Grid-connected control method for data center diesel generator participating in demand response

Abstract

The invention provides a grid-connected control method for a data center diesel generator to participate in demand response, that is, the data center diesel generator is merged into a power grid to participate in demand response during the power utilization peak period of the power grid, and a data center power supply topology model is transformed by removing mechanical and electrical interlocking of an ATS grid-connected device. Therefore, the logic that the diesel generator is connected into the power grid to supply power simultaneously when the power grid operates normally is realized. The diesel generator is started with small power, parallel operation and grid connection are completed through quasi-synchronization, the diesel generator in the data center participates in demand response, the switching logic of the transformed topology model is further controlled, the diesel generator can work in a demand response mode and an emergency power supply mode, and impact of grid connection on a power grid is reduced as much as possible. According to the method, grid-connected control measures considering participation of the diesel generator in the demand response in the data center are provided from the control level. The technical problems that when the diesel generator in the data center participates in demand response, parallel operation and grid connection of multiple units are difficult, a topological model is not applicable, and switch control logic is disordered are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel generators participating in demand response, and in particular to a grid-connected control method for diesel generators participating in demand response in a data center. Background Art

[0002] Building a new power system with new energy as the main body is the only way to achieve the "dual carbon" goal of the power industry. The continuous increase in the proportion of new energy power generation installed capacity and grid-connected electricity has greatly weakened the flexible adjustment ability of the system power supply side. On the other hand, the random fluctuation characteristics of new energy output have put forward higher requirements on the real-time power balance ability of the system. It is unsustainable to rely solely on adjustable resources on the power supply side to maintain the power balance of the power system.

[0003] Taking into account factors such as national security and industrial development, vigorously developing the "new infrastructure" of computing power infrastructure represented by data centers has become an important strategy of my country, and its development speed leads the world. In addition to the high-voltage substation system, power generation system, and automatic transfer switch system, the internal structure of the data center is also equipped with a diesel generator backup power system, UPS system, and low-voltage distribution system. Under the condition of stable power supply from the external power grid, the diesel generators inside the data center are often idle for a long time, which will cause problems such as equipment aging and fuel degradation of the diesel generators. Not only does it pose a certain potential threat to the stable operation of the data center, but it will also generate some depreciation costs. The participation of diesel generators in data centers in demand response can not only help regulate the power grid load, but also reduce the energy consumption and operating costs of the data center itself. As a traditional and relatively mature power generation equipment, diesel generators can better participate in demand response, with the advantages of simple technology, stability and reliability, but the participation of diesel generators in data centers in demand response faces difficulties such as multi-unit paralleling, grid connection difficulty, inadaptability of the original topology model, and confusion of switch control logic. Existing research has mostly focused on studying diesel generator sets as an overall power source model and studying diesel engine grid connection at the system level. However, there is little research on the quasi-synchronous grid connection and control logic of diesel generator set power supply systems with different configurations.

[0004] In response to the above-mentioned problem of diesel engines in data centers participating in demand response, based on the diesel generator grid-connected logic transformation technology, the data center power supply topology model and switch control logic are transformed to enable the data center diesel generators to participate in demand response. Summary of the invention

[0005] The present invention proposes a grid-connected control method for a data center diesel generator participating in demand response, which is used to solve the technical problems of topology model inadaptability and switch control logic confusion when the data center diesel generator participates in demand response.

[0006] The present invention discloses a grid-connected control method for a data center diesel generator participating in demand response, comprising the following steps:

[0007] S1: Topology model transformation: In the original two-way power supply topology model, the diesel generator inlet switch is closed only when the power grid fails. The diesel generator is only used as an emergency power supply and cannot participate in demand response. It cannot meet the necessary requirements of connecting the diesel generator in parallel with the power grid when participating in demand response.

