Control method and device for thermal oil circulation pump group of trough type solar thermal power station

Abstract

The present application discloses a control method and device for a thermal oil circulation pump group of a trough type solar thermal power station, wherein the method includes: obtaining the thermal oil pressure at the pump inlet, the thermal oil pressure at the pump outlet, and the saturated steam pressure of the thermal oil at the pump inlet at the current temperature of the thermal oil circulation pump; calculating the current effective NPSH according to the thermal oil pressure at the pump inlet and the saturated steam pressure of the thermal oil at the pump inlet at the current temperature; calculating the first pump group head according to the thermal oil pressure at the pump inlet and the thermal oil pressure at the pump outlet; generating a control strategy for the thermal oil circulation pump group according to the current effective NPSH and / or the first pump group head. The control method and device for the thermal oil circulation pump group of a trough type solar thermal power station of the embodiment of the present application can effectively improve the automation level of the pump group, optimize the operating characteristics of the pump group, reduce the frequency of unnecessary shutdowns while strengthening necessary shutdown protection, improve the efficiency of the power station and power generation, and effectively reduce the operation and maintenance costs.

Description

Technical Field

[0001] The present application relates to the technical field of control of circulating pump groups in trough-type solar thermal power plants, and in particular to a control method and device for a heat transfer oil circulating pump group in a trough-type solar thermal power plant. Background Art

[0002] The control strategy of solar thermal power generation system is one of the key core technologies of this type of power station. It maintains the safe operation and regulation of the power station through automated integrated control, thereby ensuring that the equipment and system are in a safe state and reducing the workload of operators. And through local automatic switching of process flow, it reduces energy waste during power station regulation, thereby improving the economic efficiency of the power station.

[0003] At present, the control technology of trough-type solar thermal power plants is still in the hands of a few foreign companies. The relevant technology has been commercially applied in foreign countries for more than 30 years, but it is still in its infancy in China. Due to the large differences between foreign countries and my country in terms of power grid architecture, dispatching strategy and operating characteristics, the power station control strategy needs to be transformed according to the characteristics and needs of the domestic power grid. As a core technology that is vacant in China and monopolized by foreign countries, it faces the problem of high procurement costs and the inability to be fully replicated.

[0004] As one of the core systems for maintaining the circulation of thermal oil throughout the site, the technical performance and quality of the thermal oil circulation pump unit are crucial to the economic efficiency of the normal production of the power plant. On the one hand, if the operating parameters of the pump unit deviate from the design capacity, it will bring great hidden dangers to the safe operation of the pump unit and the supporting systems before and after, threatening the production safety of the power plant and failing to reach the design life. On the other hand, the continuous operation of the pump unit has a significant impact on the power generation capacity of the power plant. If the forced shutdown rate increases due to unreasonable pump unit safety protection strategy, it will lead to frequent shutdowns of power plant production and it will be difficult to achieve ideal benefits.

[0005] Due to the small number of large-scale commercial trough power plants in operation in China, relevant information on the operation and protection of thermal oil pump units is currently lacking. According to foreign experience and cases, the rationality of a series of safety protection strategies such as the NPSH and flow head performance of the thermal oil circulating pump unit will directly affect the continuous operation capacity and forced shutdown times of the thermal oil circulating pump unit, and thus affect the annual operation hours of the power station. Therefore, seeking a reasonable protection strategy for the thermal oil circulating pump unit is particularly necessary for expensive CSP power plants. Summary of the invention

[0006] The purpose of this application is to solve one of the above-mentioned technical problems at least to a certain extent.

[0007] To this end, the first purpose of the present invention is to propose a control method for a thermal oil circulation pump group of a trough type solar thermal power station. Under the premise of ensuring safety and reliability, a reasonable process configuration and a matching automation protection strategy are adopted to effectively improve the automation level of the pump group, optimize the operating characteristics of the pump group, and reduce the frequency of unnecessary shutdowns while strengthening necessary shutdown protection, ultimately improving the power station and power generation efficiency and effectively reducing operation and maintenance costs.

[0008] The second objective of the present application is to provide a control device for a thermal oil circulation pump group of a trough type solar thermal power station.

[0009] The third objective of the present application is to provide an electronic device.

[0010] A fourth objective of the present application is to provide a computer-readable storage medium.

