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

Abstract

The application 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 injection station and are used for converting pressure energy in the gas storage into electric energy; a distributed electric energy grid-connected control unit is connected with the m energy conversion units and is used for adjusting and distributing electric energy according to load demand of a power grid; and an electric energy quality management platform is connected with the m energy conversion units and the distributed electric energy grid-connected control unit and is used for monitoring electric energy quality in real time. The application can monitor electric energy quality in real time, intelligently distribute electric energy according to load demand, can also automatically optimize a power flow calculation model in a grid-connected control strategy, dynamically evaluates and analyzes energy conversion efficiency, and thus significantly improves stability and controllability of output electric energy.

Description

TECHNICAL FIELD

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

[0002] In recent years, China's gas storage construction has made significant progress. Currently, more than 50 gas storages of various types have been put into operation. The injection and production wells of these gas storages bear a gas storage pressure as high as tens of megapascals. During the gas production process, the high-pressure natural gas in the wellbore needs to be depressurized before being transported to the natural gas pipeline. However, the pressure energy released during the depressurization process is often not effectively utilized. If this pressure energy can be used for power generation, not only can it achieve resource recycling, but it can 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 power generated by this new power generation method is predictable and has less fluctuation, which is beneficial 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, such as shown in Chinese Patent Application No. 202310763818.8, current technical means cannot 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, to ensure that the power output by the pressure energy power generation system is safely and effectively integrated into the power grid, there are still certain challenges. SUMMARY

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

[0005] According to a first aspect of the embodiments 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 cluster injection station, for converting pressure energy in the gas storage into power;

[0007] a distributed power grid-connected control unit connected to the m energy conversion units, for adjusting and distributing power according to the load demand of the power grid;

[0008] a power quality management platform connected to the m energy conversion units and the distributed power grid-connected control unit, for real-time monitoring of power quality.

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

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

[0011] In one of the embodiments, the gas purification device comprises a pre-separator, the output end of which is connected to the input end of a production separator through a pre-cooler, the output end of the production separator is connected to the wet gas input end of a heat exchanger, the wet gas output end of the heat exchanger is connected to the input end of a 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, and the dry gas output end of the heat exchanger is connected to a dry gas digital thermometer, which is used to display the temperature of the dry gas.

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

[0013] In one of the embodiments, the distributed power grid-connected control unit comprises m filters, the output end of each filter is connected with a reactive power compensation interface and a low-voltage load interface, the filter is connected to one end of a circuit breaker through a connection box-type transformer, a load-side disconnector, the other end of the circuit breaker is connected to a bus through a bus-side disconnector, the 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 power meter through a grid-side disconnector, the total power meter is connected to a battery interface and a power grid through a grid point reactive power compensation interface, the 35kV bus is further connected to a voltage transformer through a protection 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 power meter and the control end of the protection disconnector are connected to a grid-connected computer through a concentrator, and the grid-connected computer transmits data to a platform computer of a power quality management platform through wireless communication.

[0014] In one of the embodiments, the inlet pressure gauge is connected to the grid-connected computer of the distributed power grid-connected control unit through a wireless signal, the signal end of the inlet thermometer is connected to the concentrator of the distributed power grid-connected control unit, and the signal end of the gas flow meter is connected to the concentrator 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 an RS485 communication bus of the power quality management platform, and the signal end of the parameter measuring instrument is connected to a data acquisition card of the power quality management platform, and the outlet pressure gauge is connected to the grid-connected computer of the distributed power grid-connected control unit through a wireless signal.

[0015] According to a second aspect of the embodiments of the present disclosure, the high-pressure natural gas pressure energy extracted from the injection and production well of the gas storage is converted into electric energy by using the above-mentioned gas storage pressure energy power generation system, according to the peak regulation demand of the power grid, the electric energy is safely and reliably connected to the power grid through a grid-connected control method, and the low-pressure gas meeting the gas transmission requirements is sent to each natural gas transmission pipeline, which comprises:

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

[0017] Starting the switches and devices of the gas storage pressure energy power generation system;

[0018] Real-time monitoring of power quality, grid-connected control according to load demand;

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

[0020] In one of the embodiments, the pre-generation state of the gas storage pressure power generation system is set in the following manner:

[0021] The device state is initialized, i.e., each load side disconnector, circuit breaker, bus side disconnector is in an open state, the protection disconnector, line side disconnector, main circuit breaker, grid side disconnector is in an open state, and the metering data of each electric energy meter is cleared;

[0022] The injection-production well to be produced and the corresponding gas production time range are determined according to the gas production plan of the gas storage, and the union of the sets [tt1 tt2], [tt2 tt3]… is represented by [tt0 tt

[0023] The union of the sets [tt1 tt2], [tt2 tt3]… is found, and is represented by [tt0 tt n ];

[0024] The injection station where the injection-production well to be produced is located is named as the "power generation injection station";

[0025] The switch devices connected with the "power generation injection station" in the distributed power grid connection control unit are found, including the load side disconnector, circuit breaker and bus side disconnector, and the labels thereof are stored in column vectors K, M and N in the order from small to large, i.e., the first row elements of the column vectors K, M and N are the minimum values, and the last row elements are the maximum values.

[0026] In one of the embodiments, the switches and devices of the gas storage pressure power generation system are started in the following manner:

[0027] The protection disconnector is controlled to be in a closed state;

[0028] The bus side disconnectors corresponding to the elements in the closed vector N are closed;

[0029] The load side disconnectors corresponding to the elements in the closed vector K are closed;

[0030] The circuit breakers corresponding to the elements in the closed vector M are closed;

[0031] The data acquisition cards connected with the "power generation injection station" in the power quality management platform are started, and the reactive power controller and reactive power compensation device start to work;

[0032] The energy conversion unit in the "power generation injection station" is started, and the injection-production well to be produced starts to produce gas.

