Gas storage pressure energy power generation system and grid-connected control method thereof

Abstract

The invention discloses a gas storage pressure energy power generation system and a grid-connected control method thereof, and relates to the technical field of new energy power generation. The system comprises m energy conversion units which are located in a gas storage gathering and injecting station and used for converting pressure energy in a gas storage into electric energy; the distributed electric energy grid-connected control unit is connected with the m energy conversion units, and adjusts and distributes electric energy according to the load requirement of the power grid; and the electric energy quality management platform is respectively connected with the m energy conversion units and the distributed electric energy grid-connected control unit and is used for monitoring the electric energy quality in real time. The electric energy quality can be monitored in real time, and electric energy is intelligently distributed according to load requirements; and meanwhile, a load flow calculation model in a grid-connected control strategy can be automatically optimized, and the energy conversion efficiency is dynamically evaluated and analyzed, so that the stability and controllability of output electric energy are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of renewable energy power generation, and in particular to a gas storage pressure energy power generation system and a grid-connected control method thereof. Background Art

[0002] In recent years, my country has made significant progress in the construction of gas storage facilities. Currently, more than 50 gas storage facilities of various types have been put into operation. The injection and production wells of these gas storage facilities are subject to gas storage pressures of up to tens of megapascals. During the gas production process, the high-pressure natural gas in the wellbore must be depressurized before it can be transported to various natural gas pipelines. However, the pressure energy released during the depressurization process is often not effectively utilized. If this pressure energy can be used for power generation, it can not only achieve the recycling of resources, but also significantly improve energy efficiency and help reduce carbon emissions. In addition, given that the gas pressure in the injection and production wells and the gas pipeline network remains relatively stable, the amount of electricity generated by this new power generation method is predictable and less volatile, which is conducive to the safe and stable operation of the power system.

[0003] Although there have been examples of applying pressure energy power generation systems to gas storage operations, as shown in the Chinese patent application with publication number 202310763818.8, current technical means are unable to calculate the energy conversion efficiency in the power generation process in real time, nor can they achieve online evaluation and optimization of power quality. Therefore, there are still certain challenges in ensuring that the electricity output by the pressure energy power generation system is safely and effectively integrated into the power grid. Summary of the invention

[0004] The purpose of the present invention is to propose a gas storage pressure energy power generation system and a grid-connected control method thereof, which can inject electric energy according to the load demand of the power grid, quantify the conversion efficiency of pressure energy and electric energy, and improve the stability and controllability of the output electric energy.

[0005] According to a first aspect of an embodiment of the present disclosure, a gas storage pressure energy power generation system is provided, comprising:

[0006] m energy conversion units, located in the gas storage collection and injection station, used to convert the pressure energy in the gas storage into electrical energy;

[0007] A distributed power grid-connected control unit is connected to the m energy conversion units and regulates and distributes power according to the load demand of the power grid;

[0008] The power quality management platform is connected to m energy conversion units and distributed power grid-connected control units respectively, and is used to monitor the power quality in real time.

[0009] In one embodiment, the gas production ends of one or more gas storage injection and production wells with close geographical locations are connected to the common gas production end of the gas storage injection and production station, and the output end of the gas storage injection and production station is connected to the corresponding energy conversion unit.

[0010] In one embodiment, the energy conversion unit includes a gas purification device, the dry gas output end of the device is connected to the pressurization system interface and the input end of the inlet pressure-stabilizing valve via an inlet pressure gauge, the output end of the inlet pressure-stabilizing valve is connected to one end of the gas flow meter via an inlet thermometer, the other end of the gas flow meter is connected to the input end of the expander, the screw of the expander is connected to the input end of the speed regulator, the output end of the speed regulator is connected to the screw of the generator, the output end of the generator is connected to the input end of the electric energy meter via the primary side of the current transformer, and the secondary side of the current transformer is connected to the input end of the parameter measuring instrument; the output end of the expander is connected to the input end of the outlet pressure-stabilizing valve, the output end of the outlet pressure-stabilizing valve is connected to one end of the outlet pressure gauge via an outlet thermometer, the other end of the outlet pressure gauge is connected to the input end of the gas pipeline through a gas valve, and the other end of the outlet pressure gauge is also connected to the pressurization system interface and the pressure reduction system interface.

[0011] In one embodiment, the gas purification device includes a pre-separator, the output end of the pre-separator is connected to the input end of the production separator via a precooler, the output end of the production separator is connected to the wet gas input end of the heat exchanger, the wet gas output end of the heat exchanger is connected to the input end of the low-temperature separator through a wet gas digital thermometer, the wet gas digital thermometer is used to display the temperature of the wet gas, the output end of the low-temperature separator is connected to the dry gas input end of the heat exchanger, the dry gas output end of the heat exchanger is connected to a dry gas digital thermometer, and the dry gas digital thermometer is used to display the temperature of the dry gas.

[0012] In one embodiment, the power quality management platform includes a platform computer, one end of the platform computer is connected to one end of the CAN bus via a CAN adapter card, and the other end of the CAN bus is connected to the signal end of the parameter measuring instrument in the energy conversion unit through a data acquisition card; the platform computer is connected to the control end of the reactive compensation device through a reactive compensation controller, and the output end of the reactive compensation device is connected to the reactive compensation interface of the distributed power grid-connected control unit; the platform computer is connected to the power meter through an RS485 communication bus; and the platform computer transmits data with the grid-connected computer of the distributed power grid-connected control unit through wireless communication.

[0013] In one embodiment, the distributed power grid-connected control unit includes m filters, the output end of each filter is connected to a reactive compensation interface and a low-voltage load interface, the filter is connected to one end of the circuit breaker through a connecting box transformer and a load-side disconnector, and the other end of the circuit breaker is connected to the collector bus through a bus-side disconnector; the collector bus is connected to a 35kV bus through a step-up transformer, the 35kV bus is connected to a 35kV load interface, and the 35kV bus is connected to a main circuit breaker through a line-side disconnector; the main circuit breaker is connected to a total electric energy meter through a grid-side disconnector, and the total electric energy meter is connected to a battery interface and a grid through a grid-connected point reactive compensation interface; the 35kV bus is also connected to a voltage transformer through a protective disconnector and a fuse; the control end of the line-side disconnector, the control end of the grid-side disconnector, the control end of the main circuit breaker, the signal end of the total electric energy meter, and the control end of the protective disconnector are all connected to a grid-connected computer through a hub, and the grid-connected computer transmits data with a platform computer of a power quality management platform through wireless communication.

[0014] In one embodiment, the inlet pressure gauge is connected to the grid-connected computer of the distributed power grid-connected control unit via a wireless signal, the signal end of the inlet thermometer is connected to the hub of the distributed power grid-connected control unit, and the signal end of the gas flow meter is connected to the hub of the distributed power grid-connected control unit; the output end of the power meter is connected to the input end of the filter in the distributed power grid-connected control unit, the signal end of the power meter is connected to the RS485 communication bus of the power quality management platform, and the signal end of the parameter measuring instrument is connected to the data acquisition card of the power quality management platform; the outlet pressure gauge is connected to the grid-connected computer of the distributed power grid-connected control unit via a wireless signal.

[0015] According to a second aspect of the embodiment of the present disclosure, the pressure energy of high-pressure natural gas produced by the injection and production wells of the gas storage reservoir is converted into electrical energy by using the above-mentioned gas storage reservoir pressure energy power generation system. According to the peak load demand of the power grid, the electrical energy is safely and reliably connected to the power grid through the grid connection control method, and at the same time, low-pressure gas that meets the gas transmission requirements is delivered to each natural gas transmission pipeline, including:

[0016] Setting the pre-generation state of the gas storage pressure energy generation system;

[0017] Start the switches and equipment of the gas storage reservoir pressure energy power generation system;

[0018] Monitor power quality in real time and perform grid connection control according to load demand;

[0019] After completing the power supply, turn off the switches and equipment of the gas storage pressure energy power generation system.

[0020] In one embodiment, the pre-power generation state of the gas storage pressure energy power generation system is set as follows:

[0021] Initialize the equipment status, that is, each load-side isolating switch, circuit breaker, and bus-side isolating switch are in the disconnected state, the protection isolating switch, line-side isolating switch, main circuit breaker, and grid-side isolating switch are in the disconnected state, and the metering data of each electric energy meter is cleared;

[0022] According to the gas production plan of the gas storage, the injection and production wells to be produced and the corresponding gas production time range are determined, which are represented by the set [tt1tt2], [tt2 tt3]...;

[0023] Find the union of the sets [tt1 tt2], [tt2 tt3], etc., using [tt0 tt n ]express;

[0024] The injection and production wells to be produced are named as "injection and production stations capable of generating electricity";

[0025] In the distributed power grid-connected control unit, the switchgear connected to the "power generation and injection station" is searched, including the load-side disconnector, circuit breaker and bus-side disconnector, and their labels are stored in the column vectors K, M and N in ascending order, that is, the first row elements of the column vectors K, M and N are all minimum values, and the last row elements are all maximum values.