[0008] S2: Quasi-synchronous parallel connection and grid connection: When diesel generators participate in demand response, they need to be synchronously connected to the grid and paralleled to the grid. This can only be done when the conditions for quasi-synchronous parallel connection and grid connection are met. Otherwise, a large impact current will be generated and affect the power grid.

[0009] S3: Participation in demand response: After completing quasi-synchronous parallel operation, the diesel generator transmits electric energy to the grid through the grid lines, and increases the transmission capacity by increasing the number of operating units, so that the diesel generator sets can participate in demand response.

[0010] Preferably, the topology model transformation in S1 further includes the following steps:

[0011] By connecting the diesel generator set in the data center to the power grid through ATS, and removing the mechanical interlock and electrical interlock set between DL4 and DL6, DL5 and DL7 switches in the original topology model, the diesel generator set can transmit electricity to the power grid when the power grid is normally supplied. When the power grid is in the peak period of power consumption, the diesel generator starts with a small power to start quasi-synchronous parallel operation. When the parallel operation is completed, the switch DL8 is closed. When it is judged that the quasi-synchronous grid connection conditions are met, the switch DL6 is closed to achieve grid connection. When the power supply of the power grid is restored, the diesel generators exit the operation in turn. When all the diesel generators exit the operation, the switches DL8 and DL6 are disconnected to realize the removal of the diesel generators. In this way, the diesel generator set is connected to the power grid to participate in demand response. That is, when the diesel generator set is connected to the power grid, it provides power to the power grid, and the power supply of the power grid is reduced. As the output of the diesel generator continues to increase to reach the rated output power, the power reduced by the power grid is equal to the power generated by the diesel generator, thereby realizing the connection of the diesel generator set to the power grid to participate in demand response.

[0012] Preferably, when performing synchronous parallel operation and grid connection operation in S2, in order to avoid large impact current during parallel operation and grid connection, the following three conditions should be met between the generator set to be connected and the running generator set:

[0013] U1=U2 (1)

[0014] f1=f2 (2)

[0015]

[0016] Preferably, in S2, it is almost impossible to actually meet the three conditions of parallel connection and grid connection at the same time, that is, it is impossible for there to be no impact current in the system during parallel connection and grid connection. Long-term practice has proved that the following three conditions can be met when the generator sets are actually paralleled and grid connected: Δf=|f2-f1|≤0.5Hz (5)

[0017] Among them, U1 and U2 are the voltage value of the unit to be connected and the voltage value of the running unit respectively, and f1 and f2 are the frequency of the unit to be connected and the frequency of the running unit respectively. They are the voltage phase of the units to be connected and the voltage phase of the units on the grid.

[0018] Preferably, the ideal grid-connected condition for the diesel generator set in S2 is that the two vectors of the generator end and the system side bus voltage completely coincide and rotate synchronously. The voltage difference between the generator end and the system side before grid connection is:

[0019]

[0020] in: It is the difference between the terminal voltage and the grid connection point voltage; are the terminal voltage and grid connection point voltage vectors respectively; U mt , U ms are the amplitudes of the terminal voltage and the grid-connected point voltage vector respectively; ω t ,ω s are generator frequency and system frequency respectively; φ t ,φ s They are the phases of the machine-end voltage and the grid-connected point voltage respectively.

[0021] After the parallel diesel generator completes synchronous closing, the phase and frequency are consistent with the grid-connected units. Next, the output of the paralleled units needs to be gradually increased to bear the load, and the grid-connected units need to gradually reduce the output. The power oscillation of the above adjustment process can be reduced by using the power balancing model. The power distribution expression is as follows:

[0022]

[0026] Where: PN i is the rated power of each diesel engine; C i (1 is closed, 0 is open) is the synchronous closing status of each diesel engine.