[0011] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a control method for a thermal oil circulation pump group of a trough-type solar thermal power station, comprising:

[0012] Obtain the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet of the heat transfer oil circulation pump and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature;

[0013] Calculate the current effective NPSH according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature;

[0014] Calculating the lift of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet;

[0015] A control strategy for the thermal oil circulation pump group is generated according to the current effective NPSH and / or the head of the first pump group.

[0016] Optionally, the current effective NPSH is calculated according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature, including:

[0017] The current effective NPSH is calculated based on Formula 1: 泵入口 / ρg)-(P 导热油饱和蒸汽 / ρg), where NPSHa is the current effective NPSH, P 泵入口 is the heat transfer oil pressure at the pump inlet, P 导热油饱和蒸汽 is the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature, ρ is the density of the heat transfer oil at the pump inlet, and g is the acceleration of gravity.

[0018] Optionally, calculating the head of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet includes:

[0019] The head of the first pump group is calculated based on Formula 2: 泵出口 -P 泵入口 ) / ρg, where H1 is the head of the first pump group, P 泵出口 is the heat transfer oil pressure at the pump outlet, P 泵入口 is the heat transfer oil pressure at the pump inlet, ρ is the heat transfer oil density at the pump inlet, and g is the gravitational acceleration.

[0020] Optionally, generating a control strategy for the thermal oil circulation pump group according to the current effective NPSH and / or the head of the first pump group includes:

[0021] Compare the current effective NPSHHa with the preset required NPSHr;

[0022] If 1.5*NPSHr≤NPSHHa<2*NPSHr, an alarm message is generated, and a first control strategy is generated;

[0023] If NPSHa<1.5*NPSHr, the thermal oil circulation pump group is controlled to shut down.

[0024] Optionally, the first control strategy includes at least one of the following: increasing the heat transfer oil pressure at the pump inlet; increasing the heat transfer oil liquid level at the pump inlet; and reducing the rotation speed of the heat transfer oil circulation pump.

[0025] Optionally, generating a control strategy for the thermal oil circulation pump group according to the current effective NPSH and / or the head of the first pump group includes:

[0026] The lift H1 of the first pump group is respectively equal to the upper limit value H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons;

[0027] If H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation;

[0028] If H 上限2

[0029] If H 下限1 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed;

[0030] If H1<H 下限1 ​​​, then the thermal oil circulation pump group is controlled to shut down.

[0031] Optionally, the method further includes:

[0032] Determine the head-flow relationship H=a1Q of the heat transfer oil circulation pump group when the speed is n 4 +a2Q 3 +a3Q 2 +a4Q+…, where H is the head, Q is the flow rate, a1, a2, a3, a4 are preset coefficients, Q is proportional to the change of n, and H is proportional to the square of the change of n;

[0033] Select the head H0 of the second pump group corresponding to the preset speed n0;

[0034] The head H0 of the second pump group is respectively equal to the upper limit value H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons;

[0035] If H 上限1 <H0<H 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation;

[0036] If H 上限2 <H0, the heat transfer oil circulation pump group is controlled to stop;

[0037] If H 下限1 <H0<H 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed;

[0038] If H0<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0039] Optionally, the method further includes:

[0040] If NPSHa>2*NPSHr, the head H1 of the first pump group is further compared with the first head upper limit H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons;

[0041] If H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; ​

[0042] If H 上限2

[0043] If H 下限1 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed;

[0044] If H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0045] The control method of the thermal oil circulation pump group of the trough type solar thermal power station in the embodiment of the present application calculates the current effective NPSH and the first pump group head by obtaining the thermal oil pressure at the pump inlet, the thermal oil pressure at the pump outlet and the saturated steam pressure of the thermal oil at the pump inlet at the current temperature of the thermal oil circulation pump, and then generates a control strategy for the thermal oil circulation pump group based on the calculated current effective NPSH and / or the first pump group head. This can effectively improve the automation level of the pump group, optimize the operating characteristics of the pump group, reduce the frequency of unnecessary shutdowns while strengthening necessary shutdown protection, improve the power station and power generation efficiency and effectively reduce operation and maintenance costs.

[0046] To achieve the above-mentioned purpose, the second embodiment of the present application proposes a control device for a thermal oil circulation pump group of a trough-type solar thermal power station, comprising:

[0047] An acquisition module is used to obtain the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet of the heat transfer oil circulation pump and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature;

[0048] A first calculation module is used to calculate the current effective NPSH according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature;

[0049] A second calculation module is used to calculate the head of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet;

[0050] A control module is used to generate a control strategy for the thermal oil circulation pump group according to the current effective NPSH and / or the head of the first pump group.