[0026] In one embodiment, the switch and equipment of the gas storage reservoir pressure energy power generation system are started in the following manner:

[0027] Control the protective isolating switch to be in closed state;

[0028] Close all bus-side disconnectors corresponding to the elements in the vector N;

[0029] Close all load-side disconnectors corresponding to the elements in the vector K;

[0030] Close all circuit breakers corresponding to the elements in the vector M;

[0031] Start the data acquisition card connected to the "power generation and injection station" in the power quality management platform, and the reactive power controller and reactive power compensation device start working;

[0032] The energy conversion unit in the "power generation and injection station" is started, and the injection and production wells to be used for gas production begin to produce gas.

[0033] In one embodiment, the power quality is monitored in real time and grid connection control is performed according to load demand, specifically in the following manner:

[0034] Step 3.1: Store the labels of the “power generating collecting and injection stations” into the column vector W, where the first row of elements of the column vector W are all minimum values, and the last row of elements are all maximum values;

[0035] Step 3.2: Let Δt be the unit interval time, in h; t be the gas sampling time, in h; b be the number of calculations, with an initial value of 1; δ be the delay time, in h;

[0036] Step 3.3: t = tt0 + bΔt;

[0037] Step 3.4: Let i be the loop variable, and its initial value is 1;

[0038] Step 3.5: Let k be the index of the “power generating station”, and the value of k be the element of the i-th row in the column vector W;

[0039] Step 3.6: The inlet pressure gauge monitors the natural gas pressure flowing into the energy conversion unit k and converts the value P k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0040] Step 3.7: If P k (t) = 0, indicating that there is no gas inflow, proceed to step 3.17; if P k (t)>0, proceed to step 3.8; if P k (t)<0, output fault signal;

[0041] Step 3.8: If P k (t) If the gas pressure is lower than the minimum value required by the gas pipeline, an alarm signal is issued, the natural gas is transported to the pressurization system of the gathering and injection station through the pressurization system interface, and the corresponding energy conversion unit is shut down; if P k (t) When the gas pressure exceeds the minimum value required by the gas pipeline, the high-pressure gas pressure regulating valve opens, and the expander and generator work to convert the pressure energy into electrical energy;

[0042] Step 3.9: The outlet pressure gauge monitors the pressure of the natural gas flowing out of the energy conversion unit and converts the value PP k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0043] Step 3.10: If PP k (t) Within the gas transmission pressure range required by the gas pipeline, the gas valve opens to deliver natural gas to the gas pipeline. k (t) If the gas transmission pressure is lower than the minimum value, an alarm signal is issued and the natural gas is transported to the pressurization system of the filling station through the pressurization system interface. k (t) If the pressure is higher than the maximum value of the gas transmission pressure, an alarm signal is issued and the natural gas is transported to the pressure reduction system of the gathering and injection station through the pressure reduction system interface;

[0044] Step 3.11: The inlet thermometer monitors the temperature of the natural gas flowing into the energy conversion unit and converts the value T k (t) is transmitted to the grid-connected computer of the distributed power grid-connected control unit; the outlet thermometer monitors the temperature of the natural gas flowing out of the energy conversion unit and converts the value TT k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0045] Step 3.12: The gas flow meter monitors the cumulative flow of natural gas flowing into the expander k and converts the value G k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0046] Step 3.13: Monitor the power quality of generator k in real time;

[0047] Step 3.14: Obtain the energy conversion efficiency of generator k;

[0048] Step 3.15: If k is not the last row of the column vector W, set i=i+1 and repeat steps 3.5 to 3.14; if k is the last row of the column vector W, end the loop and proceed to step 3.16;

[0049] Step 3.16: Control the grid-connected power;

[0050] Step 3.17: If t<tt n , let b = b + 1, repeat steps 3.3 to 3.16, if t ≥ tt n , end the loop and proceed to step 3.18;

[0051] Step 3.18: Take all the elements of the kth column vector in the column vector group Y and plot the energy conversion efficiency η with time t as the horizontal axis. k (t) is the curve f on the vertical axis k (t).

[0052] In one embodiment, the power quality of the generator k is monitored in real time, specifically in the following manner:

[0053] The parameter measuring instrument transmits the parameters of the generator k output at time t to the power quality management platform through the signal terminal, including: voltage U k (t), current I k (t), power factor Three-phase voltage unbalance Q k (t);

[0054] According to the parameters at time t, the voltage deviation percentage U output by generator k is obtained k (t)%, as shown in Formula 1:

[0055]

[0056] Among them, U k (t) is the actual voltage of the generator measured by the parameter measuring instrument, in V; U N is the rated voltage of the generator, in V;

[0057] The voltage is shifted by a percentage U k (t)% is stored in the bth row of the kth column vector in the column vector group X, where the vector group X is as shown in formula (2):

[0058]

[0059] If |U k (t)% | less than the allowable deviation value, proceed to the next step to determine Q k (t) is less than the allowable deviation value; if |U k (t)% | is not less than the allowable deviation value, then the output is "voltage deviation is unqualified". According to the power flow calculation model, the capacity required for reactive power compensation is determined, and the compensation capacity is applied to the distributed power grid-connected control unit through the reactive power compensation interface k of the power quality management platform to reduce |U k (t)%|value;

[0060] If Q k (t) is less than the allowable deviation value, then return to the previous step to judge |U k (t) % | Is it less than the allowable deviation value? k (t) is not less than the allowable deviation value, and outputs "three-phase unbalance is unqualified". According to the power flow calculation model, the unbalanced load that needs to be reduced is determined, and the unbalanced load is removed from the distributed power grid-connected control unit through the low-voltage load interface k.

[0061] In one embodiment, the energy conversion efficiency of the generator k is obtained by:

[0062] According to natural gas The pressure energy flowing into the expander k is obtained theoretically as shown in formula (3);

[0063]

[0064] Among them, E k (t) is the pressure energy generated by each kilogram of natural gas in the “power-generating collecting and injecting station” k at time t, in kJ / kg; C p is the isobaric specific heat capacity of natural gas, in kJ / (kg·K); M is the molar mass of natural gas, in kg / kmol; R is the molar gas constant of natural gas, in kJ / (kmol·K); Tk (t) is the natural gas input temperature at time t, measured by the inlet thermometer of the energy conversion unit; TT k (t+δ) is the natural gas output temperature at time t+δ, measured by the outlet thermometer of the energy conversion unit, P i (t) is the natural gas input pressure at time t, measured by the inlet pressure gauge of the energy conversion unit, PP k (t+δ) is the natural gas output pressure at time t+δ, measured by the outlet pressure gauge of the energy conversion unit, and T0 is the ambient temperature;

[0065] The pressure energy E k (t) Store in the b-th row of the k-th column vector in the column vector set V;

[0066] Obtaining energy conversion efficiency η k (t), and store it in the bth row of the kth column vector in the vector group Y, η k The method of obtaining (t) is shown in formula (4):

[0067]

[0068] Among them, W k (t) is the cumulative power generation of generator i during time t, in kWh, W k (t-Δt) is the cumulative power generation of generator k during the time (t-Δt), in kWh, W k (t) and W k (t-Δt) is measured by the electric energy meter k; ρ is the density of natural gas, the unit is kg / m 3 , G k (t-Δt) is the cumulative natural gas flow rate flowing into expander k during the time (t-Δt), in m 3 , G k (t) and G k (t-Δt) is transmitted from the control end of the gas flow meter to the grid-connected computer via the hub.