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

[0034] Step 3.1: Store the index of the "power-generating injection station" into column vector W, and set the first row of the column vector W to the minimum value and the last row to the maximum value;

[0035] Step 3.2: Let Δt be the unit interval time, t be the gas production time, b be the calculation times, and δ be the delay time;

[0036] Step 3.3: t = tt0 + bΔt;

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

[0038] Step 3.5: Let k be the index of the "power-generating injection station", and set its value to the element of the ith row of the column vector W;

[0039] Step 3.6: Monitor the natural gas pressure flowing into the energy conversion unit k by the inlet pressure gauge, and transmit the value P k (t) to the grid computer of the distributed power grid control unit;

[0040] Step 3.7: If P k (t) = 0, it means that there is no gas flowing in, and proceed to Step 3.17; if P k (t) > 0, proceed to Step 3.8; if P k (t) < 0, output a fault signal;

[0041] Step 3.8: If P k (t) is lower than the minimum gas transmission pressure required by the gas pipeline, an alarm signal is sent, the natural gas is transmitted to the pressurization system of the injection station through the pressurization system interface, and the corresponding energy conversion unit is closed; if P k (t) is higher than the minimum gas transmission pressure required by the gas pipeline, the high-pressure gas pressure regulating valve is opened, the expander and generator are working, and the pressure energy is converted into electrical energy;

[0042] Step 3.9: Monitor the natural gas pressure flowing out of the energy conversion unit by the outlet pressure gauge, and transmit the value PP k (t) to the grid computer of the distributed power grid control unit;

[0043] Step 3.10: If PP k (t) is within the range of the gas transmission pressure required by the gas pipeline, the gas valve is opened, and the natural gas is transmitted to the gas pipeline; if PP k (t) is lower than the minimum gas transmission pressure, an alarm signal is sent, and the natural gas is transmitted to the pressurization system of the injection station through the pressurization system interface; if PP k (t) is higher than the maximum gas transmission pressure, an alarm signal is sent, and the natural gas is transmitted to the pressure reduction system of the injection station through the pressure reduction system interface;

[0044] Step 3.11: An inlet thermometer monitors the temperature of the natural gas flowing into the energy conversion unit and transmits the value T k (t) to the grid computer of the distributed electric energy grid connection control unit; an outlet thermometer monitors the temperature of the natural gas flowing out of the energy conversion unit and transmits the value TT k (t) to the grid computer of the distributed electric energy grid connection control unit;

[0045] Step 3.12: A gas flow meter monitors the cumulative flow of the natural gas flowing into the expander k and transmits the value G k (t) to the grid computer of the distributed electric energy grid connection control unit;

[0046] Step 3.13: Real-time monitoring of the electric energy quality of the generator k is performed;

[0047] Step 3.14: The energy conversion efficiency of the generator k is obtained;

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

[0049] Step 3.16: Control of the grid-connected electric energy is performed;

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

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

[0052] In one embodiment, real-time monitoring of the electric energy quality of the generator k is performed in the following manner:

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

[0054] According to the t-time parameter, the voltage offset percentage U k (t) % output by the generator k is obtained, as shown in formula 1:

[0055]

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

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

[0058]

[0059] If |U k (t) % | is less than the allowable deviation value, the next step is to determine whether Q k (t) is less than the allowable deviation value; if |U k (t) % | is not less than the allowable deviation value, output “voltage deviation unqualified”, determine the capacity of reactive power compensation required 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 the value of |U k (t) % |;

[0060] If Q k (t) is less than the allowable deviation value, return to the previous step to determine whether |U k (t) % | is less than the allowable deviation value; if Q k (t) is not less than the allowable deviation value, output “three-phase unbalance degree unqualified”, determine the unbalanced load to be reduced according to the power flow calculation model, and cut off the unbalanced load 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 in the following specific manner:

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

[0063]

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

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

[0066] The energy conversion efficiency η k (t) is obtained and stored in the b-th row of the k-th column vector of the vector group Y, η k (t) is obtained in the manner shown in equation (4):

[0067]

[0068] Wherein, W k (t) is the cumulative power generation of generator i at time t, with the unit of kWh, W k (t-Δt) is the cumulative power generation of generator k at time (t-Δt), with the unit of kWh, W k (t) and W k (t-Δt) are measured by the electric energy meter k; ρ is the density of natural gas, with the unit of kg / m 3 , G k (t-Δt) is the cumulative natural gas flow into expander k at time (t-Δt), with the unit of m 3 , G k (t) and G k (t-Δt) are transmitted to the grid-connected computer through the concentrator from the control end of the gas flow meter.

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

[0070] The grid-connected computer based on the distributed electric energy grid-connected control unit calculates the loads of each low-voltage load interface at time t, and the obtained results are represented by P1+jQ1, P1+jQ2, …, P m +jQ m ;

[0071] It is determined whether the active power generated by each generator meets the requirements of the low-voltage load, and the remaining active power is obtained.

[0072] determine whether the reactive power generated by each generator meets the low-voltage load requirement to obtain the remaining reactive power;

[0073] output the total remaining active power A = A1 + A2 + … + A z + ….

[0074] output the total remaining reactive power B = B1 + B2 + … + B z + ….

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

[0076] According to the power flow calculation model and B, the grid-connected computer of the distributed power grid-connected control unit calculates the supply reactive power at the 10kV calculation point at time t, and the result is D, while the supply active power C ≤ 0, and then perform the step of determining the relationship between the 10kV supply active power C and the 10kV active load E;

[0077] According to the power flow calculation model and A, the grid-connected computer of the distributed power grid-connected control unit calculates the supply active power at the 10kV calculation point at time t, and the result is C, while the supply reactive power D ≤ 0, and then perform the step of determining the relationship between the 10kV supply active power C and the 10kV active load E;

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

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

[0080] Determine the relationship between 10kV supply reactive power D and 10kV reactive load F: if D≥F, output 10kV surplus reactive power L=D-F; if D<F and D≤0, output 10kV surplus reactive power L=0, and prompt the staff that it is impossible to provide reactive power to all 10kV loads, all 35kV loads and the grid connection point; if D<F and D>0, output 10kV surplus reactive power L=0, and prompt the staff that it is impossible to provide reactive power to part of 10kV loads, all 35kV loads and the grid connection point;

[0081] According to the power flow calculation model and H+jL, the grid-connected computer with distributed electric energy grid-connected control unit calculates the supply power at the 35kV calculation point at time t, and the result is M+jN;

[0082] Determine the relationship between 35kV supply active power M and 35kV active load R: if M≥R, output 35kV surplus active power T=M-R; if M<R and M≤0, output 35kV surplus active power T=0, and prompt the staff that it is impossible to provide active power to all 35kV loads and the grid connection point; if M<R and M>0, output 35kV surplus active power T=0, and prompt the staff that it is impossible to provide active power to part of 35kV loads and the grid connection point;

[0083] Determine the relationship between 35kV supply reactive power N and 35kV reactive load S: if N≥S, output 35kV surplus reactive power W=N-S; if N<S and N≤0, output 35kV surplus reactive power W=0, and prompt the staff that it is impossible to provide reactive power to all 35kV loads and the grid connection point; if N<S and N>0, output 35kV surplus reactive power W=0, and prompt the staff that it is impossible to provide reactive power to part of 35kV loads and the grid connection point;

[0084] According to the power flow calculation model and T+jW, the grid-connected computer with distributed electric energy grid-connected control unit calculates the supply power at the grid connection point at time t, and the result is X+jY;

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

[0086] Determine the size of X c , Y c : if X c >0 and Y c >0, output "active power and reactive power can be transmitted to the grid connection point at the same time"; if X c ≤0 and Y cIf X ≤ 0, output "Unable to deliver active and reactive power to the grid connection point"; if X c >0 and Y c If X ≤ 0, the output will be "Only active power can be supplied to the grid connection point, but reactive power cannot be supplied to the grid connection point"; if X c ≤0 and Y c >0, outputs "Can only deliver reactive power to the grid connection point, cannot deliver active power to the grid connection point";

[0087] Based on the power supply demand of the grid connected to the grid connection point, determine the active and reactive power injected into the grid at the grid connection point.