[0051] Optionally, the first computing module is used to:

[0052] The current effective NPSH is calculated based on Formula 1: 泵入口 / ρg)-(P 导热油饱和蒸汽 / ρg), where NPSHa is the current effective NPSH, P 泵入口 is the heat transfer oil pressure at the pump inlet, P 导热油饱和蒸汽 ​​is the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature, ρ is the density of the heat transfer oil at the pump inlet, and g is the acceleration of gravity.

[0053] Optionally, the second computing module is used to:

[0054] The head of the first pump group is calculated based on Formula 2: 泵出口 -P 泵入口 ) / ρg, where H1 is the head of the first pump group, P 泵出口 is the heat transfer oil pressure at the pump outlet, P 泵入口 is the heat transfer oil pressure at the pump inlet, ρ is the heat transfer oil density at the pump inlet, and g is the gravitational acceleration.

[0055] Optionally, the control module is used to:

[0056] Compare the current effective NPSHHa with the preset required NPSHr;

[0057] If 1.5*NPSHr≤NPSHHa<2*NPSHr, an alarm message is generated, and a first control strategy is generated;

[0058] If NPSHa<1.5*NPSHr, the thermal oil circulation pump group is controlled to shut down.

[0059] Optionally, the first control strategy includes at least one of the following: increasing the heat transfer oil pressure at the pump inlet; increasing the heat transfer oil liquid level at the pump inlet; and reducing the rotation speed of the heat transfer oil circulation pump.

[0060] Optionally, the control module is used to:

[0061] The lift H1 of the first pump group is respectively equal to the upper limit value H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons;

[0062] If H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation;

[0063] If H 上限2

[0064] If H 下限1 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed; ​​​

[0065] If H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0066] Optionally, the device further comprises:

[0067] Determination module, used to determine the head-flow relationship H=a1Q of the heat transfer oil circulation pump group when the speed is n 4 +a2Q 3 +a3Q 2 +a4Q+…, where H is the head, Q is the flow rate, a1, a2, a3, a4 are preset coefficients, Q is proportional to the change of n, and H is proportional to the square of the change of n;

[0068] A selection module, used to select the head H0 of the second pump group corresponding to the preset speed n0;

[0069] The control module is also used to compare the lift H0 of the second pump group with the upper limit value H0 of the first lift. 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons;

[0070] If H 上限1 <H0<H 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation;

[0071] If H 上限2 <H0, the heat transfer oil circulation pump group is controlled to stop;

[0072] If H 下限1 <H0<H 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed;

[0073] If H0<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0074] Optionally, the control module is further used to:

[0075] If NPSHa>2*NPSHr, the head H1 of the first pump group is further compared with the first head upper limit H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons;

[0076] If H 上限1 <H1<H上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation;

[0077] If H 上限2

[0078] If H 下限1 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed;

[0079] If H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0080] The control device of the thermal oil circulation pump group of the trough type solar thermal power station in the embodiment of the present application calculates the current effective NPSH and the first pump group head by obtaining the thermal oil pressure at the pump inlet and the pump outlet of the thermal oil circulation pump and the saturated steam pressure of the thermal oil at the current temperature of the pump inlet, and then generates a control strategy for the thermal oil circulation pump group based on the calculated current effective NPSH and / or the first pump group head. This can effectively improve the automation level of the pump group, optimize the operating characteristics of the pump group, reduce the frequency of unnecessary shutdowns while strengthening necessary shutdown protection, improve the power station and power generation efficiency, and effectively reduce operation and maintenance costs.

[0081] To achieve the above-mentioned objectives, the third aspect embodiment of the present application proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the control method of the thermal oil circulation pump group of the trough-type solar thermal power station of the first aspect embodiment of the present application is implemented.

[0082] To achieve the above objectives, the fourth aspect of the present application provides a computer-readable storage medium. When the computer program is executed by the processor, the control method of the thermal oil circulation pump group of the trough-type solar thermal power station of the first aspect of the present application is implemented.