[0069] In one embodiment, the grid-connected power is controlled in the following manner:

[0070] The grid-connected computer based on the distributed power grid-connected control unit calculates the load of each low-voltage load interface at time t, and the results are expressed as P1+jQ1, P1+jQ2, ... P m +jQ m express;

[0071] Determine whether the active power generated by each generator meets the low-voltage load requirements and obtain the remaining active power;

[0072] Determine whether the reactive power generated by each generator meets the low-voltage load requirements and obtain the remaining reactive power;

[0073] Output total remaining active power A=A1+A2+……+A z +……;

[0074] Output total residual reactive power B = B1 + B2 + ... + B z +……;

[0075] If A=0 and B>0, perform the step of calculating the reactive power of power supply at the 10kV calculation point at time t; if A>0 and B=0, perform the step of calculating the active power of power supply at the 10kV calculation point at time t; if A>0 and B>0, perform the step of calculating the power supply power at the 10kV calculation point at time t; if A=0 and B=0, output "this power generation system cannot provide active power and reactive power to all 10kV loads, all 35kV loads and grid connection points", and then judge whether t is less than tt n Steps;

[0076] According to the power flow calculation model and B, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the reactive power of the power supply at the 10kV calculation point at time t, and the result is D. At the same time, the power supply active power C≤0, and then the step of judging the relationship between the 10kV power supply active power C and the 10kV active load E is performed;

[0077] According to the power flow calculation model and A, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply active power at the 10kV calculation point at time t, and the result is C. At the same time, the power supply reactive power D≤0, and then the step of judging the relationship between the 10kV power supply active power C and the 10kV active load E is performed;

[0078] According to the power flow calculation model and A+jB, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply power at the 10kV calculation point at time t, and the result obtained is C+jD, and then the step of determining the relationship between the 10kV power supply active power C and the 10kV active load E is performed;

[0079] If C≥E, output 10kV residual active power H=CE; if C<E and C≤0, output 10kV residual active power H=0, prompting the staff that it is impossible to provide active power to all 10kV loads, all 35kV loads and grid connection points; if C<E and C>0, output 10kV residual active power H=0, prompting the staff that it is impossible to provide active power to some 10kV loads, all 35kV loads and grid connection points;

[0080] Determine the relationship between the 10kV power supply reactive power D and the 10kV reactive load F: if D≥F, output 10kV residual reactive power L=DF; if D<F and D≤0, output 10kV residual reactive power L=0, prompting the staff that it is impossible to provide reactive power to all 10kV loads, all 35kV loads and grid connection points; if D<F and D>0, output 10kV residual reactive power L=0, prompting the staff that it is impossible to provide reactive power to some 10kV loads, all 35kV loads and grid connection points;

[0081] According to the power flow calculation model and H+jL, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply at the 35kV calculation point at time t, and the result is expressed as M+jN;

[0082] Determine the relationship between the 35kV power supply active power M and the 35kV active load R: if M≥R, output 35kV residual active power T=MR; if M<R and M≤0, output 35kV residual active power T=0, prompting the staff that it is impossible to provide active power to all 35kV loads and grid connection points; if M<R and M>0, output 35kV residual active power T=0, prompting the staff that it is impossible to provide active power to some 35kV loads and grid connection points;

[0083] Determine the relationship between the 35kV power supply reactive power N and the 35kV reactive load S: if N≥S, output 35kV residual reactive power W=NS; if N<S and N≤0, output 35kV residual reactive power W=0, prompting the staff that it is impossible to provide reactive power to all 35kV loads and grid connection points; if N<S and N>0, output 35kV residual reactive power W=0, prompting the staff that it is impossible to transmit reactive power to some 35kV loads and grid connection points;

[0084] According to the power flow calculation model and T+jW, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply of the grid-connected point at time t, and the result is expressed as X+jY;

[0085] The grid-connected power X at time t measured by the total electric energy meter c +jY c , and X+jY, based on the neural network algorithm, the power flow calculation model is corrected to improve the accuracy of the next calculation;

[0086] Judge X c , Y c Size: If X c >0 and Y c > 0, output "can simultaneously transmit active power and reactive power to the grid connection point"; if X c ≤0 and Y c≤0, output "unable to transmit active power and reactive power to the grid connection point"; if X c >0 and Y c ≤0, output "only active power can be transmitted to the grid connection point, but reactive power cannot be transmitted to the grid connection point"; if X c ≤0 and Y c >0, output "only reactive power can be transmitted to the grid connection point, but active power cannot be transmitted to the grid connection point";

[0087] According to the power supply demand of the power grid to which the grid connection point is connected, the active power and reactive power injected into the grid by the grid connection point are determined.

[0088] In one embodiment, it is determined whether the active power generated by each generator meets the low-voltage load requirement in the following manner:

[0089] Set the initial value of the loop variable z to 1;

[0090] If the active power output of generator z is P fz Greater than or equal to low voltage active load P z , indicating that generator z can satisfy P z The demand for outputting the remaining active power A z =P fz -P z ; If the active power P output by generator z fz Less than low voltage active load P z , indicating that the generator z cannot satisfy P z The demand, let A z =0, remind the staff to switch to the backup power supply;

[0091] If z is not an element in the last row of column vector W, set z=z+1 and repeat the above; if z is an element in the last row of column vector W, end the loop.

[0092] In one embodiment, it is determined whether the reactive power generated by each generator meets the low-voltage load requirement in the following manner:

[0093] Set the initial value of the loop variable z to 1;

[0094] If the reactive power Q generated by generator z is fz Greater than or equal to low voltage reactive load Q z This shows that the generator z can satisfy Q z The demand for outputting the remaining reactive power B z =Q fz -Q z ; If the reactive power Q generated by generator z fz Less than low voltage reactive load Q z , indicating that the generator z cannot satisfy Q z demand, let Bz =0, remind the staff to switch to the backup power supply;

[0095] If z is not the element of the last row in the column vector W, let z=z+1 and repeat the above steps; if z is the element of the last row in the column vector W, end the loop.

[0096] In one embodiment, the active power and reactive power injected into the grid by the grid connection point are determined by:

[0097] Find the power demand at time t in the daily load curve of the power grid connected to the grid point, where the required active power and reactive power are represented by X and w , Y w ;

[0098] If X c ≤X w , the active power X c Inject into the grid; if X c >X w , X w Inject into the grid, and at the same time, the remaining active power X u =X c -X w Inject into the battery through the battery port;

[0099] If Y c ≤Y w , X c Injected into the grid; if Y c >Y w , Y w Inject it into the grid, and at the same time, the reactive power compensation device of the power quality management platform will compensate the residual reactive power Y u =Y c -Y w Perform reactive power compensation.

[0100] In one embodiment, the switches and equipment of the gas storage reservoir pressure energy power generation system are turned off by:

[0101] Shut down the energy conversion unit in the "Energy-generating Collection and Injection Station";

[0102] The data acquisition card connected to the "power generation and injection station" in the power quality management platform stops collecting data, and the reactive power controller and reactive power compensation device stop working;

[0103] Disconnect all circuit breakers corresponding to the elements in vector M;

[0104] Disconnect all load-side disconnectors corresponding to the elements in vector K;

[0105] Disconnect all bus-side disconnectors corresponding to the elements in vector N.

[0106] Compared with the prior art, the above technical solution adopted by the present invention has the following advantages:

[0107] The present invention can monitor the power quality in real time and intelligently distribute power according to load demand; at the same time, it can also automatically optimize the power flow calculation model in the grid-connected control strategy and dynamically evaluate and analyze the energy conversion efficiency, thereby significantly improving the stability and controllability of the output power.

[0108] In addition, the present invention not only promotes the recycling of energy, improves energy efficiency, and effectively reduces carbon emissions, but also can accurately respond to the load demand of the power grid and flexibly inject electric energy. It can also quantitatively analyze the conversion efficiency between pressure energy and electric energy, ensuring the quality of electric energy while effectively saving investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0110] Figure 1 This is the principle diagram of the gas storage pressure energy power generation system;

[0111] Figure 2 It is the schematic diagram of the energy conversion unit;

[0112] Figure 3 It is the schematic diagram of the distributed power grid-connected control unit;

[0113] Figure 4 This is the schematic diagram of the power quality management platform;

[0114] Figure 5 This is the schematic diagram of the gas purification device. DETAILED DESCRIPTION

[0115] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0116] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0117] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0118] Example 1

[0119] like Figure 1 As shown, this embodiment provides a gas storage reservoir pressure energy power generation system including m energy conversion units, a distributed power grid-connected control unit, and a power quality management platform, wherein m is a positive integer greater than or equal to 1;

[0120] like Figure 2 As shown, the energy conversion unit includes a gas purification device, an inlet pressure gauge, an outlet pressure gauge, an inlet pressure regulating valve, an outlet pressure regulating valve, a gas valve, a gas flow meter, an inlet thermometer, an outlet thermometer, an expander, a speed regulator, a generator, a current transformer, a parameter measuring instrument, and an electric energy meter. The inlet pressure gauge is used to measure the pressure of the gas outflowing from the gas purification device, and transmits it to the grid-connected computer of the distributed power grid-connected control unit through wireless communication, and at the same time, the relationship between the pressure and the inlet pressure of the expander is determined. If the pressure is less than the minimum inlet pressure required by the expander, the gas needs to be pressurized by the pressurization system. If the pressure is greater than or equal to the minimum inlet pressure required by the expander, the gas is delivered to the expander through the inlet pressure-stabilizing valve; the outlet pressure gauge is used to measure the pressure of the outlet pressure-stabilizing valve, and transmits it to the grid-connected computer of the distributed power grid-connected control unit through wireless communication, and at the same time, the relationship between the pressure and the input pressure of the gas pipeline is determined. If the pressure is less than the minimum value of the input pressure of the gas pipeline, the gas needs to be pressurized by the pressurization system and then output to the gas pipeline. If the pressure is greater than the maximum value of the input pressure of the gas pipeline, the gas needs to be depressurized by the depressurization system and then output to the gas pipeline; in this embodiment, the model of the inlet pressure gauge and the outlet pressure gauge is preferably MD-S270, with a range of 0 to 100 MPa, and the model of the inlet pressure-stabilizing valve and the outlet pressure-stabilizing valve is preferably ZZYP-16C;