[0088] In one embodiment, the method for determining whether the active power output of each generator meets the low-voltage load requirements is as follows:

[0089] Let the initial value of the loop variable z be 1;

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

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

[0092] In one embodiment, the determination of whether the reactive power generated by each generator meets the low-voltage load requirements is specifically carried out as follows:

[0093] Let the initial value of the loop variable z be 1;

[0094] If the reactive power Q generated by generator z fz Greater than or equal to low-voltage reactive load Q z This indicates that generator z can satisfy Q. z The demand is to output the remaining reactive power B. z =Q fz -Q z If the reactive power Q generated by generator z fz Less than the low-voltage reactive load Q z This indicates that generator z cannot satisfy Q. z The demand for Bz = 0, prompting the staff to switch the standby power supply;

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

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

[0097] The power demand at time t in the daily load curve of the power grid connected to the grid connection point is found, wherein the active power demand and the reactive power demand are represented as X w , Y w , respectively.

[0098] If X c ≤ X w , the active power X c is injected into the power grid; if X c > X w , X w is injected into the power grid, and the remaining active power X u = X c - X w at the grid connection point is injected into the battery through the battery interface.

[0099] If Y c ≤ Y w , X c is injected into the power grid; if Y c > Y w , Y w is injected into the power grid, and the remaining reactive power Y u = Y c - Y w at the grid connection point is compensated for by the reactive power compensation device of the power quality management platform.

[0100] In one embodiment, the switches and devices of the gas storage pressure energy power generation system are closed in the following manner:

[0101] The energy conversion unit in the "power-generating injection station" is closed.

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

[0103] All circuit breakers corresponding to the elements in vector M are disconnected.

[0104] All load side disconnectors corresponding to the elements in vector K are disconnected.

[0105] All bus side disconnectors corresponding to the elements in vector N are disconnected.

[0106] Compared with the prior art, the above technical scheme has the advantages that:

[0107] The application can monitor power quality in real time, intelligently distribute power according to load demand, automatically optimize power flow calculation model in grid-connected control strategy, dynamically evaluate and analyze energy conversion efficiency, and significantly improve stability and controllability of output power.

[0108] In addition, the application not only promotes recycling of energy, improves energy utilization efficiency, and effectively reduces carbon emissions, but also accurately responds to load demand of the power grid, flexibly injects power, quantitatively analyzes conversion efficiency between pressure energy and electric energy, ensures power quality, and effectively saves investment cost. BRIEF DESCRIPTION OF DRAWINGS

[0109] The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the application and are incorporated herein for explanation by reference. The illustrations in the drawings for the preferred embodiments of the present application are described in the specification to explain the present application, and do not constitute an inappropriate limitation on the present application.

[0110] Figure 1 is a schematic diagram of a gas storage pressure energy power generation system;

[0111] Figure 2 is a schematic diagram of an energy conversion unit;

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

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

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

[0115] The present disclosure will be further described below in conjunction with the accompanying drawings and examples.

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

[0117] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate 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 pressure energy power generation system including m energy conversion units, a distributed power grid-connected control unit, and a power quality management platform, where 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 governor, a generator, a current transformer, a parameter measuring instrument, and an electricity meter. The inlet pressure gauge measures the pressure of the outflowing gas purification device and transmits the data wirelessly to the grid-connected computer of the distributed power grid control unit. It also determines the relationship between this pressure and the expander inlet pressure. 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 via the inlet pressure regulating valve. The outlet pressure gauge measures the pressure of the outflowing outlet pressure regulating valve and transmits the data wirelessly to the grid-connected computer of the distributed power grid control unit. It also determines the relationship between this pressure and the gas pipeline input pressure. If the pressure is less than the minimum input pressure of the gas pipeline, the gas needs to be pressurized by the pressurization system before being output to the gas pipeline. If the pressure is greater than the maximum input pressure of the gas pipeline, the gas needs to be depressurized by the depressurization system before being output to the gas pipeline. In this embodiment, the preferred models for the inlet and outlet pressure gauges are MD-S270 with a range of 0–100 MPa, and the preferred models for the inlet and outlet pressure regulating valves are ZZYP-16C.

[0121] The inlet thermometer is used for measuring the temperature of the gas flowing into the expander and transmitting to the grid computer of the distributed power grid connection control unit through the RS485 communication bus; the outlet thermometer is used for measuring the temperature of the gas flowing out of the outlet pressure stabilizing valve and transmitting to the grid computer of the distributed power grid connection control unit through the RS485 communication bus; the gas flow meter is used for measuring the flow of the gas flowing into the expander and transmitting to the grid computer of the distributed power grid connection control unit through the RS485 communication bus; the electric energy meter is used for measuring the electric energy generated by the generator; and the gas valve is used for controlling the flow rate of the gas flowing into the gas pipeline; in the 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 flow meter is preferably LWQ-DN100;

[0122] The expander is a screw expander, which is used for converting pressure energy into mechanical energy on the screw; and the speed regulator is used for adjusting the rotating speed of the screw of the expander; the generator is a permanent magnet synchronous generator, which outputs 0.4kV alternating current; the current transformer is used for reducing the output current of the generator to a small current within the measuring range of the parameter measuring instrument according to the variable ratio, and in addition, the current transformer can also protect the parameter measuring instrument; and the parameter measuring instrument is used for measuring the voltage, current, power factor and three-phase voltage unbalance degree of the output of the generator, and transmitting the parameters to the power quality management platform through the signal end; in the embodiment, the model of the current transformer is preferably LMZJ1, and the model of the parameter measuring instrument is preferably YP9830.

[0123] As shown in Figure 3 The distributed power grid connection control unit includes a grid computer, a concentrator, a box-type transformer, a current collecting 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 protection disconnector, a circuit breaker, a fuse, a voltage transformer, a total electric energy meter and a step-up transformer.