[0083] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0085] Figure 1 A flow chart of a control method of a thermal oil circulation pump group of a trough-type solar thermal power station according to an embodiment is shown; ​​

[0086] Figure 2 A schematic diagram of the effect of the permitted operation area of ​​an embodiment is presented;

[0087] Figure 3 A flow chart of a control method of a thermal oil circulation pump group of a trough-type CSP power station according to another embodiment is shown;

[0088] Figure 4 A schematic structural diagram of a control device for a thermal oil circulation pump group of a trough-type CSP power station according to an embodiment is shown;

[0089] Figure 5 A structural schematic diagram of a control device for a thermal oil circulation pump group of a trough-type solar thermal power station according to another embodiment is shown. DETAILED DESCRIPTION

[0090] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0091] The present invention is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention.

[0092] The following describes a control method and device for a thermal oil circulation pump group in a trough-type solar thermal power station according to an embodiment of the present application with reference to the accompanying drawings.

[0093] Figure 1 : is a flow chart of a control method of a thermal oil circulation pump group of a trough type CSP power station according to an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0094] S1, obtaining the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet of the heat transfer oil circulation pump and the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature.

[0095] The thermal oil circulation pump is the core conveying equipment to maintain the circulation of thermal oil between the main process systems such as the solar field, steam generation system, and heat storage system. Therefore, its operating status should be monitored to prevent it from deviating from the operating area or permitted operating parameters, causing damage to the pump equipment. Important operating parameters of the thermal oil circulation pump may include the pump inlet thermal oil pressure P 泵入口 , Pump outlet heat transfer oil pressure P 泵出口 And the saturated vapor pressure P of the heat transfer oil at the pump inlet at the current temperature 导热油饱和蒸汽 The pressure can be detected by the pressure sensor at the corresponding position.

[0096] S2, calculating the current effective NPSH according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature.

[0097] Specifically, the current effective NPSH can be calculated based on Formula 1: 泵入口 / ρg)-(P 导热油饱和蒸汽 / ρg). Among them, NPSHa is the current effective cavitation margin, P 泵入口 is the heat transfer oil pressure at the pump inlet, P 导热油饱和蒸汽 is the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature, ρ is the density of the heat transfer oil at the pump inlet, and g is the acceleration of gravity.

[0098] S3, calculating the lift of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet.

[0099] Specifically, the lift of the first pump group can be calculated based on Formula 2: 泵出口 -P 泵入口 ) / ρg. Among them, H1 is the head of the first pump group, P 泵出口 is the heat transfer oil pressure at the pump outlet, P 泵入口 is the heat transfer oil pressure at the pump inlet, ρ is the heat transfer oil density at the pump inlet, and g is the acceleration of gravity. The pressure unit is MPa, and the density unit is kg / m 3 The heat transfer oil density ρ can be selected or calculated based on the heat transfer oil enthalpy entropy diagram or physical property calculation formula provided by the heat transfer oil manufacturer. In this embodiment, biphenyl-diphenyl ether type heat transfer oil is selected.

[0100] S4: Generate a control strategy for the thermal oil circulation pump group according to the current effective NPSH and / or the head of the first pump group.

[0101] Specifically, there are three ways to generate a control strategy for the thermal oil circulation pump group.

[0102] The first method is to consider the current effective NPSH alone.

[0103] The pump cavitation margin is one of the parameters that must be fully protected for the thermal oil circulation pump. When the effective cavitation margin during the operation phase is lower than the required cavitation margin, the circulation pump will cavitate and cause huge losses. Since the operating temperature of the thermal oil exceeds the boiling point at normal pressure and the pre-tank (expansion tank) of the circulation pump is nitrogen-sealed and pressurized, in order to reduce the daily nitrogen loss of the expansion tank, the expansion tank adopts a constant pressure + range adjustment instead of the traditional constant pressure operation strategy. When the pressure of the expansion tank is not regulated in time or fails, and the pressure in the tank fluctuates downward, there is a potential risk that the thermal oil pressure at the pump inlet is too low and the pump cavitation occurs. Therefore, it is necessary to monitor the pump cavitation margin and control the thermal oil circulation pump according to the cavitation margin.

[0104] Specifically, the current effective NPSHHa is compared with the preset required NPSHr. If 1.5*NPSHr≤NPSHHa<2*NPSHr, an alarm message is generated, and a first control strategy is generated; if NPSHa<1.5*NPSHr, the thermal oil circulation pump group is controlled to shut down.

[0105] The first control strategy includes at least one of the following: increasing the heat transfer oil pressure at the pump inlet; increasing the heat transfer oil level at the pump inlet; reducing the speed of the heat transfer oil circulation pump. The above methods can increase the current effective NPSH and ensure the normal operation of the heat transfer oil circulation pump group.