[0121] The inlet thermometer is used to measure the temperature of the gas flowing into the expander, and transmits it to the grid-connected computer of the distributed power grid-connected control unit through the RS485 communication bus; the outlet thermometer is used to measure the temperature of the gas flowing out of the outlet pressure regulating valve, and transmits it to the grid-connected computer of the distributed power grid-connected control unit through the RS485 communication bus; the gas flowmeter is used to measure the gas flow rate flowing into the expander, and transmits it to the grid-connected computer of the distributed power grid-connected control unit through the RS485 communication bus; the electric energy meter is used to measure the amount of electricity output by the generator, and the gas valve is used to control the gas flow rate flowing into the gas pipeline; in this embodiment, the models of the inlet thermometer and the outlet thermometer are preferably JK-FB001WS, the model of the electric energy meter is preferably DTSD341, and the model of the gas flowmeter is preferably LWQ-DN100;

[0122] The expander is a screw expander, which is used to convert pressure energy into mechanical energy on the screw, and the speed regulator is used to adjust the speed of the expander screw; the generator is a permanent magnet synchronous generator, which outputs 0.4kV AC; the current transformer is used to reduce the output current of the generator to a small current within the measurement range of the parameter measuring instrument according to the transformation ratio, and the current transformer can also protect the parameter measuring instrument; the parameter measuring instrument is used to measure the voltage, current, power factor and three-phase voltage imbalance output by the generator, and transmit the parameters to the power quality management platform through the signal terminal; in this embodiment, the current transformer model is preferably LMZJ1, and the parameter measuring instrument model is preferably YP9830;

[0123] like Figure 3 As shown, the distributed electric energy grid-connected control unit includes a grid-connected computer, a concentrator, a box-type transformer, a collector bus, a filter, a 35kV bus, a main circuit breaker, a grid-side disconnector, a line-side disconnector, a load-side disconnector, a bus-side disconnector, a protective disconnector, a circuit breaker, a fuse, a voltage transformer, a total electric energy meter, and a step-up transformer;

[0124] The grid-connected computer is used to store the metering results of the total electric energy meter, as well as the gas flow, inlet temperature, outlet temperature, inlet pressure, and outlet pressure of multiple energy conversion units, and is used to issue control instructions for load-side disconnectors, bus-side disconnectors, and circuit breakers, and is used to issue control instructions for line-side disconnectors, main circuit breakers, grid-side disconnectors, and protection disconnectors, and is used for load calculation and power flow calculation; the hub is used to collect signal lines of the total electric energy meter, gas flow meter, inlet thermometer, and outlet thermometer, and is used to collect control lines of load-side disconnectors, bus-side disconnectors, circuit breakers, line-side disconnectors, main circuit breakers, grid-side disconnectors, and protection disconnectors; in this embodiment, the preferred model of the grid-connected computer is RTX4090, and the preferred model of the hub is JT-4MFL, which can allow access to 256 RS485 communication lines;

[0125] The box-type transformer increases the 0.4kV voltage output by the generator to 10kV, with a transformation ratio of 0.4kV / 10kV. The collector bus is used to collect the electric energy output by multiple energy conversion units, with a voltage level of 10kV. The filter is used to filter the high-order harmonics in the line. The load-side disconnector, the bus-side disconnector, and the circuit breaker are used to control the on-off of the output current of each energy conversion unit; the step-up transformer increases the 10kV voltage output by the collector bus to 35kV, with a transformation ratio of 10kV / 35kV; the 35kV bus is used to collect the 35kV electric energy output by the step-up transformer, the line-side disconnector, the main circuit breaker, and the grid-side disconnector are used to control the on-off of the current of the grid-connected point connected to the grid, and the total electric energy meter is used to measure the amount of electricity connected to the grid at the grid-connected point; the protection disconnector is used Control whether the voltage transformer is connected to the 35kV bus. The fuse is used to prevent the voltage transformer and its lead-out line from failing and affecting the high-voltage system. The voltage transformer is used to measure the 35kV bus voltage to prevent overvoltage. In this embodiment, the filter model is XNAPF, and the harmonic range that can be filtered is 2 to 50 times. The circuit breaker model is ZW32, with a rated voltage of 10kV. The main circuit breaker model is ZW7, with a rated voltage of 35kV. The load-side disconnector and the bus-side disconnector are both GN19-10. The preferred models of the protection disconnector, the line-side disconnector, and the grid-side disconnector are GW5-35. The preferred model of the total electric energy meter is DTSD341. The preferred model of the voltage transformer is JDZX9-35, and the preferred model of the fuse is HRW12-35.

[0126] like Figure 4 As shown, the power quality management platform includes a platform computer, a CAN adapter card, a CAN bus, a data acquisition card, a reactive power compensation controller, a reactive power compensation device, and an RS485 communication bus;

[0127] The platform computer is used to store the output power and voltage, current, power factor, and three-phase voltage imbalance of each energy conversion unit, and is used to issue control instructions for compensation capacity; the reactive compensation controller controls the reactive compensation device to output the required compensation capacity, and the reactive compensation device is used to perform reactive compensation on the low-voltage side of the box-type transformer and the grid connection point to ensure the quality of electric energy; the preferred model of the CAN bus is BT1207, and the CAN adapter card is used to convert the CAN interface into a USB interface, and the preferred model is CANalyst-Ⅱ; the preferred model of the RS485 communication bus is ADM-2542, and the data acquisition card is used to collect the signal measured by the parameter measuring instrument, and the preferred model is C-7017;

[0128] Example 2

[0129] like Figure 5As shown, this embodiment provides a gas purification device, including a pre-separator, a pre-cooler, a production separator, a heat exchanger, a wet gas digital thermometer, and a dry gas digital thermometer;

[0130] The pre-separator is used to complete the three-phase separation of oil, gas and water and measure them, and the pre-cooler is used to cool the natural gas to a specified temperature. In this embodiment, the specified temperature is 25°C; the production separator is used to complete the two-phase separation of gas and liquid, and the heat exchanger is used to cool the wet gas and heat the dry gas and condensate; the wet gas digital thermometer and the dry gas digital thermometer are used to measure the temperature of the wet gas and the dry gas respectively, and the preferred model is CYT521F, with a temperature measurement range of -200 to 600°C and an explosion-proof grade of EXdⅡCT6;

[0131] Example 3

[0132] The gas storage reservoir pressure energy power generation system described in Example 1 is used to convert the pressure energy of the high-pressure natural gas produced by the injection and production wells of the gas storage reservoir into electrical energy. According to the peak load demand of the power grid, the electrical energy is safely and reliably connected to the power grid through the grid connection control method, and at the same time, the low-pressure gas that meets the gas transmission requirements is delivered to each natural gas transmission pipeline, including:

[0133] Step 1: Setting the pre-power generation state of the gas storage pressure energy power generation system;

[0134] Step 1.1: Initialize the equipment status, that is, all load-side disconnectors, circuit breakers, and bus-side disconnectors are in the disconnected state, protection disconnectors, line-side disconnectors, main circuit breakers, and grid-side disconnectors are in the disconnected state, and the metering data of each electric energy meter is cleared;

[0135] Step 1.2: According to the gas production plan of the gas storage, determine the injection and production wells to be produced and the corresponding gas production time range, which are represented by the sets [tt1 tt2], [tt2 tt3], etc.;

[0136] Step 1.3: Find the union of the sets [tt1 tt2], [tt2 tt3], etc. in step 1.2, and use [tt0 tt n ]express;

[0137] Step 1.4: Name the gas collecting and injection station where the gas injection and production wells to be produced are located as "power generation collecting and injection station";

[0138] Step 1.5: Search the switchgear connected to the “power generation and injection station” in the distributed power grid-connected control unit, including the load-side disconnector, circuit breaker and bus-side disconnector, and store their labels in the order from small to large into column vectors K, M and N, that is, the first row elements of the column vectors K, M and N are all minimum values, and the last row elements are all maximum values;

[0139] Step 2: Start the switches and equipment of the gas storage reservoir pressure energy power generation system;

[0140] Step 2.1: Control the protective isolating switch to a closed state;

[0141] Step 2.2: Close all bus-side disconnectors corresponding to the elements in vector N;

[0142] Step 2.3: Close all load-side disconnectors corresponding to the elements in vector K;

[0143] Step 2.4: Close all circuit breakers corresponding to the elements in vector M;

[0144] Step 2.5: Start the data acquisition card connected to the "power generation and injection station" in the power quality management platform, and the reactive power controller and reactive power compensation device start working;

[0145] Step 2.6: Start the energy conversion unit in the "power generation station" and the injection and production wells to be produced start producing gas;

[0146] Step 3: Monitor power quality in real time and perform grid connection control according to load demand;

