine speed regulation system and method capable of intelligently regulating parameters. The speed regulation system comprises a speed regulator PLC control system and a unit simulation PLC system. In the parameter adjusting process, the speed regulator PLC control system sends water head and opening given signals to the unit simulation PLC system, and the unit simulation PLC system feeds back unit frequency, opening and active power signals to the speed regulator PLC control system; when a parameter adjusting instruction is received or water head change exceeds a set value, a speed regulator PLC control system extracts opening and power step response signals from a simulation system under the current condition, and PID parameters of a speed regulating system are set based on a Lambda setting method by analyzing key indexes of the signals. According to the method, the PID parameters of the speed regulation system can be intelligently and accurately regulated under different water heads, the regulation intelligence and accuracy of the speed regulation system are improved, and a guarantee is provided for safe and stable operation of a power system.

Description

Technical Field

[0001] The invention belongs to the technical field of water turbine speed regulation simulation, and relates to a water turbine speed regulation system and method for intelligently regulating parameters. Background Art

[0002] In the power system, hydropower units undertake a large number of peak load and frequency regulation tasks. Hydropower units should adjust the guide vane opening or output power of hydropower units in a timely and rapid manner according to the grid dispatching requirements and grid frequency changes to meet the needs of grid active power balance and frequency regulation. For grid-connected hydropower units, in order to meet the regulation needs of the grid, the opening adjustment mode or power adjustment mode is generally used for adjustment. The traditional opening adjustment mode or power adjustment mode is a feedback control mode, which uses the difference between the target opening or power and the actual value to generate the turbine relay control output according to a certain power law. The traditional adjustment mode has high requirements for the adjustment parameter setting. When the control parameter is too large, oscillation and over-regulation are prone to occur; when the control parameter is small, the adjustment speed often cannot meet the requirements. In addition, due to the nonlinear influence of the turbine characteristics, especially when the operating head of the unit changes, a set of parameters often cannot meet the precise control of the unit and needs to be corrected.

[0003] At present, most hydroelectric generator sets use PID control parameters set based on one or several special operating conditions to achieve control. When setting parameters, an external simulation tester or traversal method is required. On this basis, the control parameters are simply switched according to the real-time operating condition parameters in order to improve the regulation ability of the unit under different operating conditions. However, due to the limitations of the speed governor parameter setting method, the overall regulation performance of the unit under different water heads is often difficult to guarantee. When the unit participates in the peak-shaving and frequency-regulating tasks, there is inevitably a conflict between the operating conditions of efficient utilization of water energy and the high-quality conditions of peak-shaving and frequency-regulating in scheduling.

[0004] Current units often use PID control parameter settings for special operating conditions. Under specific operating heads, the set PID parameters may cause a decrease in regulation performance.

[0005] When setting PID control parameters, an external simulation tester is required, which is not convenient for actual operation.

[0006] The parameter tuning is often done by trial and error, and there is a lack of fixed tuning algorithms. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a turbine speed control system and method with intelligent parameter adjustment, so as to improve the reliability of the speed measurement channel of the hydropower unit, ensure that the comprehensive speed value of the speed regulator is reasonable and effective, avoid unit speed fluctuations, and improve the stability of the operation of the hydropower unit.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a turbine speed control system with intelligent parameter adjustment, the speed control system includes a speed governor PLC control system and a unit simulation PLC system; during the parameter adjustment process, the speed governor PLC control system sends the head and opening given signals to the unit simulation PLC system, and the unit simulation PLC system feeds back the unit frequency, opening, and active power signals to the speed governor PLC control system; The links of the unit simulation PLC system include hydraulic amplification link, hydraulic actuator, main relay, guide vane system, turbine, generator and power grid; The method for building the unit simulation PLC system includes the following steps: SA1, build a simulation model in the simulation software; the hydraulic amplification link is a proportional link, the hydraulic actuator and the main relay are both first-order inertia links, the guide vane system is a main relay stroke-guide vane opening curve, the turbine is a head-opening-mechanical power curve, the generator is a second-order synchronous motor model, and the power grid is an infinite power grid model; SA2, converts the simulation model and solver into C language code through the code conversion module in the simulation software; SA3, design the interface input and output conversion interface in the PLC integrated development environment IDE, and upload the simulation model code and input and output interface code to the PLC together.