[0106] Among them, when the heat transfer oil expands due to heat during the circulation process, the excess volume after expansion flows to the overflow tank through the overflow port of the expansion tank; when the heat transfer oil cools down and shrinks, it is necessary to start the oil replenishment pump to transport the heat transfer oil in the overflow tank to the expansion tank to maintain the heat transfer oil level of the circulation pump.

[0107] The second method: consider the pump head alone.

[0108] The permissible operating area of ​​the pump in the flow-head-speed curve is one of the important monitoring indicators for the healthy operation of the thermal oil circulating pump. Therefore, the pump outlet main pipe is equipped with a minimum flow pipeline for the thermal oil circulating pump and a matching regulating valve to ensure that the pump flow-head meets the permissible operating area (such as Figure 2 When the thermal oil circulation pumps are connected in parallel, the heads of the pumps in the pump group are the same, and the flow rate of a single pump is equal to the total flow rate of the pump group divided by the number of pumps connected in parallel. When the pressure difference between the inlet and outlet of the thermal oil pump group reaches Figure 2 When the minimum flow / highest head point corresponding to the speed is reached, the low flow regulating valve will be automatically opened and PID regulation will be started to increase the flow of thermal oil and reduce the pressure difference between the inlet and outlet of the pump. Conversely, if the low flow regulating valve is opened and the flow of thermal oil reaches the maximum flow / lowest head point corresponding to the current speed, the valve opening will be automatically reduced until it is closed.

[0109] Specifically, the first pump head H1 is respectively compared with the first head upper limit H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 For comparison. If H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; if H 上限2 下限1 下限2 ​​​, an alarm message is generated and the low flow regulating valve of the thermal oil circulation pump is closed; if H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0110] The third method: first judge by the NPSH and then by the pump head.

[0111] That is to say, when the NPSH is normal, it is determined whether the pump head is normal, and the corresponding control strategy is generated accordingly.

[0112] Specifically, if NPSHa>2*NPSHr (normal), the first pump head H1 is further compared with the first head upper limit H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 For comparison. If H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; if H 上限2 下限1 下限2 , an alarm message is generated and the low flow regulating valve of the thermal oil circulation pump is closed; if H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0113] The control method of the thermal oil circulation pump group of the trough type solar thermal power station in the embodiment of the present application calculates the current effective NPSH and the first pump group head by obtaining the thermal oil pressure at the pump inlet, the thermal oil pressure at the pump outlet and the saturated steam pressure of the thermal oil at the pump inlet at the current temperature of the thermal oil circulation pump, and then generates a control strategy for the thermal oil circulation pump group based on the calculated current effective NPSH and / or the first pump group head. This can effectively improve the automation level of the pump group, optimize the operating characteristics of the pump group, reduce the frequency of unnecessary shutdowns while strengthening necessary shutdown protection, improve the power station and power generation efficiency and effectively reduce operation and maintenance costs.

[0114] In another embodiment of the present application, Figure 3 As shown, the control method of the thermal oil circulation pump group of the trough type CSP power station also includes:

[0115] S5, determine the head-flow relationship H=a1Q of the heat transfer oil circulation pump group when the speed is n 4 +a2Q 3 +a3Q 2 +a4Q+….

[0116] ​​​Where H is the head in m; Q is the flow rate; a1, a2, a3, a4 are preset coefficients. The preset coefficients a1, a2, a3, a4 can be determined based on the QH line characteristics of the circulating pump at a given speed n0, or can be directly obtained by the flow meter (the quantity and quality of the flow meter must be guaranteed to eliminate the factors affecting fluctuations and errors).

[0117] When the speed n changes, Q is proportional to the change in n, and H is proportional to the square of the change in n, thus generating a head-flow relationship corresponding to the change. That is, n i Corresponding to Q i and H i .

[0118] S6, selecting the head H0 of the second pump group corresponding to the preset speed n0.

[0119] The head of the second pump group obtained in this way can verify whether the head of the first pump group calculated by actually measuring the thermal oil pressure at the pump inlet and the thermal oil pressure at the pump outlet is accurate.

[0120] S7, the lift H0 of the second pump group is respectively compared with the upper limit value H of the first lift. 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make a comparison.

[0121] S8, if H 上限1 <H0<H 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation.

[0122] S9, if H 上限2 <H0, the heat transfer oil circulation pump group is controlled to shut down.

[0123] S10, if H 下限1 <H0<H 下限2 , an alarm message is generated and the low flow regulating valve of the thermal oil circulation pump is closed.