[0147] Step 3.1: Store the labels of the “power generating stations” into the column vector W, that is, the first row of elements of the column vector W are all minimum values, and the last row of elements are all maximum values;

[0148] Step 3.2: Let Δt be the unit interval time, in h; t be the gas sampling time, in h; b be the number of calculations, with an initial value of 1; δ be the delay time, in h;

[0149] Step 3.3: t = tt0 + bΔt;

[0150] Step 3.4: Let i be the loop variable, and its initial value is 1;

[0151] Step 3.5: Let k be the index of the “power generating station”, and the value of k be the element of the i-th row in the column vector W;

[0152] Step 3.6: The inlet pressure gauge monitors the natural gas pressure flowing into the energy conversion unit k and converts the value P k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0153] Step 3.7: Determine P k (t) is equal to 0: If P k (t) = 0, indicating that there is no gas inflow, proceed to step 3.17; if P k (t)>0, proceed to step 3.8; if P k (t)<0, output fault signal;

[0154] Step 3.8: Determine P k (t) Whether the gas pressure is lower than the minimum value required by the gas pipeline: If it is lower than the minimum value, an alarm signal is issued, the natural gas is transported to the pressurization system of the filling station through the pressurization system interface, and the corresponding energy conversion unit is closed; if it is higher than the minimum value, the high-pressure gas pressure regulating valve is opened, the expander and the generator are operated to convert the pressure energy into electrical energy;

[0155] Step 3.9: The outlet pressure gauge monitors the pressure of the natural gas flowing out of the energy conversion unit and converts the value PP k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0156] Step 3.10: Determine PP k (t) Whether the gas pressure is within the required gas transmission pressure range of the gas transmission pipeline: if it is within the range, the gas valve opens to deliver the natural gas to the gas transmission pipeline; if it is lower than the minimum gas transmission pressure, an alarm signal is issued to deliver the natural gas to the pressurization system of the gas collection station through the pressurization system interface; if it is higher than the maximum gas transmission pressure, an alarm signal is issued to deliver the natural gas to the pressure reduction system of the gas collection station through the pressure reduction system interface;

[0157] Step 3.11: The inlet thermometer monitors the temperature of the natural gas flowing into the energy conversion unit and converts the value T k (t) is transmitted to the grid-connected computer of the distributed power grid-connected control unit; the outlet thermometer monitors the temperature of the natural gas flowing out of the energy conversion unit and converts the value TT k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0158] Step 3.12: The gas flow meter monitors the cumulative flow of natural gas flowing into the expander k and converts the value G k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit;

[0159] Step 3.13: Monitor the power quality of generator k in real time;

[0160] Step 3.13.1: The parameter measuring instrument transmits the parameters of the generator k output at time t to the power quality management platform through the signal terminal, including: voltage U k (t), current I k (t), power factor Three-phase voltage unbalance Q k (t);

[0161] Step 3.13.2: Based on the parameters measured in step 3.13.1, obtain the voltage deviation percentage U output by generator k k (t)%, as shown in Formula 1:

[0162]

[0163] Among them, U k (t) is the actual voltage of the generator measured by the parameter measuring instrument, in V; U N is the rated voltage of the generator, in V;

[0164] Step 3.13.3: Substitute the U calculated in step 3.13.2 into k (t)% is stored in the bth row of the kth column vector in the column vector group X, where the vector group X is shown in formula (2):

[0165]

[0166] Step 3.13.4: Determine |U k (t)% | Is it less than the allowable deviation value: If it is less than the allowable deviation value, proceed to step 3.13.5; if it is not less than the allowable deviation value, output "voltage deviation is unqualified", determine the capacity required for reactive power compensation according to the power flow calculation model, and apply the compensation capacity to the distributed power grid-connected control unit through the reactive power compensation interface k of the power quality management platform to reduce |U k (t)%|value;

[0167] Step 3.13.5: Determine Q k (t) Is it less than the allowable deviation value: If it is less than the allowable deviation value, proceed to step 3.14; if it is not less than the allowable deviation value, output "three-phase unbalance is unqualified", determine the unbalanced load that needs to be reduced according to the power flow calculation model, and remove the unbalanced load from the distributed power grid-connected control unit through the low-voltage load interface k;

[0168] Step 3.14: Obtain the energy conversion efficiency of generator k;

[0169] Step 3.14.1: According to the natural gas The pressure energy flowing into the expander k is theoretically calculated as shown in formula (3);

[0170]

[0171] Among them, E k (t) is the pressure energy generated by each kilogram of natural gas in the “power-generating collecting and injecting station” k at time t, in kJ / kg; C p is the isobaric specific heat capacity of natural gas, in kJ / (kg·K); M is the molar mass of natural gas, in kg / kmol; R is the molar gas constant of natural gas, in kJ / (kmol·K); T k (t) is the natural gas input temperature at time t, measured by the inlet thermometer of the energy conversion unit; TTk (t+δ) is the natural gas output temperature at time t+δ, measured by the outlet thermometer of the energy conversion unit, P i (t) is the natural gas input pressure at time t, measured by the inlet pressure gauge of the energy conversion unit, PP k (t+δ) is the natural gas output pressure at time t+δ, measured by the outlet pressure gauge of the energy conversion unit, and T0 is the ambient temperature;

[0172] Step 3.14.2: Substitute the E calculated in step 3.14.1 into k (t) Store in the b-th row of the k-th column vector in the column vector set V;

[0173] Step 3.14.3: Obtain the energy conversion efficiency η k (t), and store it in the bth row of the kth column vector in the column vector group Y, η k The method of obtaining (t) is shown in formula (4):

[0174]

[0175] Among them, W k (t) is the cumulative power generation of generator i during time t, in kWh, W k (t-Δt) is the cumulative power generation of generator k during the time (t-Δt), in kWh, W k (t) and W k (t-Δt) is measured by the electric energy meter k; ρ is the density of natural gas, the unit is kg / m 3 , G k (t-Δt) is the cumulative natural gas flow rate flowing into expander k during the time (t-Δt), in m 3 , G k (t) and G k (t-Δt) is transmitted from the control end of the gas flow meter to the grid-connected computer via the hub;

[0176] Step 3.15: Determine whether k is the element of the last row in the column vector W: If not, set i=i+1 and repeat steps 3.5 to 3.14. If yes, end the loop and proceed to step 3.16;

[0177] Step 3.16: Control the grid-connected power;

[0178] Step 3.16.1: According to the load calculation method, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the load of each low-voltage load interface at time t, and the results are expressed as P1+jQ1, P1+jQ2, ... P m +jQ m表示 ;

[0179] Step 3.16.2: Determine whether the active power generated by each generator meets the low-voltage load requirements;

[0180] Step 3.16.2.1: Set the initial value of the loop variable z to 1;

[0181] Step 3.16.2.2: Determine the active power P output by generator z fz Is it greater than or equal to the low voltage active load P? z :If P fz ≥P z , indicating that generator z can satisfy P z The demand for outputting the remaining active power A z =P fz -P z If P fz <P z , indicating that the generator z cannot satisfy P z The demand, let A z =0, remind the staff to switch to the backup power supply;

[0182] Step 3.16.2.3: Determine whether z is the element in the last row of column vector W: If not, set z = z + 1 and repeat step 3.16.2.2; If so, end the loop;

[0183] Step 3.16.3: Determine whether the reactive power generated by each generator meets the low-voltage load requirements;

[0184] Step 3.16.3.1: Set the initial value of the loop variable z to 1;

[0185] Step 3.16.3.2: Determine the reactive power Q generated by generator z fz Is it greater than or equal to the low voltage reactive load Q? z :If Q fz ≥Q z , indicating that generator z can satisfy Q z The demand for outputting the remaining reactive power B z =Q fz -Q z If Q fz <Q z , indicating that the generator z cannot satisfy Q z demand, let B z =0, remind the staff to switch to the backup power supply;

[0186] Step 3.16.3.3: Determine whether z is the element in the last row of column vector W: If not, set z = z + 1 and repeat step 3.16.3.2; If so, end the loop;

[0187] Step 3.16.4: Output total remaining active power A = A1 + A2 + ... + A z +……;

[0188] Step 3.16.5: Output total residual reactive power B = B1 + B2 + ... + B z +……;

[0189] Step 3.16.6 determines whether A and B are 0: if A=0 and B>0, proceed to step 3.16.7; if A>0 and B=0, proceed to step 3.16.8; if A>0 and B>0, proceed to step 3.16.9; if A=0 and B=0, output "this power generation system cannot provide active power and reactive power to all 10kV loads, all 35kV loads and grid connection points", and then proceed to step 3.17;

[0190] Step 3.16.7: According to the power flow calculation model and B output in step 3.16.5, the computer of the distributed power grid-connected control unit is used to calculate the reactive power of the power supply at the 10kV calculation point at time t, and the result is D. At the same time, the active power supply C is set to ≤ 0, and then step 3.16.10 is performed;