[0009] The PID automatic adjustment method of the turbine speed control system with intelligent adjustment parameters as described above comprises the following steps: SB1, the governor PLC control system outputs the current water head value and the guide vane setting step signal to the unit simulation PLC system, and the guide vane setting steps from the no-load opening to the 90% opening; SB2, the unit simulation PLC system calculates the guide vane opening curve Y(t) and active power curve P(t) during the regulation process and feeds back to the governor PLC control system; SB3, analyze the key characteristic quantities of the curve in the discrete system, and the PID parameter tuning methods of the opening mode and the power mode are consistent; SB4, based on the above step response characteristics, according to the lambda tuning method and the ZN tuning method, the ideal PID parameters are:

[0010] In the formula ; SB5, converts the ideal PID parameters into discrete parallel PID parameters in engineering: And the relationship between PID and ideal PID is:

[0011]

[0012] Converting the parallel PID to discrete form is:

[0013] Therefore, the calculation method of discrete parallel PID parameters is:

[0014] Substitute the formula in step 4 into the equation:

[0015] It is the final setting value of the PID of the final speed regulator control system.

[0016] In SB3, the specific feature quantity and its judgment basis include the following steps: SB3-1, by judging the conditions ; Determine the inflection point of the adjustment curve M(k1,Y[k1]) ; SB3-2, draw a tangent line to this point, its slope is (Y[k1]-Y[k1-1]) , the intersection point of the tangent and the no-load opening is N((Y [K1]-Y0) / (Y[k1]-Y[k1-1]),Y0) , where Y0 is the no-load opening; SB3-3, Adjusting System Delay ; Adjust system time coefficient ; Adjustment coefficient ; Where △%OP is the per unit value of the given quantity deviation, △%PV is the per unit value of the response quantity deviation; Y0 is the initial value of the response, Y SS To respond to stable values, both are per-unit values.

[0017] The parameter adjustment judgment logic of the turbine speed control system with intelligent parameter adjustment as described above includes the following steps: SC1, judge whether the water head value is 10m different from the water head value of the last PID parameter setting, or whether there is a parameter setting instruction. If yes, enter the parameter setting process, if not, the PID parameters remain unchanged; SC2, the setting process starts, the governor control system outputs the current head value and the guide vane setting step signal to the unit simulation system, and the guide vane setting steps from the no-load opening to 90% opening; SC3, the unit simulation system calculates the step response of the guide vane opening and the unit active power, and feeds it back to the speed governor control system; SC4, analyzes the key characteristic quantities of the curve in the discrete system and calculates the PID setting value of the speed regulator control system, assigns the corresponding values ​​to the power mode PID parameters and the opening mode PID parameters, and records the current water head and PID parameters.

[0018] The main beneficial effects of the present invention are: When receiving a parameter adjustment instruction or the water head changes beyond the set value, the speed governor PLC control system extracts the opening and power step response signals from the simulation system under the current conditions, and adjusts the PID parameters of the speed control system based on the Lambda setting method by analyzing the key indicators of the signal. This method can intelligently and accurately adjust the PID parameters of the speed control system under different water heads, improve the intelligence and accuracy of the speed control system adjustment, and provide guarantee for the safe and stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] Figure 1 This is a diagram of the speed regulator PLC control system of the present invention.

[0021] Figure 2 This is a model block diagram of the unit simulation system of the present invention.

[0022] Figure 3 A flow chart is constructed for the PLC-based unit simulation system of the present invention.

[0023] Figure 4 It is a schematic diagram of step response feature extraction of the present invention.