[0124] S11, if H0<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0125] Figure 2 H 上限1 , H 上限2 , H 下限1 , H 下限2 It can be calculated by Q=αH+β, where the coefficients α and β can be calculated and determined based on typical points on the permissible operating boundary or the alarm boundary.

[0126] For example, substitute the operating parameters into the linear relationship Q1=α1*H1+β1, Q2=α2*H2+β2 for calculation. When the actual H value exceeds the H1 value (or the actual Q value is lower than the Q1 value), it is determined that the circulating pump has too high a head and too low a flow rate. If the actual value crosses the α2 line (corresponding to continuous operation permission), an alarm is triggered and the low flow regulating valve of the pump group is automatically opened to enter PID tracking regulation; if it crosses the α1 line (corresponding to short-term operation permission), the pump group shutdown protection is triggered.

[0127] For another example, substitute the operating parameters into the linear relationship Q3 = α3*H3 + β3, Q4 = α4*H4 + β4 for calculation. When the actual H value is lower than the H4 value (or the actual Q value exceeds the Q4 value), it is determined that the circulation pump has too large a flow rate and low head. If the actual value crosses the α4 line, an alarm is triggered. At this time, the low flow regulating valve of the pump group will automatically close if it is open; if it crosses the α3 line, the pump group shutdown protection is triggered.

[0128] Figure 2 The speed range is also shown, such as the lowest permissible speed line at the bottom and the highest permissible speed line at the top. The head H0 and flow Q0 of the second pump group corresponding to the speed n0 are:

[0129] When the whole set of protection strategies is put into operation, the operator only needs to set the external demand flow of the pump, and it can automatically control the continuous and stable operation within the AOA / ROA area. The automatic tracking of external demand by the automation control group can further enhance the automation capability.

[0130] In order to implement the above-mentioned embodiment, the present application also proposes a control device for a thermal oil circulation pump group of a trough-type solar thermal power station.

[0131] Figure 4 It is a structural schematic diagram of a control device for a thermal oil circulation pump group of a trough type solar thermal power station according to an embodiment of the present application.

[0132] like Figure 4 As shown, the control device of the thermal oil circulation pump group of the trough type solar thermal power station includes an acquisition module 41, a first calculation module 42, a second calculation module 43 and a control module 44.

[0133] The acquisition module 41 is used to acquire the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet of the heat transfer oil circulation pump and the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature.

[0134] The first calculation module 42 is used to calculate the current effective NPSH according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature.

[0135] The first calculation module 42 is used to calculate the current effective NPSH based on Formula 1:泵入口 / ρg)-(P 导热油饱和蒸汽 / ρg), where NPSHa is the current effective NPSH, P 泵入口 is the heat transfer oil pressure at the pump inlet, P 导热油饱和蒸汽 is the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature, ρ is the density of the heat transfer oil at the pump inlet, and g is the acceleration of gravity.

[0136] The second calculation module 43 is used to calculate the lift of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet.

[0137] The second calculation module 43 is used to calculate the head of the first pump group based on Formula 2: H1 = (P 泵出口 -P 泵入口 ) / ρg, where H1 is the head of the first pump group, P 泵出口 is the heat transfer oil pressure at the pump outlet, P 泵入口 is the heat transfer oil pressure at the pump inlet, ρ is the heat transfer oil density at the pump inlet, and g is the gravitational acceleration.

[0138] The control module 44 is used to generate a control strategy for the thermal oil circulation pump group according to the current effective NPSH and / or the head of the first pump group.

[0139] The control module 44 is used to compare the current effective NPSHHa with the preset required NPSHr; if 1.5*NPSHr≤NPSHHa<2*NPSHr, generate an alarm message and generate a first control strategy; if NPSHa<1.5*NPSHr, control the thermal oil circulation pump group to shut down. The first control strategy includes at least one of the following: increase the thermal oil pressure at the pump inlet; increase the thermal oil level at the pump inlet; reduce the speed of the thermal oil circulation pump.

[0140] The control module 44 is used to: compare the first pump group head H1 with the first head upper limit H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Compare; if H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; if H 上限2 下限1 下限2 , an alarm message is generated and the low flow regulating valve of the thermal oil circulation pump is closed; if H1<H 下限1 ​​​, then the thermal oil circulation pump group is controlled to shut down.