[0191] Step 3.16.8: According to the power flow calculation model and A output in step 3.16.4, the computer of the distributed power grid-connected control unit is used to calculate the power supply active power at the 10kV calculation point at time t, and the result is C. At the same time, the power supply reactive power D is set to ≤ 0, and then step 3.16.10 is performed;

[0192] Step 3.16.9: According to the power flow calculation model and A+jB calculated in steps 3.16.4 and 3.16.5, the computer of the distributed power grid-connected control unit is used to calculate the power supply at the 10kV calculation point at time t, and the result is C+jD, and then step 3.16.10 is performed;

[0193] Step 3.16.10: Determine the relationship between the 10kV power supply active power C and the 10kV active load E? If C≥E, output 10kV residual active power H=CE; if C<E and C≤0, output 10kV residual active power H=0, prompting the staff that it is impossible to provide active power to all 10kV loads, all 35kV loads and grid connection points; if C<E and C>0, output 10kV residual active power H=0, prompting the staff that it is impossible to provide active power to some 10kV loads, all 35kV loads and grid connection points;

[0194] Step 3.16.11: Determine the relationship between the 10kV power supply reactive power D and the 10kV reactive load F? If D≥F, output 10kV residual reactive power L=DF; if D<F and D≤0, output 10kV residual reactive power L=0, prompting the staff that it is impossible to provide reactive power to all 10kV loads, all 35kV loads and grid connection points; if D<F and D>0, output 10kV residual reactive power L=0, prompting the staff that it is impossible to provide reactive power to some 10kV loads, all 35kV loads and grid connection points;

[0195] Step 3.16.12: Based on the power flow calculation model and H+jL calculated in steps 3.16.10 and 3.16.11, the computer of the distributed power grid-connected control unit is used to calculate the power supply at the 35kV calculation point at time t, and the result is expressed as M+jN;

[0196] Step 3.16.13: Determine the relationship between the 35kV power supply active power M and the 35kV active load R? If M≥R, output 35kV residual active power T=MR; if M<R and M≤0, output 35kV residual active power T=0, prompting the staff that it is impossible to provide active power to all 35kV loads and grid connection points; if M<R and M>0, output 35kV residual active power T=0, prompting the staff that it is impossible to provide active power to some 35kV loads and grid connection points;

[0197] Step 3.16.14: Determine the relationship between the 35kV power supply reactive power N and the 35kV reactive load S? If N≥S, output 35kV residual reactive power W=NS; if N<S and N≤0, output 35kV residual reactive power W=0, prompting the staff that it is impossible to provide reactive power to all 35kV loads and grid connection points; if N<S and N>0, output 35kV residual reactive power W=0, prompting the staff that it is impossible to supply reactive power to some 35kV loads and grid connection points;

[0198] Step 3.16.15: Based on the power flow calculation model and T+jW calculated in steps 3.16.13 and 3.16.14, the computer of the distributed power grid-connected control unit is used to calculate the power supply of the grid-connected point at time t, and the result is X+jY;

[0199] Step 3.16.16: Measure the grid-connected power X at time t from the total power meter c +jY c , and the calculation result X+jY of step 3.16.15, based on the neural network algorithm, the power flow calculation model adopted by the present invention is corrected to improve the accuracy of the next calculation;

[0200] Step 3.16.17: Determine Xc , Y c Size: If X c >0 and Y c > 0, output "can simultaneously transmit active power and reactive power to the grid connection point"; if X c ≤0 and Y c ≤0, output "unable to transmit active power and reactive power to the grid connection point"; if X c >0 and Y c ≤0, output "only active power can be transmitted to the grid connection point, but reactive power cannot be transmitted to the grid connection point"; if X c ≤0 and Y c >0, output "only reactive power can be transmitted to the grid connection point, but active power cannot be transmitted to the grid connection point";

[0201] Step 3.16.18: According to the power supply demand of the power grid to which the grid connection point is connected, determine the active power and reactive power injected into the grid by the grid connection point;

[0202] Step 3.16.18.1: Find the power demand at time t in the daily load curve of the power grid to which the grid connection point is connected, where the required active power and reactive power are represented by X and w , Y w ;

[0203] Step 3.16.18.2: Compare X c and X w Size: If X c ≤X w , the active power X c Inject into the grid; if X c >X w , X w Inject into the grid, and at the same time, the remaining active power X u =X c -X w Inject into the battery through the battery port;

[0204] Step 3.16.18.3: Compare Y c and Y w Size: If Y c ≤Y w , X c Injected into the grid; if Y c >Y w , Y w Inject it into the grid, and at the same time, the reactive power compensation device of the power quality management platform will compensate the residual reactive power Y u =Y c -Y w Perform reactive power compensation;

[0205] Step 3.17: Determine whether t is less than tt n :If t<tt n , let b = b + 1, repeat steps 3.3 to 3.16, if t ≥ tt n , end the loop and proceed to step 3.18;

[0206] Step 3.18: Take all the elements of the kth column vector in the column vector group Y and plot the energy conversion efficiency η with time t as the horizontal axis. k (t) is the curve f on the vertical axis k (t);

[0207] Step 4: Turn off the switches and equipment of the gas storage reservoir pressure energy power generation system;

[0208] Step 4.1: Turn off the energy conversion unit in the "power generation collection station";

[0209] Step 4.2: The data acquisition card connected to the "power generation and injection station" in the power quality management platform stops collecting data, and the reactive power controller and reactive power compensation device stop working;

[0210] Step 4.3: Disconnect all circuit breakers corresponding to the elements in vector M;

[0211] Step 4.4: Disconnect all load-side disconnectors corresponding to the elements in vector K;

[0212] Step 4.5: Disconnect all bus-side disconnectors corresponding to the elements in vector N.

[0213] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0214] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A gas storage pressure energy power generation system, characterized in that: include: m energy conversion units, located in the gas storage collection and injection station, used to convert the pressure energy in the gas storage into electrical energy; A distributed power grid-connected control unit is connected to the m energy conversion units and regulates and distributes power according to the load demand of the power grid; The power quality management platform is connected to m energy conversion units and distributed power grid-connected control units respectively, and is used to monitor the power quality in real time.

2. A gas storage pressure energy power generation system according to claim 1, characterized in that: The gas production ends of one or more gas storage injection and production wells with close geographical locations are connected in parallel to the common gas production end of the gas storage injection and production station, and the output end of the gas storage injection and production station is connected in parallel to the corresponding energy conversion unit.

3. A gas storage pressure energy power generation system according to claim 1, characterized in that: The energy conversion unit includes a gas purification device, the dry gas output end of the device is connected to the pressurization system interface and the input end of the inlet pressure-stabilizing valve via an inlet pressure gauge, the output end of the inlet pressure-stabilizing valve is connected to one end of the gas flow meter via an inlet thermometer, the other end of the gas flow meter is connected to the input end of the expander, the screw of the expander is connected to the input end of the speed regulator, the output end of the speed regulator is connected to the screw of the generator, the output end of the generator is connected to the input end of the electric energy meter via the primary side of the current transformer, and the secondary side of the current transformer is connected to the input end of the parameter measuring instrument; the output end of the expander is connected to the input end of the outlet pressure-stabilizing valve, the output end of the outlet pressure-stabilizing valve is connected to one end of the outlet pressure gauge via an outlet thermometer, the other end of the outlet pressure gauge is connected to the input end of the gas pipeline through a gas valve, and the other end of the outlet pressure gauge is also connected to the pressurization system interface and the pressure reduction system interface.

4. A gas storage pressure energy power generation system according to claim 3, characterized in that: The gas purification device includes a pre-separator, the output end of the pre-separator is connected to the input end of the production separator via a precooler, the output end of the production separator is connected to the wet gas input end of the heat exchanger, the wet gas output end of the heat exchanger is connected to the input end of the low-temperature separator via a wet gas digital thermometer, the wet gas digital thermometer is used to display the temperature of the wet gas, the output end of the low-temperature separator is connected to the dry gas input end of the heat exchanger, the dry gas output end of the heat exchanger is connected to a dry gas digital thermometer, and the dry gas digital thermometer is used to display the temperature of the dry gas.

5. A gas storage pressure energy power generation system according to claim 3, characterized in that: The power quality management platform includes a platform computer, one end of which is connected to one end of a CAN bus via a CAN adapter card, and the other end of the CAN bus is connected to the signal end of a parameter measuring instrument in an energy conversion unit via a data acquisition card; the platform computer is connected to the control end of a reactive compensation device via a reactive compensation controller, and the output end of the reactive compensation device is connected to a reactive compensation interface of a distributed power grid-connected control unit; the platform computer is connected to an electric energy meter via an RS485 communication bus; and the platform computer transmits data with a grid-connected computer of a distributed power grid-connected control unit via wireless communication.