[0024] Figure 5 This is a logic diagram for intelligent adjustment of parameters of a turbine speed control system according to the present invention. DETAILED DESCRIPTION

[0025] like Figure 1~Figure 5 In the invention, a turbine speed regulating system with intelligent parameter adjustment is provided, wherein the speed regulating system includes a speed governor PLC control system and a unit simulation PLC system; during the parameter adjustment process, the speed governor PLC control system sends the head and opening given signals to the unit simulation PLC system, and the unit simulation PLC system feeds back the unit frequency, opening, and active power signals to the speed governor PLC control system; The links of the unit simulation PLC system include hydraulic amplification link, hydraulic actuator, main relay, guide vane system, turbine, generator and power grid.

[0026] Preferably, when a parameter adjustment instruction is received or the water head change exceeds the set value, the speed regulator PLC control system extracts the opening and power step response signals from the simulation system under the current conditions, and adjusts the PID parameters of the speed regulation system based on the Lambda tuning method by analyzing the key indicators of the signal.

[0027] In the preferred solution, the method for building a unit simulation PLC system includes the following steps: SA1, build a simulation model in the simulation software; the hydraulic amplification link is a proportional link, the hydraulic actuator and the main relay are both first-order inertia links, the guide vane system is a main relay stroke-guide vane opening curve, the turbine is a head-opening-mechanical power curve, the generator is a second-order synchronous motor model, and the power grid is an infinite power grid model; SA2, converts the simulation model and solver into C language code through the code conversion module in the simulation software; SA3, design the interface input and output conversion interface in the PLC integrated development environment IDE, and upload the simulation model code and input and output interface code to the PLC together.

[0028] In a preferred solution, the PID automatic adjustment method of the turbine speed control system with intelligent adjustment parameters as described above comprises the following steps: SB1, the governor PLC control system outputs the current water head value and the guide vane setting step signal to the unit simulation PLC system, and the guide vane setting steps from the no-load opening to the 90% opening; SB2, the unit simulation PLC system calculates the guide vane opening curve Y(t) and active power curve P(t) during the regulation process and feeds back to the governor PLC control system; SB3, analyze the key characteristic quantities of the curve in the discrete system, and the PID parameter tuning methods of the opening mode and the power mode are consistent; SB4, based on the above step response characteristics, according to the lambda tuning method and the ZN tuning method, the ideal PID parameters are:

[0029] In the formula ; SB5, converts the ideal PID parameters into discrete parallel PID parameters in engineering: And the relationship between PID and ideal PID is:

[0030]

[0031] Converting the parallel PID to discrete form is:

[0032] Therefore, the calculation method of discrete parallel PID parameters is:

[0033] Substitute the formula in step 4 into the equation:

[0034] It is the final setting value of the PID of the final speed regulator control system.

[0035] In the preferred solution, in SB3, the specific feature quantity and its judgment basis include the following steps: SB3-1, by judging the conditions ; Determine the inflection point of the adjustment curve M(k1,Y[k1]) ; SB3-2, draw a tangent line to this point, its slope is (Y[k1]-Y[k1-1]) , the intersection point of the tangent and the no-load opening is N((Y [K1]-Y0) / (Y[k1]-Y[k1-1]),Y0) , where Y0 is the no-load opening; SB3-3, Adjusting System Delay ; Adjust system time coefficient ; Adjustment coefficient ; Where △%OP is the per unit value of the given quantity deviation, △%PV is the per unit value of the response quantity deviation; Y0 is the initial value of the response, Y SS To respond to stable values, both are per-unit values.

[0036] In a preferred solution, the parameter adjustment judgment logic of the turbine speed control system with intelligent parameter adjustment as described above comprises the following steps: SC1, judge whether the water head value is 10m different from the water head value of the last PID parameter setting, or whether there is a parameter setting instruction. If yes, enter the parameter setting process, if not, the PID parameters remain unchanged; SC2, the setting process starts, the governor control system outputs the current head value and the guide vane setting step signal to the unit simulation system, and the guide vane setting steps from the no-load opening to 90% opening; SC3, the unit simulation system calculates the step response of the guide vane opening and the unit active power, and feeds it back to the speed governor control system; SC4, analyzes the key characteristic quantities of the curve in the discrete system and calculates the PID setting value of the speed regulator control system, assigns the corresponding values ​​to the power mode PID parameters and the opening mode PID parameters, and records the current water head and PID parameters.