[0024] Preferably, a busbar circuit breaker DL3 is installed between the two power supply lines of the power grid. When only one power grid cannot supply normally, the other power grid carries two loads through the busbar circuit breaker DL3. At this time, the diesel generator set can still transmit electricity to the power grid through the power grid line to participate in demand response. Preferably, the diesel generator participating in demand response in S3 further comprises the following steps:

[0025] Preferably, the diesel generators participate in demand response when the power consumption peaks or the grid is overloaded, which requires the diesel generators to quickly complete the parallel connection and grid connection, access the grid in the shortest time, and reduce the burden on the grid.

[0026] Preferably, when at least one of the two power grids is supplying normally and the diesel generator set on line A participates in demand response, the diesel generator on line A starts with low power to start quasi-synchronous parallel operation. When the parallel operation is completed, the switch DL8 is closed. When it is determined that the quasi-synchronous grid connection conditions are met, the switch DL6 is closed to achieve grid connection. The diesel generator on line A carries part of the load to reduce the load power supply demand during the peak period of power consumption of the power grid. When the power supply of the power grid returns to normal, the diesel generators exit operation in turn. When all the diesel generators exit operation, the switches DL8 and DL6 are disconnected to achieve the removal of the diesel generators. In this way, the diesel generator sets are connected to the power grid to participate in demand response.

[0027] Preferably, when at least one of the two power grids is supplying normally and the diesel generator set on line B participates in demand response, the diesel generator on line B starts with low power to start quasi-synchronous parallel operation. When the parallel operation is completed, switch DL9 is closed. When it is determined that the quasi-synchronous grid connection conditions are met, switch DL7 is closed to achieve grid connection. The diesel generator on line B carries part of the load to reduce the load power supply demand during the peak period of power consumption of the power grid. When the power supply of the power grid returns to normal, the diesel generators exit operation in turn. When all the diesel generators exit operation, switches DL9 and DL7 are disconnected to achieve the removal of the diesel generators. In this way, the diesel generator sets are connected to the power grid to participate in demand response.

[0028] Preferably, when the power grid is in normal supply and the diesel generator is not involved in demand response, the diesel generator set in the data center is only used as a backup power source. Once a power failure occurs, the diesel generator needs to be connected immediately to ensure stable power supply in the data center.

[0029] Preferably, when both power grids cannot supply power normally, the data center loses power, and the two diesel generator sets cannot participate in demand response. The incoming line switches DL8 and DL6 of the diesel generator set on line A are closed, and the incoming line switches DL9 and DL7 of the diesel generator set on line B are closed, and the diesel generator sets are put into use as emergency backup power supplies.

[0030] The present invention provides a grid-connected control method for a data center diesel generator participating in demand response. By modifying the original topology model, when at least one grid is normally supplied, the diesel generator set transmits electric energy to the grid through the grid line to participate in demand response. And by controlling the incoming switch of the diesel generator set, the diesel generator set can work and participate in demand response mode and emergency power supply mode. It effectively solves the technical problems of the inadaptability of the multi-unit topology model and the confusion of the switch control logic when the data center diesel generator participates in demand response.

[0031] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the logic truth table of each circuit breaker after transformation

[0033] Figure 2 This is the topology model diagram before transformation

[0034] Figure 3 This is the topological model diagram after transformation

[0035] Figure 4 Schematic diagram of diesel generators participating in demand response

[0036] Figure 5 This is a diagram of a diesel generator as an emergency backup power supply.

[0037] Figure 6 Schematic diagram of the steps for connecting a diesel generator to the grid

[0038] Figure 7 This is a schematic diagram of the power regulation principle of a diesel generator set.

[0039] Figure 8 Schematic diagram of diesel generator sets participating in demand response strategy

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor. DETAILED DESCRIPTION

[0041] The present invention proposes a grid-connected control method for a data center diesel generator participating in demand response, which is used to solve the technical problems of topology model inadaptability and switch control logic confusion when the data center diesel generator participates in demand response.