6. A gas storage pressure energy power generation system according to claim 5, characterized in that: The distributed electric energy grid-connected control unit comprises m filters, the output end of each filter is connected with a reactive compensation interface and a low-voltage load interface, the filter is connected to one end of the circuit breaker through a connecting box transformer and a load-side disconnector, and the other end of the circuit breaker is connected to the collector bus through a bus-side disconnector; the collector bus is connected to a 35kV bus through a step-up transformer, the 35kV bus is connected with a 35kV load interface, and the 35kV bus is connected to a main circuit breaker through a line-side disconnector; the main circuit breaker is connected to a total electric energy meter through a grid-side disconnector, and the total electric energy meter is connected to a battery interface and a grid through a grid-connected point reactive compensation interface; the 35kV bus is also connected to a voltage transformer through a protective disconnector and a fuse; the control end of the line-side disconnector, the control end of the grid-side disconnector, the control end of the main circuit breaker, the signal end of the total electric energy meter, and the control end of the protective disconnector are all connected to a grid-connected computer through a hub, and the grid-connected computer transmits data with a platform computer of a power quality management platform through wireless communication.

7. A gas storage pressure energy power generation system according to claim 6, characterized in that: The inlet pressure gauge is connected to the grid-connected computer of the distributed power grid-connected control unit via a wireless signal, the signal end of the inlet thermometer is connected to the hub of the distributed power grid-connected control unit, and the signal end of the gas flow meter is connected to the hub of the distributed power grid-connected control unit; The output end of the electric energy meter is connected to the input end of the filter in the distributed electric energy grid-connected control unit, the signal end of the electric energy meter is connected to the RS485 communication bus of the power quality management platform, and the signal end of the parameter measuring instrument is connected to the data acquisition card of the power quality management platform; the outlet pressure gauge is connected to the grid-connected computer of the distributed electric energy grid-connected control unit via a wireless signal.

8. A grid-connected control method for a gas storage pressure energy power generation system, implemented based on the system according to any one of claims 1 to 7, characterized in that: include: Setting the pre-generation state of the gas storage pressure energy generation system; Start the switches and equipment of the gas storage reservoir pressure energy power generation system; Monitor power quality in real time and perform grid connection control according to load demand; After completing the power supply, turn off the switches and equipment of the gas storage pressure energy power generation system.

9. A grid-connected control method for a gas storage pressure energy power generation system according to claim 8, characterized in that: The pre-generation state of the gas storage pressure energy generation system is set as follows: Initialize the equipment status, that is, each load-side isolating switch, circuit breaker, and bus-side isolating switch are in the disconnected state, the protection isolating switch, line-side isolating switch, main circuit breaker, and grid-side isolating switch are in the disconnected state, and the metering data of each electric energy meter is cleared; According to the gas production plan of the gas storage, the injection and production wells to be produced and the corresponding gas production time range are determined, which are represented by the set [tt1 tt2], [tt2 tt3]...; Find the union of the sets [tt1 tt2], [tt2 tt3], etc., using [tt0 tt n ]express; The injection and production wells to be produced are named as "injection and production stations capable of generating electricity"; In the distributed power grid-connected control unit, the switchgear connected to the "power generation collection station" is searched, including the load-side disconnector, circuit breaker and bus-side disconnector, and their labels are stored in the column vectors K, M and N in ascending order, that is, the first row elements of the column vectors K, M and N are all minimum values, and the last row elements are all maximum values.

10. A grid-connected control method for a gas storage pressure energy power generation system according to claim 9, characterized in that: Start the switches and equipment of the gas storage reservoir pressure energy power generation system by: controlling the protective isolation switch to a closed state; Close all bus-side disconnectors corresponding to the elements in the vector N; Close all load-side disconnectors corresponding to the elements in the vector K; Close all circuit breakers corresponding to the elements in the vector M; Start the data acquisition card connected to the "power generation and injection station" in the power quality management platform, and the reactive power controller and reactive power compensation device start working; The energy conversion unit in the "power generation and injection station" is started, and the injection and production wells to be produced begin to produce gas.

11. A grid-connected control method for a gas storage pressure energy power generation system according to claim 9, characterized in that: Real-time monitoring of power quality and grid connection control based on load demand. The specific methods are as follows: Step 3.1: Store the labels of "power generating stations" into column vector W, where the first row of elements of column vector W are all minimum values ​​and the last row of elements are all maximum values; Step 3.2: Let Δt be the unit interval time, in h; t be the gas sampling time, in h; b be the number of calculations, with an initial value of 1; δ be the delay time, in h; Step 3.3: t = tt0 + bΔt; Step 3.4: Let i be the loop variable, and its initial value is 1; Step 3.5: Let k be the index of the "power generating station", and the value of k be the element of the i-th row in the column vector W; Step 3.6: The inlet pressure gauge monitors the natural gas pressure flowing into the energy conversion unit k and converts the value P k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.7: If P k (t) = 0, indicating that there is no gas inflow, proceed to step 3.17; if P k (t)>0, proceed to step 3.8; if P k (t)<0, output fault signal; Step 3.8: If P k (t) If the gas pressure is lower than the minimum value required by the gas pipeline, an alarm signal is issued, the natural gas is transported to the pressurization system of the gathering and injection station through the pressurization system interface, and the corresponding energy conversion unit is shut down; if P k (t) When the gas pressure exceeds the minimum value required by the gas pipeline, the high-pressure gas pressure regulating valve opens, and the expander and generator work to convert the pressure energy into electrical energy; Step 3.9: The outlet pressure gauge monitors the pressure of the natural gas flowing out of the energy conversion unit and converts the value PP k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.10: If PP k (t) Within the gas transmission pressure range required by the gas pipeline, the gas valve opens to transmit natural gas to the gas pipeline. k (t) If the gas transmission pressure is lower than the minimum value, an alarm signal is issued and the natural gas is transported to the pressurization system of the filling station through the pressurization system interface. k (t) If the pressure is higher than the maximum value of the gas transmission pressure, an alarm signal is issued and the natural gas is transported to the pressure reduction system of the gathering and injection station through the pressure reduction system interface; Step 3.11: The inlet thermometer monitors the temperature of the natural gas flowing into the energy conversion unit and converts the value T k (t) is transmitted to the grid-connected computer of the distributed power grid-connected control unit; the outlet thermometer monitors the temperature of the natural gas flowing out of the energy conversion unit and converts the value TT k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.12: The gas flow meter monitors the cumulative flow of natural gas flowing into the expander k and converts the value G k (t) transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.13: Monitor the power quality of generator k in real time; Step 3.14: Obtain the energy conversion efficiency of generator k; Step 3.15: If k is not the last row of the column vector W, set i=i+1 and repeat steps 3.5 to 3.14; if k is the last row of the column vector W, end the loop and proceed to step 3.16; Step 3.16: Control the grid-connected power; Step 3.17: If t<tt n , let b = b + 1, repeat steps 3.3 to 3.16, if t ≥ tt n , end the loop and proceed to step 3.18; Step 3.18: Take all the elements of the kth column vector in the column vector group Y and plot the energy conversion efficiency η with time t as the horizontal axis. k (t) is the curve f on the vertical axis k (t).

12. A grid-connected control method for a gas storage pressure energy power generation system according to claim 11, characterized in that: The power quality of generator k is monitored in real time, specifically in the following ways: The parameter measuring instrument transmits the parameters of the generator k output at time t to the power quality management platform through the signal terminal, including: voltage U k (t), current I k (t), power factor Three-phase voltage unbalance Q k (t); According to the parameters at time t, the voltage deviation percentage U output by generator k is obtained k (t)%, as shown in Formula 1: Among them, U k (t) is the actual voltage of the generator measured by the parameter measuring instrument, in V; U N is the rated voltage of the generator, in V; The voltage is shifted by a percentage U k (t)% is stored in the bth row of the kth column vector in the column vector group X, where the vector group X is as shown in formula (2): If |U k (t)% | less than the allowable deviation value, proceed to the next step to determine Q k (t) is less than the allowable deviation value; if |U k (t)% | is not less than the allowable deviation value, then the output is "voltage deviation unqualified". According to the power flow calculation model, the capacity required for reactive power compensation is determined, and the compensation capacity is applied to the distributed power grid-connected control unit through the reactive power compensation interface k of the power quality management platform to reduce |U k (t)%|value; If Q k (t) is less than the allowable deviation value, then return to the previous step to judge |U k (t) % | Is it less than the allowable deviation value? k (t) is not less than the allowable deviation value, and outputs "three-phase unbalance is unqualified". According to the power flow calculation model, the unbalanced load that needs to be reduced is determined, and the unbalanced load is removed from the distributed power grid-connected control unit through the low-voltage load interface k.