[0124] The grid computer is used for storing the measurement results of the total electric energy meter, and storing the gas flow, inlet temperature, outlet temperature, inlet pressure and outlet pressure of a plurality of energy conversion units, for issuing control instructions of the load side disconnector, the bus side disconnector and the circuit breaker, for issuing control instructions of the line side disconnector, the main circuit breaker, the grid side disconnector and the protection disconnector, and for load calculation and power flow calculation; the concentrator is used for collecting the signal lines of the total electric energy meter, the gas flow meter, the inlet thermometer and the outlet thermometer, and for collecting the control lines of the load side disconnector, the bus side disconnector, the circuit breaker, the line side disconnector, the main circuit breaker, the grid side disconnector and the protection disconnector; in the embodiment, the preferred model of the grid computer is RTX4090, and the preferred model of the concentrator is JT-4MFL, which can allow access to 256 RS485 communication lines.

[0125] The box-type transformer raises the 0.4 kV voltage outputted by the generator to 10 kV, the transformation ratio is 0.4 kV / 10 kV, the collecting bus is used to collect the electric energy outputted by the multiple energy conversion units, the voltage level is 10 kV, the filter is used to filter the high-order harmonic wave in the line, the load-side disconnecting switch, the bus-side disconnecting switch and the circuit breaker are used to control the on-off of the output current of each energy conversion unit; the step-up transformer raises the 10 kV voltage outputted by the collecting bus to 35 kV, the transformation ratio is 10 kV / 35 kV; the 35 kV bus is used to collect the 35 kV electric energy outputted by the step-up transformer, the line-side disconnecting switch, the main circuit breaker and the grid-side disconnecting switch are used to control the on-off of the grid current at the grid connection point, the total electric energy meter is used to measure the electric quantity of the grid connection point; the protection disconnecting switch is used to control whether the voltage transformer is connected to the 35 kV bus, the fuse is used to prevent the voltage transformer and its lead from affecting the high-voltage system due to fault, and the voltage transformer is used to measure the 35 kV bus voltage and prevent overvoltage; in the embodiment, the filter is of the XNAPF type, the filterable harmonic wave range is 2-50, the circuit breaker is of the ZW32 type, the rated voltage is 10 kV, the main circuit breaker is of the ZW7 type, the rated voltage is 35 kV, the load-side disconnecting switch and the bus-side disconnecting switch are both of the GN19-10 type, the protection disconnecting switch, the line-side disconnecting switch and the grid-side disconnecting switch are all of the GW5-35 type, the total electric energy meter is of the DTSD341 type, and the voltage transformer is of the JDZX9-35 type, and the fuse is of the HRW12-35 type;

[0126] As shown in Figure 4 , the electric energy quality management platform comprises 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 electric quantity, voltage, current, power factor and three-phase voltage unbalance degree outputted by each energy conversion unit, and is used to issue a control instruction of compensation capacity; the reactive power compensation controller controls the reactive power compensation device to output the required compensation capacity, the reactive power compensation device is used to compensate the reactive power at the low-voltage side of the box-type transformer and the grid connection point, and ensure the electric energy quality; the CAN bus is of the BT1207 type, the CAN adapter card is used to convert the CAN interface into a USB interface, and is of the CANalyst-II type; the RS485 communication bus is of the ADM-2542 type, and the data acquisition card is used to acquire the signals measured by the parameter measuring instrument, and is of the C-7017 type;

[0128] Embodiment 2

[0129] As shown in Figure 5As shown, the embodiment provides a gas purification device, which comprises 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 and metering of oil, gas, and water, and the pre-cooler is used to cool the natural gas to a specified temperature, which is 25℃ in the embodiment; 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 respectively used to measure the temperature of the wet gas and the dry gas, and the preferred model is CYT521F, the temperature measurement range is -200-600℃, and the explosion-proof grade is EXdⅡCT6.

[0131] Embodiment 3

[0132] The pressure energy of the high-pressure natural gas extracted from the injection-production well of the gas storage is converted into electric energy by using the gas storage pressure energy power generation system of the embodiment 1, and according to the peak shaving demand of the power grid, the electric energy is safely and reliably connected to the power grid through the grid-connected control method, and the low-pressure gas meeting the gas transmission requirements is sent to each natural gas transmission pipeline, including:

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

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

[0135] Step 1.2: Determine the injection-production well to be extracted and the corresponding gas extraction time range according to the gas extraction plan of the gas storage, which are represented by sets [tt1 tt2], [tt2 tt3]…… respectively;

[0136] Step 1.3: Find the union of the sets [tt1 tt2], [tt2 tt3]…… in step 1.2, and represent it as [tt0 tt n ];

[0137] Step 1.4: Name the injection station where the injection-production well to be extracted as “power generation injection station”;

[0138] Step 1.5: Find the switch devices connected to the “power generation injection station” in the distributed electric energy grid-connected control unit, including load side disconnectors, circuit breakers, and bus side disconnectors, and store their labels in column vectors K, M, and N in the order from small to large, i.e., the first row elements of the column vectors K, M, and N are the minimum values, and the last row elements are the maximum values;

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

[0140] Step 2.1: Control the protection isolating switch to be in the closed state;

[0141] Step 2.2: Close all busbar side isolating switches corresponding to the elements in vector N;

[0142] Step 2.3: Close all load side isolating switches 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 with the "power generation injection station" in the power quality management platform, and the reactive power controller and reactive power compensation device start to work;

[0145] Step 2.6: Start the energy conversion unit in the "power generation injection station", and the injection-production well starts to produce gas;

[0146] Step 3: Real-time monitoring of power quality, and grid-connected control according to load demand;

[0147] Step 3.1: Store the index of the "power generation injection station" into column vector W, that is, the first row elements of column vector W are all minimum values, and the last row elements are all maximum values;

[0148] Step 3.2: Let Δt be the unit interval time, unit h; t be the gas production time, unit h; b be the calculation times, initial value 1; δ be the delay time, unit h;

[0149] Step 3.3: t = tt0 + bΔt;

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

[0151] Step 3.5: Let k be the index of the "power generation injection station", and the value of k is the element of the i-th row in column vector W;

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

[0153] Step 3.7: Determine whether P k (t) is equal to 0: if P k (t) = 0, it means that there is no gas flowing in, and step 3.17 is performed; if P k (t) > 0, step 3.8 is performed; if P k (t) < 0, output a fault signal;