[0042] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0043] The technical solution of the present invention is described in detail below with reference to the accompanying drawings. Figure 2 The data center topology model with two power grids as shown, in which mechanical interlocks and electrical interlocks are set between DL2 and DL3, and between DL and DL. The diesel generator inlet switch will only be closed when the power grid fails. The diesel generator is only used as an emergency power supply and cannot participate in demand response. It cannot meet the necessary requirements of connecting the diesel generator in parallel with the power grid when participating in demand response.

[0044] By connecting the diesel generator set in the data center to the power grid through ATS and removing the mechanical interlock and electrical interlock between DL2 and DL3 in the original topology model, the modified topology model is as follows: Figure 3 As shown, the diesel generator set can transmit electric energy to the grid through the grid lines when the grid is normally supplied, and participate in demand response.

[0045] In order for the diesel generator sets in the data center to participate in demand response, in addition to modifying the original topology model, they also need to be synchronized and connected to the grid. This can only be done when the conditions for quasi-synchronous parallel connection and grid connection are met. Otherwise, a large impact current will be generated and affect the power grid.

[0046] When performing synchronous parallel operation and grid connection operation, in order to avoid large impact current during the parallel operation, the following three conditions should be met between the generator set to be connected and the operating unit:

[0047] U1=U2 (9)

[0048] f1=f2 (10)

[0049]

[0050] It is almost impossible to meet the three conditions of parallel connection and grid connection at the same time. That is to say, it is impossible for there to be no impact current in the system when parallel connection and grid connection are carried out. Long-term practice has proved that the following three conditions can be met when the generator sets are actually paralleled and grid connected:

[0051]

[0052] Δf=|f2-f1|≤0.5Hz (13)

[0053]

[0054] Among them, U1 and U2 are the voltage value of the unit to be connected and the voltage value of the running unit respectively, and f1 and f2 are the frequency of the unit to be connected and the frequency of the running unit respectively. They are the voltage phase of the units to be connected and the voltage phase of the units on the grid.

[0055] The ideal grid-connected condition for diesel generator sets is that the two vectors of the generator end and the system side bus voltage completely coincide and rotate synchronously. The voltage difference between the generator end and the system side before grid connection is:

[0056]

[0057] in: It is the difference between the terminal voltage and the grid connection point voltage; are the terminal voltage and grid connection point voltage vectors respectively; U mt , U ms are the amplitudes of the terminal voltage and the grid-connected point voltage vector respectively; ω t ,ω s are generator frequency and system frequency respectively; φ t ,φ s They are the phases of the machine-end voltage and the grid-connected point voltage respectively.

[0058] After the parallel diesel generator completes synchronous closing, the phase and frequency are consistent with the grid-connected units. Next, the output of the paralleled units needs to be gradually increased to bear the load, and the grid-connected units need to gradually reduce the output. The power balancing model can reduce the power oscillation in the above adjustment process. The diesel generator is connected to the grid at low power and the power distribution is achieved through the power ramp of the diesel generator.

[0059]

[0060] Where: PN i is the rated power of each diesel engine; C i (1 is closed, 0 is open) is the synchronous closing status of each diesel engine.

[0061] like Figure 3 As shown, a bus tie breaker DL3 is installed between the two power supply lines of the power grid. When only one power grid cannot supply normally, the other power grid carries two loads through the bus tie breaker DL3. At this time, the diesel generator set can still transmit electric energy to the power grid through the power grid line to participate in the demand response requirements.

[0062] The modified switch control logic truth table is as follows: Figure 1 As shown, when at least one of the two power grids is supplying normally and the diesel generator set on line A participates in demand response, the diesel generator on line A starts with low power to start quasi-synchronous parallel operation. When the parallel operation is completed, switch DL8 is closed. When it is determined that the quasi-synchronous grid connection conditions are met, switch DL6 is closed to achieve grid connection. The diesel generator carries part of the load to reduce the load power supply demand during the peak period of power consumption of the power grid. When the power supply of the power grid returns to normal, the diesel generators exit operation in turn. When all the diesel generators exit operation, switches DL8 and DL6 are disconnected to achieve the removal of the diesel generators. In this way, the diesel generator sets are connected to the power grid to participate in demand response.