13. The grid-connected control method of a gas storage pressure energy power generation system according to claim 11, characterized in that: The energy conversion efficiency of generator k is obtained as follows: According to natural gas The pressure energy flowing into the expander k is obtained theoretically as shown in formula (3); Among them, E k (t) is the pressure energy generated by each kilogram of natural gas in the "power-generating collecting and injecting station" k at time t, in kJ / kg; C p is the mass isobaric specific heat capacity of natural gas, in kJ / (kg·K); M is the molar mass of natural gas, in kg / kmol; R is the molar gas constant of natural gas, in kJ / (kmol·K); T k (t) is the natural gas input temperature at time t, measured by the inlet thermometer of the energy conversion unit; TT k (t+δ) is the natural gas output temperature at time t+δ, measured by the outlet thermometer of the energy conversion unit, P i (t) is the natural gas input pressure at time t, measured by the inlet pressure gauge of the energy conversion unit, PP k (t+δ) is the natural gas output pressure at time t+δ, measured by the outlet pressure gauge of the energy conversion unit, and T0 is the ambient temperature; The pressure energy E k (t) Store in the b-th row of the k-th column vector in the column vector set V; Obtaining energy conversion efficiency η k (t), and store it in the bth row of the kth column vector in the vector group Y, η k The method of obtaining (t) is shown in formula (4): Among them, W k (t) is the cumulative power generation of generator i during time t, in kWh, W k (t-Δt) is the cumulative power generation of generator k during the time (t-Δt), in kWh, W k (t) and W k (t-Δt) is measured by the electric energy meter k; ρ is the density of natural gas, the unit is kg / m 3 , G k (t-Δt) is the cumulative natural gas flow rate flowing into expander k during the time (t-Δt), in m 3 , G k (t) and G k (t-Δt) is transmitted from the control end of the gas flow meter to the grid-connected computer via the hub.

14. A grid-connected control method for a gas storage pressure energy power generation system according to claim 11, characterized in that: The grid-connected power is controlled in the following ways: The grid-connected computer based on the distributed power grid-connected control unit calculates the load of each low-voltage load interface at time t, and the results are expressed as P1+jQ1, P1+jQ2, ... P m +jQ m express; Determine whether the active power generated by each generator meets the low-voltage load requirements and obtain the remaining active power; Determine whether the reactive power generated by each generator meets the low-voltage load requirements and obtain the remaining reactive power; Output total remaining active power A=A1+A2+……+A z +……; Output total residual reactive power B = B1 + B2 + ... + B z +……; If A=0 and B>0, perform the step of calculating the reactive power of power supply at the 10kV calculation point at time t; if A>0 and B=0, perform the step of calculating the active power of power supply at the 10kV calculation point at time t; if A>0 and B>0, perform the step of calculating the power supply power at the 10kV calculation point at time t; if A=0 and B=0, output "This power generation system cannot provide active power and reactive power to all 10kV loads, all 35kV loads and grid connection points", and then judge whether t is less than tt n Steps; According to the power flow calculation model and B, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the reactive power of the power supply at the 10kV calculation point at time t, and the result is D. At the same time, the power supply active power C≤0, and then the step of judging the relationship between the 10kV power supply active power C and the 10kV active load E is performed; According to the power flow calculation model and A, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply active power at the 10kV calculation point at time t, and the result is C. At the same time, the power supply reactive power D≤0, and then the step of judging the relationship between the 10kV power supply active power C and the 10kV active load E is performed; According to the power flow calculation model and A+jB, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply power at the 10kV calculation point at time t, and the result obtained is C+jD, and then the step of determining the relationship between the 10kV power supply active power C and the 10kV active load E is performed; If C≥E, output 10kV residual active power H=CE; if C<E and C≤0, output 10kV residual active power H=0, prompting the staff that it is impossible to provide active power to all 10kV loads, all 35kV loads and grid connection points; if C<E and C>0, output 10kV residual active power H=0, prompting the staff that it is impossible to provide active power to some 10kV loads, all 35kV loads and grid connection points; Determine the relationship between the 10kV power supply reactive power D and the 10kV reactive load F: if D≥F, output 10kV residual reactive power L=DF; if D<F and D≤0, output 10kV residual reactive power L=0, prompting the staff that it is impossible to provide reactive power to all 10kV loads, all 35kV loads and grid connection points; if D<F and D>0, output 10kV residual reactive power L=0, prompting the staff that it is impossible to provide reactive power to some 10kV loads, all 35kV loads and grid connection points; According to the power flow calculation model and H+jL, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply at the 35kV calculation point at time t, and the result is expressed as M+jN; Determine the relationship between the 35kV power supply active power M and the 35kV active load R: if M≥R, output 35kV residual active power T=MR; if M<R and M≤0, output 35kV residual active power T=0, prompting the staff that it is impossible to provide active power to all 35kV loads and grid connection points; if M<R and M>0, output 35kV residual active power T=0, prompting the staff that it is impossible to provide active power to some 35kV loads and grid connection points; Determine the relationship between the 35kV power supply reactive power N and the 35kV reactive load S: if N≥S, output 35kV residual reactive power W=NS; if N<S and N≤0, output 35kV residual reactive power W=0, prompting the staff that it is impossible to provide reactive power to all 35kV loads and grid connection points; if N<S and N>0, output 35kV residual reactive power W=0, prompting the staff that it is impossible to transmit reactive power to some 35kV loads and grid connection points; According to the power flow calculation model and T+jW, the grid-connected computer of the distributed power grid-connected control unit is used to calculate the power supply of the grid-connected point at time t, and the result is expressed as X+jY; The grid-connected power X at time t measured by the total electric energy meter c +jY c , and X+jY, based on the neural network algorithm, the power flow calculation model is corrected to improve the accuracy of the next calculation; Judge X c , Y c Size: If X c >0 and Y c > 0, the output "can simultaneously transmit active power and reactive power to the grid connection point"; if X c ≤0 and Y c ≤0, output "cannot transmit active power and reactive power to the grid connection point"; if X c >0 and Y c ≤0, the output "can only transmit active power to the grid connection point, and cannot transmit reactive power to the grid connection point"; if X c ≤0 and Y c >0, the output is "can only transmit reactive power to the grid connection point, and cannot transmit active power to the grid connection point"; According to the power supply demand of the power grid to which the grid connection point is connected, the active power and reactive power injected into the grid by the grid connection point are determined.

15. A grid-connected control method for a gas storage pressure energy power generation system according to claim 14, characterized in that: Determine whether the active power generated by each generator meets the low-voltage load requirements. The specific method is as follows: Set the initial value of the loop variable z to 1; If the active power output of generator z is P fz Greater than or equal to low voltage active load P z , indicating that generator z can satisfy P z The demand for outputting the remaining active power A z =P fz -P z ; If the active power P output by generator z fz Less than low voltage active load P z , indicating that the generator z cannot satisfy P z The demand, let A z =0, remind the staff to switch to the backup power supply; If z is not an element in the last row of column vector W, set z=z+1 and repeat the above; if z is an element in the last row of column vector W, end the loop.

16. A grid-connected control method for a gas storage pressure energy power generation system according to claim 14, characterized in that: Determine whether the reactive power generated by each generator meets the low-voltage load requirements. The specific method is as follows: Set the initial value of the loop variable z to 1; If the reactive power Q generated by generator z is fz Greater than or equal to low voltage reactive load Q z This shows that the generator z can satisfy Q z The demand for outputting the remaining reactive power B z =Q fz -Q z ; If the reactive power Q generated by generator z fz Less than low voltage reactive load Q z , indicating that the generator z cannot satisfy Q z demand, let B z =0, remind the staff to switch to the backup power supply; If z is not an element in the last row of column vector W, set z=z+1 and repeat the above steps; if z is an element in the last row of column vector W, end the loop.

17. A grid-connected control method for a gas storage pressure energy power generation system according to claim 14, characterized in that: Determine the active power and reactive power injected into the grid by the grid connection point, specifically: Find the power demand at time t in the daily load curve of the power grid connected to the grid point, where the required active power and reactive power are represented by X and w , Y w ; If X c ≤X w , the active power X c Inject into the grid; if X c >X w , X w Inject into the grid, and at the same time, the remaining active power X u =X c -X w Inject into the battery through the battery port; If Y c ≤Y w , X c Injected into the grid; if Y c >Y w , Y w Inject it into the grid, and at the same time, the reactive power compensation device of the power quality management platform will compensate the residual reactive power Y u =Y c -Y w Perform reactive power compensation.

18. The grid-connected control method of a gas storage pressure energy power generation system according to claim 8, characterized in that: Turn off the switches and equipment of the gas storage reservoir pressure energy power generation system by: turning off the energy conversion unit in the "power generation collection and injection station"; The data acquisition card connected to the "power generation and injection station" in the power quality management platform stops collecting data, and the reactive power controller and reactive power compensation device stop working; Disconnect all circuit breakers corresponding to the elements in vector M; Disconnect all load-side disconnectors corresponding to the elements in vector K; Disconnect all bus-side disconnectors corresponding to the elements in vector N.

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