[0154] Step 3.8: judge P k (t) whether it is lower than the minimum value of the gas transmission pressure required by the gas transmission pipeline: if it is lower than the minimum value of the gas transmission pressure, an alarm signal is sent, the natural gas is transmitted to the pressurization system of the central injection station through the pressurization system interface, and the corresponding energy conversion unit is closed, if it is higher than the minimum value of the gas transmission pressure, the high-pressure gas pressure stabilizing valve is opened, the expander and the generator work, and the pressure energy is converted into electric energy;

[0155] Step 3.9: the outlet pressure gauge monitors the pressure of the natural gas flowing out of the energy conversion unit, and the value PP k (t) is transmitted to the grid computer of the distributed electric energy grid connection control unit;

[0156] Step 3.10: judge whether PP k (t) is within the range of the gas transmission pressure required by the gas transmission pipeline: if it is within the range, the gas valve is opened, the natural gas is transmitted to the gas transmission pipeline, if it is lower than the minimum value of the gas transmission pressure, an alarm signal is sent, the natural gas is transmitted to the pressurization system of the central injection station through the pressurization system interface, if it is higher than the maximum value of the gas transmission pressure, an alarm signal is sent, the natural gas is transmitted to the pressure reduction system of the central injection 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 the value T k (t) is transmitted to the grid computer of the distributed electric energy grid connection control unit; the outlet thermometer monitors the temperature of the natural gas flowing out of the energy conversion unit, and the value TT k (t) is transmitted to the grid computer of the distributed electric energy grid connection control unit;

[0158] Step 3.12: the gas flow meter monitors the cumulative flow of the natural gas flowing into the expander k, and the value G k (t) is transmitted to the grid computer of the distributed electric energy grid connection control unit;

[0159] Step 3.13: real-time monitoring of the electric energy quality of the generator k;

[0160] Step 3.13.1: the parameter measuring instrument transmits the parameters output by the generator k at t time to the electric energy quality management platform through the signal end, including: voltage U k (t), current I k (t), power factor three-phase voltage voltage unbalance degree Q k (t);

[0161] Step 3.13.2: according to the parameters measured in step 3.13.1, the voltage offset percentage U k (t) % of the generator k output is obtained, as shown in formula 1:

[0162]

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

[0164] Step 3.13.3: store U k (t) % in the b-th row of the k-th column vector of the column vector group X, and the vector group X is shown in formula (2):

[0165]

[0166] Step 3.13.4: determine whether |U k (t) % | is 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 unqualified”, determine the capacity of reactive power compensation required 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 the value of |U k (t) % |;

[0167] Step 3.13.5: determine whether Q k (t) is 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 degree unqualified”, determine the unbalanced load to be reduced according to the power flow calculation model, and cut off 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 the generator k;

[0169] Step 3.14.1: calculate the pressure energy flowing into the expander k according to the natural gas theoretical value, as shown in formula (3);

[0170]

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

[0172] Step 3.14.2: Store the E k (t) calculated in step 3.14.1 into the bth row of the kth column vector in column vector group V;

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

[0174]

[0175] Where, W k (t) is the cumulative power generation of generator i at t, with the unit of kWh, W k (t-Δt) is the cumulative power generation of generator k at (t-Δt), with the unit of kWh, W k (t) and W k (t-Δt) are measured by the electric energy meter k; ρ is the density of natural gas, with the unit of kg / m 3 , G k (t-Δt) is the cumulative natural gas flow into the expander k at (t-Δt), with the unit of m 3 , G k (t) and G k (t-Δt) are transmitted to the grid-connected computer through the concentrator from the control end of the gas flow meter;

[0176] Step 3.15: Determine whether k is the element in the last row of column vector W: if not, let i=i+1, repeat steps 3.5-3.14; 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 electric energy grid-connected control unit calculates the load of each low-voltage load interface at t, and the obtained results are 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 requirement;

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

[0181] Step 3.16.2.2: Determine whether the active power P fz output by generator z is greater than or equal to the low-voltage active load P z : If P fz ≥ P z , it means that generator z can meet the demand of P z , and output the remaining active power A z = P fz - P z ; if P fz < P z , it means that generator z cannot meet the demand of P z , and let A z = 0, prompting the staff to switch to the standby power supply;

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

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

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

[0185] Step 3.16.3.2: Determine whether the reactive power Q fz output by generator z is greater than or equal to the low-voltage reactive load Q z : If Q fz ≥ Q z , it means that generator z can meet the demand of Q z , and output the remaining reactive power B z = Q fz - Q z ; if Q fz < Q z , it means that generator z cannot meet the demand of Q z , and let B z = 0, prompting the staff to switch to the standby power supply;

[0186] Step 3.16.3.3: Determine whether z is the element of the last row in column vector W: if not, let z = z + 1, and repeat Step 3.16.3.2; if yes, 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 remaining reactive power B = B1 + B2 +... + B z +... ;

[0189] Step 3.16.6: Determine 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 "The power generation system cannot provide active power and reactive power to all 10kV loads, all 35kV loads, and the grid point", and then proceed to Step 3.17;

[0190] Step 3.16.7: According to the power flow calculation model and the output B of Step 3.16.5, use the computer of the distributed power grid control unit to calculate the supply reactive power at the 10kV calculation point at time t, and the result is D, while the supply active power C ≤ 0, then proceed to Step 3.16.10;

[0191] Step 3.16.8: According to the power flow calculation model and the output A of Step 3.16.4, use the computer of the distributed power grid control unit to calculate the supply active power at the 10kV calculation point at time t, and the result is C, while the supply reactive power D ≤ 0, then proceed to Step 3.16.10;

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

[0193] Step 3.16.10: Determine the relationship between 10kV supply active power C and 10kV active load E: if C ≥ E, output 10kV remaining active power H = C - E; if C < E and C ≤ 0, output 10kV remaining active power H = 0, and prompt the staff that it is not possible to provide active power to all 10kV loads, all 35kV loads, and the grid point; if C < E and C > 0, output 10kV remaining active power H = 0, and prompt the staff that it is not possible to provide active power to part of the 10kV loads, all 35kV loads, and the grid point;

[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 the remaining 10kV reactive power L = DF; if D < F and D ≤ 0, output the remaining 10kV reactive power L = 0, indicating to staff that reactive power cannot be provided to all 10kV loads, all 35kV loads, and grid connection points; if D < F and D > 0, output the remaining 10kV reactive power L = 0, indicating to staff that reactive power cannot be provided 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 control unit is used to calculate the power supply at the 35kV calculation point at time t, and the result is denoted 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 the remaining active power of 35kV T = MR; if M < R and M ≤ 0, output the remaining active power of 35kV T = 0, indicating to staff that active power cannot be provided to all 35kV loads and grid connection points; if M < R and M > 0, output the remaining active power of 35kV T = 0, indicating to staff that active power cannot be provided 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 the remaining 35kV reactive power W=NS; if N<S and N≤0, output the remaining 35kV reactive power W=0, indicating to staff that reactive power cannot be provided to all 35kV loads and grid connection points; if N<S and N>0, output the remaining 35kV reactive power W=0, indicating to staff that reactive power cannot be delivered to some 35kV loads and grid connection points.