[0037] In the above method, the PID parameters of the speed governor PLC control system are intelligently and accurately adjusted under different water heads, which improves the intelligence and accuracy of the speed governor PLC control system adjustment and provides guarantee for the safe and stable operation of the power system.

[0038] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A turbine speed control system with intelligent parameter adjustment, characterized by: The speed control system includes the speed governor PLC control system and the unit simulation PLC system; During the parameter adjustment process, the governor PLC control system sends the water head and opening given signals to the unit simulation PLC system, and the unit simulation PLC system feeds back the unit frequency, opening, and active power signals to the governor PLC control system; The links of the unit simulation PLC system include hydraulic amplification link, hydraulic actuator, main relay, guide vane system, turbine, generator and power grid; The method for building the unit simulation PLC system includes the following steps: SA1, build a simulation model in the simulation software; the hydraulic amplification link is a proportional link, the hydraulic actuator and the main relay are both first-order inertia links, the guide vane system is a main relay stroke-guide vane opening curve, the turbine is a head-opening-mechanical power curve, the generator is a second-order synchronous motor model, and the power grid is an infinite power grid model; SA2, converts the simulation model and solver into C language code through the code conversion module in the simulation software; SA3, design the interface input and output conversion interface in the PLC integrated development environment IDE, and upload the simulation model code and input and output interface code to the PLC together.

2. The PID automatic adjustment method of the turbine speed control system with intelligent adjustment parameters according to claim 1 is characterized in that: The steps include: SB1, the governor PLC control system outputs the current water head value and the guide vane setting step signal to the unit simulation PLC system, and the guide vane setting steps from the no-load opening to the 90% opening; SB2, the unit simulation PLC system calculates the guide vane opening curve Y(t) and active power curve P(t) during the regulation process and feeds back to the governor PLC control system; SB3, analyze the key characteristic quantities of the curve in the discrete system, and the PID parameter tuning methods of the opening mode and the power mode are consistent; SB4, based on the above step response characteristics, according to the lambda tuning method and the ZN tuning method, the ideal PID parameters are: In the formula ; SB5, converts the ideal PID parameters into discrete parallel PID parameters in engineering: And the relationship between PID and ideal PID is: Converting the parallel PID to discrete form is: Therefore, the calculation method of discrete parallel PID parameters is: Substitute the formula in step 4 into the equation: It is the final setting value of the PID of the final speed regulator control system.

3. The PID automatic adjustment method of the turbine speed control system with intelligent adjustment parameters according to claim 2 is characterized in that: In SB3, the specific feature quantity and its judgment basis include the following steps: SB3-1, by judging the conditions ; Determine the inflection point of the adjustment curve M (k1,Y[k1]) ; SB3-2, draw a tangent line at this point, its slope is (Y[k1]-Y[k1-1]) , the intersection point of the tangent and the no-load opening is N((Y [K1]-Y0) / (Y[k1]-Y[k1-1]),Y0) , where Y0 is the no-load opening; SB3-3, Adjusting System Delay ; Adjust system time coefficient ; Adjustment coefficient ; Where △%OP is the per unit value of the given quantity deviation, △%PV is the per unit value of the response quantity deviation; Y0 is the initial value of the response, Y SS To respond to stable values, both are per-unit values.

4. The parameter adjustment judgment logic of the turbine speed control system with intelligent parameter adjustment according to claim 1 is characterized in that: The steps include: SC1, judge whether the water head value is 10m different from the water head value of the last PID parameter setting, or whether there is a parameter setting instruction. If yes, enter the parameter setting process, if not, the PID parameters remain unchanged; SC2, the setting process starts, the governor control system outputs the current head value and the guide vane setting step signal to the unit simulation system, and the guide vane setting steps from the no-load opening to 90% opening; SC3, the unit simulation system calculates the step response of the guide vane opening and the unit active power, and feeds it back to the speed governor control system; SC4, analyzes the key characteristic quantities of the curve in the discrete system and calculates the PID setting value of the speed regulator control system, assigns the corresponding values ​​to the power mode PID parameters and the opening mode PID parameters, and records the current water head and PID parameters.

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