[0141] The control module 44 is further configured to: if NPSHa>2*NPSHr, further compare the first pump group head H1 with the first head upper limit H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Compare; if H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; if H 上限2 下限1 下限2 , an alarm message is generated and the low flow regulating valve of the thermal oil circulation pump is closed; if H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0142] In addition, if Figure 5 As shown, in another embodiment, the device further includes a determination module 45 and a selection module 46.

[0143] Determination module 45, used to determine the head-flow relationship H=a1Q of the heat transfer oil circulation pump group when the speed is n 4 +a2Q 3 +a3Q 2 +a4Q+… Among them, H is the head, Q is the flow rate, a1, a2, a3, a4 are preset coefficients, Q is proportional to the change of n, and H is proportional to the square of the change of n.

[0144] The selection module 46 is used to select the head H0 of the second pump group corresponding to the preset speed n0.

[0145] The control module 44 is also used to compare the lift H0 of the second pump group with the first lift upper limit H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Compare; if H 上限1 <H0<H 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; if H 上限2 <H0, the heat transfer oil circulation pump group is controlled to stop; if H 下限1 <H0<H 下限2 ​​​, an alarm message is generated and the low flow regulating valve of the thermal oil circulation pump is closed; if H0<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

[0146] It should be understood that the control device of the thermal oil circulation pump group of the trough type solar thermal power station is consistent with the description of the control method embodiment of the corresponding thermal oil circulation pump group of the trough type solar thermal power station, so it will not be repeated in this embodiment.

[0147] The control device of the thermal oil circulation pump group of the trough type solar thermal power station in the embodiment of the present application calculates the current effective NPSH and the first pump group head by obtaining the thermal oil pressure at the pump inlet and the pump outlet of the thermal oil circulation pump and the saturated steam pressure of the thermal oil at the current temperature of the pump inlet, and then generates a control strategy for the thermal oil circulation pump group based on the calculated current effective NPSH and / or the first pump group head. This can effectively improve the automation level of the pump group, optimize the operating characteristics of the pump group, reduce the frequency of unnecessary shutdowns while strengthening necessary shutdown protection, improve the power station and power generation efficiency, and effectively reduce operation and maintenance costs.

[0148] In order to implement the above embodiments, the present application also proposes a computer device.

[0149] The computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a control method for a thermal oil circulation pump group of a trough-type solar thermal power station according to the first embodiment is implemented.

[0150] In order to implement the above embodiments, the present application also proposes a computer-readable storage medium.

[0151] The computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, a control method for a thermal oil circulation pump group of a trough-type solar thermal power station according to the first embodiment is implemented.

[0152] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0153] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing in a suitable manner if necessary, and then stored in a computer memory.

[0154] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0155] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Claims

1. A control method for a thermal oil circulation pump group of a trough type solar thermal power station, characterized in that: include: Obtain the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet of the heat transfer oil circulation pump and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature; Calculate the current effective NPSH according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature; Calculating the lift of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet; generating a control strategy for the thermal oil circulation pump group according to the current effective NPSH and the head of the first pump group; Generating a control strategy for the thermal oil circulation pump group according to the current effective NPSH and the head of the first pump group includes: Compare the current effective NPSHHa with the preset required NPSHr; If 1.5*NPSHr≤NPSHHa<2*NPSHr, an alarm message is generated, and a first control strategy is generated; If NPSHa<1.5*NPSHr, the thermal oil circulation pump group is controlled to shut down; If NPSHa>2*NPSHr, then the head H1 of the first pump group is further compared with the upper limit value H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons; If H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation;​ If H 上限2 <H1, the heat transfer oil circulation pump group is controlled to stop; If H 下限1 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed;​ If H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

2. The method according to claim 1, characterized in that: The current effective NPSH is calculated according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature, including: The current effective NPSH is calculated based on Formula 1: 泵入口 / ρg)-(P 导热油饱和蒸汽 / ρg), where NPSHa is the current effective NPSH, P 泵入口 is the heat transfer oil pressure at the pump inlet, P 导热油饱和蒸汽 is the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature, ρ is the density of the heat transfer oil at the pump inlet, and g is the acceleration of gravity.

3. The method according to claim 1, characterized in that Calculating the head of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet includes: The head of the first pump group is calculated based on Formula 2: 泵出口 -P 泵入口 ) / ρg, where H1 is the head of the first pump group, P 泵出口 is the heat transfer oil pressure at the pump outlet, P 泵入口 is the heat transfer oil pressure at the pump inlet, ρ is the heat transfer oil density at the pump inlet, and g is the gravitational acceleration.