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

[0199] Step 3.16.16: Based on the power supply X at the grid connection point measured by the total power meter at time t... c +jY c The calculation result X+jY from step 3.16.15 is used to correct the power flow calculation model used in this invention based on the neural network algorithm, thereby improving the accuracy of the next calculation.

[0200] Step 3.16.17: Determine Xc , Y c ; c > 0 and Y c > 0, output "active power and reactive power can be delivered to the grid point simultaneously"; if X c ≤ 0 and Y c ≤ 0, output "active power and reactive power cannot be delivered to the grid point"; if X c > 0 and Y c ≤ 0, output "only active power can be delivered to the grid point, and no reactive power can be delivered to the grid point"; if X c ≤ 0 and Y c > 0, output "only reactive power can be delivered to the grid point, and no active power can be delivered to the grid point";

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

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

[0203] Step 3.16.18.2: Compare the sizes of X c and X w : if X c ≤ X w , inject active power X c into the grid; if X c > X w , inject X w into the grid, and at the same time inject the remaining active power X u = X c - X w of the grid point into the battery through the battery interface;

[0204] Step 3.16.18.3: Compare the sizes of Y c and Y w : if Y c ≤ Y w , inject X c into the grid; if Y c > Y w , inject Y w into the grid, and at the same time perform reactive power compensation on the remaining reactive power Y u = Y c - Y w of the grid point through the reactive power compensation device of the power quality management platform;

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

[0206] Step 3.18: take all elements of the kth column vector in the column vector group Y, and draw a curve f k (t) with time t as the horizontal axis and energy conversion efficiency η k (t) as the vertical axis;

[0207] Step 4: turn off the switches and devices of the gas storage pressure energy power generation system;

[0208] Step 4.1: turn off the energy conversion unit in the "power-generating injection station";

[0209] Step 4.2: the data acquisition card connected with the "power-generating 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 only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0214] The above describes the specific embodiments of the present disclosure in conjunction with the accompanying drawings, but is not a limitation on the protection scope of the present disclosure. Those skilled in the art should understand that various modifications or changes made on the basis of the technical solutions of the present disclosure without creative labor are still within the protection scope of the present disclosure.

Claims

1. A grid-connected control method for a gas storage pressure energy power generation system, characterized in that, include: Pre-generation state setting for the pressure energy power generation system of the gas storage facility; Start the switches and equipment of the gas storage pressure energy power generation system; Real-time monitoring of power quality and grid connection control based on load demand; After the power supply is completed, shut down the switches and equipment of the gas storage pressure energy power generation system; The pre-generation state setting for the gas storage pressure energy power generation system is performed as follows: The equipment status is initialized, that is, the load-side disconnect switches, circuit breakers, and bus-side disconnect switches are in the open state, the protection disconnect switches, line-side disconnect switches, main circuit breakers, and grid-side disconnect switches are in the open state, and the metering data of each energy meter is cleared to zero; Based on the gas production plan of the gas storage facility, determine the injection and production wells to be produced and the corresponding production time range, using a set [ tt 1 tt 2]、[ tt 2 tt 3]... indicates; Find the set [ tt 1 tt 2]、[ tt 2 tt The union of 3]... is expressed by [ tt 0 tt n ]express; The injection and production station where the gas injection and production wells to be extracted are located will be named "Power Generation Injection and Production Station"; Locate the switching equipment connected to the "power generation and injection station" in the distributed power grid-connected control unit, including load-side disconnect switches, circuit breakers, and bus-side disconnect switches, and store their labels in column vectors in ascending order. K , M and N That is, column vector K , M and N The first row contains all minimum values, and the last row contains all maximum values.

2. The grid-connected control method for a gas storage pressure energy power generation system according to claim 1, characterized in that, The specific steps for starting the switches and equipment of the gas storage pressure energy power generation system are as follows: The control and protection disconnect switch is in the closed state; Closed vector N All bus-side disconnect switches corresponding to the internal element; Closed vector K All load-side disconnect switches corresponding to the internal element; Closed vector M All circuit breakers corresponding to the internal element; The data acquisition card connected to the "power generation and injection station" in the power quality management platform is activated, and the reactive power controller and reactive power compensation device begin to work; The energy conversion unit within the "power-generating injection station" is activated, and the injection-production wells awaiting gas extraction begin gas production.

3. The grid-connected control method for a gas storage pressure energy power generation system according to claim 1, characterized in that, Real-time monitoring of power quality and grid-connected control based on load demand are implemented in the following ways: Step 3.1: Store the labels of "Power Generation and Injection Stations" into a column vector. W Its column vector W The first row contains all minimum values, and the last row contains all maximum values. Step 3.2: Let t The interval is measured in hours (h). t This refers to the gas extraction time, expressed in hours (h). b The initial value is 1 for the number of calculations; δ is the delay time in hours. Step 3.3: t = tt 0+ b t ; Step 3.4: Let i This is the loop variable, and its initial value is 1. Step 3.5: Let k This is the designation for a "power-generating injection station". k The value is a column vector W The Middle i Row elements; Step 3.6: Inlet pressure gauge monitors the inflow of the first... k Natural gas pressure value of each energy conversion unit P k ( t ), and set the value P k ( t The data is transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.7: If P k ( t If )=0, it means no gas is flowing in; proceed to step 3.

17. P k ( t If ) > 0, proceed to step 3.8; if P k ( t If the value is less than 0, output a fault signal; Step 3.8: If P k ( t If the gas pressure is lower than the minimum required for the gas pipeline, an alarm signal will be issued, and natural gas will be transported to the pressurization system of the gas gathering and injection station through the pressurization system interface, and the corresponding energy conversion unit will be shut down. like P k ( t When the gas pressure exceeds the minimum required for the gas pipeline, the high-pressure gas stabilizing valve opens, and the expander and generator start working, converting pressure energy into electrical energy. Step 3.9: Monitor the pressure value of natural gas flowing out of the energy conversion unit using the outlet pressure gauge. PP k ( t ), and set the value PP k ( t The data is transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.10: If PP k ( t If the gas pressure is within the required range for the gas pipeline, the gas valve will open, allowing natural gas to be delivered to the pipeline. PP k ( t If the gas pressure falls below the minimum transmission pressure, an alarm signal is issued, and natural gas is supplied to the pressurization system of the gathering and injection station via the pressurization system interface. PP k ( t If the pressure exceeds the maximum value of the gas transmission pressure, an alarm signal will be issued, and the natural gas will be transmitted to the pressure reduction system of the gas gathering and injection station via the pressure reduction system interface; Step 3.11: The inlet thermometer monitors the temperature of the natural gas flowing into the energy conversion unit. T k ( t ), and set the value T k ( t The data 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. TT k ( t ), and set the value TT k ( t The data is transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.12: Gas flow meter monitors the inflow of gas into the first... k Cumulative natural gas flow rate of each expander G k ( t ), and set the value G k ( t The data is transmitted to the grid-connected computer of the distributed power grid-connected control unit; Step 3.13: For the first k Real-time monitoring of the power quality of each generator; Step 3.14: Obtain the first k Energy conversion efficiency of a generator; Step 3.15: If k Not a column vector W The element in the last row of the middle, let i = i +1, repeat steps 3.5 to 3.14; if k It is a column vector W Find the last element in the loop, end the loop, and proceed to step 3.16; Step 3.16: Control the grid-connected power supply; Step 3.17: If t < tt n ,make b = b +1, repeat steps 3.3~3.16, if t ≥ tt n End the loop and proceed to step 3.18; Step 3.18: Obtain energy conversion efficiency η k ( t ), and store it into a vector group. Y The Middle k The column vector of the th ... b Rows, take column vectors Y The Middle k All elements of a column vector, plotted in time t The horizontal axis represents energy conversion efficiency. η k ( t The curve with the vertical axis as the y-axis f k ( t ).

4. The grid-connected control method for a gas storage pressure energy power generation system according to claim 3, characterized in that, For the k The power quality of each generator is monitored in real time, specifically as follows: The parameter measuring instrument transmits the first parameter through the signal terminal. k The output of each generator t Time parameters are transmitted to the power quality management platform, including: voltage. U k ( t ), current I k ( t ), power factor cos φ k ( t Three-phase voltage imbalance Q k ( t ); according to t Time parameters, to obtain the first k Percentage of voltage deviation from generator output U k ( t )%, as shown in Equation 1: （1） in, U k ( t () represents the actual generator voltage measured by a parameter measuring instrument, in volts (V). U N The generator's rated voltage is expressed in volts (V). The voltage offset percentage U k ( t )% Store in column vector group O The Middle k The column vector of the th ... b Rows, vector groups O As shown in equation (2): （2） If | U k ( t If the deviation is less than the allowable value, proceed to the next step for judgment. Q k ( t Is it less than the allowable deviation value? If | U k ( t If the voltage deviation is not less than the allowable deviation value, the output will be "Voltage Deviation Unqualified". Based on the power flow calculation model, the capacity requiring reactive power compensation will be determined, and this compensation capacity will be transmitted through the power quality management platform. k A reactive power compensation interface is applied to the distributed power grid-connected control unit to reduce | U k ( t The value of )%∣; like Q k ( t If the value is less than the allowable deviation, return to the previous step | U k ( t )% | Is it less than the allowable deviation value? If Q k ( t If the unbalance is not less than the allowable deviation value, output "Three-phase unbalance is unqualified". Based on the power flow calculation model, determine the unbalanced load that needs to be reduced, and then... k A low-voltage load interface disconnects the unbalanced load from the distributed power grid control unit.

5. The grid-connected control method for a gas storage pressure energy power generation system according to claim 3, characterized in that, Get the k The energy conversion efficiency of a generator is specifically determined as follows: According to the natural gas flow theory, the inflow is... k The pressure energy of the expander is shown in equation (3); （3） in, E k ( t ) is "the k In each of the "power-generating and injection stations", every kilogram of natural gas... t The pressure energy generated at any given time is expressed in kJ / kg; C p The isobaric specific heat capacity of natural gas is expressed in kJ / (kg·K). M The molar mass of natural gas is expressed in kg / kmol. r is the molar gas constant of natural gas, with units of kJ / (kmol·K); T k ( t )for t The natural gas input temperature at any given time is measured by the inlet thermometer of the energy conversion unit; TT k ( t +δ) is t The natural gas output temperature at time +δ is measured by the outlet thermometer of the energy conversion unit. ( t )for t The natural gas input pressure at any given time is measured by the inlet pressure gauge of the energy conversion unit. PP k ( t +δ) is t The natural gas output pressure at time +δ is measured by the outlet pressure gauge of the energy conversion unit. T 0 represents the ambient temperature; Pressure energy E k ( t Store in column vector group V The Middle k The column vector of the th ... b OK; Obtaining energy conversion efficiency η k ( t ), and store it into a vector group. Y The Middle k The column vector of the th ... b OK, η k ( t The method for obtaining ) is shown in equation (4): （4） in, G k ( t () represents the cumulative flow rate of natural gas; W k ( t )for t The cumulative power generation of the k-th generator within a given time period, expressed in kWh. W k ( t - t )for( t - t Within a certain time period, the first k The cumulative power generation of each generator, in kWh. W k ( t )and W k ( t - t ) by the first k Measured by an electricity meter; ρ This refers to the density of natural gas, expressed in kg / m³. 3 G k ( t - t )for( t - t The cumulative inflow within the specified time period is the first k The natural gas flow rate of each expander, in m³ / s. 3 , G k ( t )and G k ( t - t The data is transmitted from the control terminal of the gas flow meter to the grid-connected computer via a hub.