4. The method according to claim 1, characterized in that The first control strategy includes at least one of the following: Increasing the heat transfer oil pressure at the pump inlet; Increase the thermal oil level at the pump inlet; Reduce the speed of the thermal oil circulation pump.

5. The method according to claim 1, characterized in that: Also includes: Determine the head-flow relationship H=a1Q of the heat transfer oil circulation pump group when the speed is n 4 +a2Q 3 +a3Q 2 +a4Q+…, where H is the head, Q is the flow rate, a1, a2, a3, a4 are preset coefficients, Q is proportional to the change of n, and H is proportional to the square of the change of n; Select the head H0 of the second pump group corresponding to the preset speed n0; The head H0 of the second pump group is respectively equal to the upper limit value H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons; If H 上限1 <H0<H 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; If H 上限2 <H0, the heat transfer oil circulation pump group is controlled to stop; If H 下限1 <H0<H 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed; If H0<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

6. A control device for a thermal oil circulation pump group of a trough-type solar thermal power station, characterized in that: include: An acquisition module is used to obtain the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet of the heat transfer oil circulation pump and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature; A first calculation module is used to calculate the current effective NPSH according to the heat transfer oil pressure at the pump inlet and the saturated steam pressure of the heat transfer oil at the pump inlet at the current temperature; A second calculation module is used to calculate the head of the first pump group according to the heat transfer oil pressure at the pump inlet and the heat transfer oil pressure at the pump outlet; A control module, configured to generate a control strategy for the thermal oil circulation pump group according to the current effective NPSH and the head of the first pump group; The control module is used to compare the current effective NPSHHa with the preset required NPSHr; If 1.5*NPSHr≤NPSHHa<2*NPSHr, an alarm message is generated, and a first control strategy is generated; If NPSHa<1.5*NPSHr, the thermal oil circulation pump group is controlled to shut down; If NPSHa>2*NPSHr, then the head H1 of the first pump group is further compared with the upper limit value H 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons; If H 上限1 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation;​ If H 上限2 <H1, the heat transfer oil circulation pump group is controlled to stop; If H 下限1 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed;​ If H1<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

7. The device according to claim 6, characterized in that The first computing module is used for: The current effective NPSH is calculated based on Formula 1: 泵入口 / ρg)-(P 导热油饱和蒸汽 / ρg), where NPSHa is the current effective NPSH, P 泵入口 is the heat transfer oil pressure at the pump inlet, P 导热油饱和蒸汽 is the saturated vapor pressure of the heat transfer oil at the pump inlet at the current temperature, ρ is the density of the heat transfer oil at the pump inlet, and g is the acceleration of gravity.

8. The device according to claim 6, characterized in that The second computing module is used for: The head of the first pump group is calculated based on Formula 2: 泵出口 -P 泵入口 ) / ρg, where H1 is the head of the first pump group, P 泵出口 is the heat transfer oil pressure at the pump outlet, P 泵入口 is the heat transfer oil pressure at the pump inlet, ρ is the heat transfer oil density at the pump inlet, and g is the gravitational acceleration.

9. The device according to claim 6, characterized in that The first control strategy includes at least one of the following: Increasing the heat transfer oil pressure at the pump inlet; Increase the thermal oil level at the pump inlet; Reduce the speed of the thermal oil circulation pump.

10. The device according to claim 6, characterized in that The device also includes: Determination module, used to determine the head-flow relationship H=a1Q of the heat transfer oil circulation pump group when the speed is n 4 +a2Q 3 +a3Q 2 +a4Q+…, where H is the head, Q is the flow rate, a1, a2, a3, a4 are preset coefficients, Q is proportional to the change of n, and H is proportional to the square of the change of n; A selection module, used to select the head H0 of the second pump group corresponding to the preset speed n0; The control module is also used to compare the lift H0 of the second pump group with the upper limit value H0 of the first lift. 上限1 , The second lift upper limit value H 上限2 , the first lift lower limit H 下限1 , Second lift lower limit H 下限2 Make comparisons; If H 上限1 <H0<H 上限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is opened to enter PID tracking regulation; If H 上限2 <H0, the heat transfer oil circulation pump group is controlled to stop; If H 下限1 <H0<H 下限2 , an alarm message is generated, and the low flow regulating valve of the thermal oil circulation pump is closed; If H0<H 下限1 , then the thermal oil circulation pump group is controlled to shut down.

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