6. The grid-connected control method for a gas storage pressure energy power generation system according to claim 3, characterized in that, The specific methods for controlling grid-connected power are as follows: Grid-connected computer based on distributed power grid-connected control unit t The load at each low-voltage load interface is calculated at any given time, and the results are used... P 1+j Q 1. P 2+j Q 2, ... P m +j Q m express; Determine whether the active power output of each generator meets the low-voltage load requirements to obtain the remaining active power; Determine whether the reactive power output of each generator meets the low-voltage load requirements to obtain the remaining reactive power; Output total residual active power A = A 1+ A 2+……+ A z +……; Output total residual reactive power B = B 1+ B 2+……+ B z +……; like A =0 and B >0, proceed t Steps for calculating the reactive power of power supply at the 10kV calculation point at a given time; like A >0 and B =0, proceed t Steps for calculating the active power of the power supply at the 10kV calculation point at a given time; like A >0 and B >0, proceed t Steps for calculating the power supply at the 10kV calculation point at a given time; like A =0 and B If the value is 0, the output will be "This power generation system is unable to provide active and reactive power to all 10kV loads, all 35kV loads, and the grid connection point," followed by a judgment. t Is it less than tt n Steps; Based on the power flow calculation model and B The grid-connected computer using the distributed power grid-connected control unit... t The reactive power of the power supply at the 10kV calculation point at time 1 is calculated, and the result is: D At the same time, it enables the active power of the power supply. C ≤0, then determine the active power of the 10kV power supply. C With 10kV active load E The steps of the relationship; Based on the power flow calculation model and A The grid-connected computer using the distributed power grid-connected control unit... t The active power of the power supply at the 10kV calculation point at time 1 is calculated, and the result is: C At the same time, it reduces the reactive power of the power supply. D ≤0, then determine the active power of the 10kV power supply. C With 10kV active load E The steps of the relationship; Based on the power flow calculation model and A +j B The grid-connected computer using the distributed power grid-connected control unit... t The power supply at the 10kV calculation point at time 1 is calculated, and the result is: C +j D Then, the active power of the 10kV power supply was determined. C With 10kV active load E The steps of the relationship; like C ≥ E Output 10kV residual active power H = C - E ; like C < E and C ≤0, output 10kV residual active power H =0, indicating that the system cannot provide active power to all 10kV loads, all 35kV loads, and the grid connection point; if C < E and C >0, output 10kV residual active power H =0, indicating that staff cannot provide active power to some 10kV loads, all 35kV loads, and grid connection points; Determine the reactive power of a 10kV power supply D With 10kV reactive load F Relationship: If D ≥ F Output 10kV residual reactive power L = D - F ;like D < F and D ≤0, output 10kV residual reactive power L =0, indicating that the system cannot 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 indicates that the staff cannot provide reactive power to some 10kV loads, all 35kV loads, and grid connection points; Based on the power flow calculation model and H +j L The grid-connected computer using the distributed power grid-connected control unit... t The power supply at the 35kV calculation point at time 3 is calculated, and the results are used... J+jI ; Determine the active power of 35kV power supply Z With 35kV active load R Relationship: If J ≥ R Output 35kV residual active power T =J- R ; If J < R And J≤0, output 35kV residual active power T =0, indicating that the staff cannot provide active power to all 35kV loads and grid connection points; If J < R And J > 0, outputting 35kV residual active power T =0, indicating that staff cannot provide active power to some 35kV loads and grid connection points; Determine the reactive power of a 35kV power supply I With 35kV reactive load S Relationship: If I ≥ S Output 35kV residual reactive power W = I - S ; like I < S and I ≤0, output 35kV residual reactive power W =0, indicating that the staff cannot provide reactive power to all 35kV loads and grid connection points; like I < S and I >0, output 35kV residual reactive power W =0, indicating that staff cannot transmit reactive power to some 35kV loads and grid connection points; Based on the power flow calculation model and T +j W The grid-connected computer using the distributed power grid-connected control unit... t The power supply capacity of the grid connection point is calculated at any given time. According to the total electricity meter reading t Power supply at grid connection point at all times X c +j Y c Based on neural network algorithms, 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, output "Can simultaneously supply active and reactive power to the grid connection point"; if X c ≤0 and Y c If ≤0, output "Unable to deliver active and reactive power to the grid connection point"; if X c >0 and Y c ≤0, output "Only active power can be delivered to the grid connection point, reactive power cannot be delivered to the grid connection point"; if X c ≤0 and Y c >0, outputs "Can only deliver reactive power to the grid connection point, cannot deliver active power to the grid connection point"; Based on the power supply demand of the grid connected to the grid connection point, determine the active and reactive power injected into the grid at the grid connection point.

7. The grid-connected control method for a gas storage pressure energy power generation system according to claim 6, characterized in that, To determine whether the active power output of each generator meets the low-voltage load requirements, the specific method is as follows: Let loop variable a The initial value is 1; If the first z The active power output of each generator P fz Greater than or equal to low-voltage active load P z Explanation of the first z One generator can meet the needs P z To meet the demand, output the remaining active power. A z = P fz - P z If the first z The active power output of each generator P fz Less than low-voltage active load P z Explanation of the first z One generator cannot meet the demand. P z The demand makes A z =0, prompting staff to switch to backup power; like a Not a column vector W The element in the last row of the middle, let a = a +1, repeat the above; if a It is a column vector W The loop ends when the last element in the loop is reached.

8. The grid-connected control method for a gas storage pressure energy power generation system according to claim 6, characterized in that, To determine whether the reactive power output of each generator meets the low-voltage load requirements, the specific method is as follows: Let loop variable a The initial value is 1; If the first z The reactive power generated by each generator Q fz Greater than or equal to low-voltage reactive load Q z Explanation No. z One generator can meet the needs Q z To meet the demand, output the remaining reactive power. B z = Q fz - Q z If the first z The reactive power generated by each generator Q fz Less than low-voltage reactive load Q z Explanation of the first z One generator cannot meet the demand. Q z The demand makes B z =0, prompting staff to switch to backup power; like a Not a column vector W The element in the last row of the middle, let a = a +1, repeat the above steps; if a It is a column vector W The loop ends when the last element in the loop is reached.

9. The grid-connected control method for a gas storage pressure energy power generation system according to claim 6, characterized in that, The active and reactive power injected into the grid at the grid connection point are determined as follows: Find the daily load curve of the power grid connected to the grid connection point. t The electricity demand at any given time, where the required active power and reactive power are expressed as follows: X w , Y w ; like X c ≤ X w active power X c Injected into the power grid; if X c > X w ,Will X w Injecting power into the grid, while simultaneously transferring the remaining active power at the grid connection point. X u = X c - X w Injected into the battery via the battery interface; like Y c ≤ Y w ,Will Y c Injected into the power grid; if Y c > Y w ,Will Y w Injected into the power grid, and simultaneously compensated for the remaining reactive power at the grid connection point through the reactive power compensation device of the power quality management platform. Y u = Y c - Y w Perform reactive power compensation.

10. The grid-connected control method for a gas storage pressure energy power generation system according to claim 1, characterized in that, The specific steps to shut down the switches and equipment of the gas storage pressure energy generation system are as follows: Shut down the energy conversion unit within the "power generation 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 vector M All circuit breakers corresponding to the internal element; Disconnect vector K All load-side disconnect switches corresponding to the internal element; Disconnect vector N All bus-side disconnect switches corresponding to the internal element.

Images