[0063] When at least one of the two power grids is supplying normally and the diesel generator set on line B participates in demand response, the diesel generator on line B starts with low power to start quasi-synchronous parallel operation. When the parallel operation is completed, switch DL9 is closed. When it is determined that the quasi-synchronous grid connection conditions are met, switch DL7 is closed to achieve grid connection. The diesel generator on line B carries part of the load to reduce the load power supply demand during the peak period of power consumption of the power grid. When the power supply of the power grid returns to normal, the diesel generators will exit operation in turn. When all the diesel generators exit operation, switches DL9 and DL7 are disconnected to achieve the removal of the diesel generators. In this way, the diesel generator sets are connected to the power grid to participate in demand response.

[0064] Diesel generators participate in demand response generally when electricity consumption peaks or the grid is overloaded, which requires diesel generators to quickly complete parallel connection and grid connection, access the grid in the shortest time possible, and reduce the burden on the grid.

[0065] like Figure 4 As shown in the figure, when both power grids cannot supply power normally, the data center loses power, and the two diesel generator sets cannot participate in demand response. The diesel generators need to be connected immediately to ensure the stability of the power supply inside the data center. The incoming switches DL6 and DL8 of the diesel generator set on line A are closed, and the incoming switches DL5 and DL7 of the diesel generator set on line B are closed, and the diesel generator sets are put into use as emergency backup power sources. When the power grid is at its peak, the diesel generator starts with a small power and starts quasi-synchronous parallel operation. When the parallel operation is completed, the switch DL8 is closed. When it is determined that the quasi-synchronous grid connection conditions are met, the switch DL6 is closed to achieve grid connection. When the power grid is restored, the diesel generators exit operation in turn. When all the diesel generators exit operation, the switches DL8 and DL6 are opened to achieve the removal of the diesel generators. In this way, the diesel generator sets are connected to the grid to participate in demand response.

[0066] In order to verify the effectiveness and profitability of the method of the patent application of the present invention, a specific example is used to verify the method.

[0067] by Figure 1As shown in the figure, when at least one of the two power grids is supplying normally and the diesel generator set on line A participates in demand response, the diesel generator on line A starts with low power to start quasi-synchronous parallel operation. When the parallel operation is completed, switch DL8 is closed. When it is determined that the quasi-synchronous grid connection conditions are met, switch DL6 is closed to achieve grid connection. At this time, the diesel generator of the data center is connected to the grid to participate in demand response, reducing the load power supply demand during the peak period of power consumption of the grid. The data center can calculate the cost profit based on the specific power generation of the diesel generator participating in demand response. When the power supply of the grid returns to normal, the diesel generators will exit operation in turn. When all the diesel generators are out of operation, switches DL8 and DL6 are disconnected to achieve the removal of the diesel generators. In this way, the diesel generator sets are connected to the grid to participate in demand response.

[0068] The construction of Shanghai's power peak-shaving auxiliary service market will help tap the peak-shaving capacity of power generators in and outside the city, connect the East China power peak-shaving auxiliary service market, better solve the contradiction of Shanghai power grid's low-peak peak-shaving, improve Shanghai power grid's ability to absorb clean energy, and reasonably compensate power generation companies that contribute to Shanghai power grid's peak-shaving. The current upper limit of the declared price for Shanghai's medium- and long-term peak-shaving auxiliary service market is 2,400 yuan / MWh; the upper limit of the declared price for temporary peak-shaving services is 6,000 yuan / MWh.

[0069] Take a data center as an example. It is equipped with 10 2MW diesel generators. The diesel generator sets use 80% of the main power to generate electricity. Obviously, the full power of the Youfu diesel generator has the opportunity to supply all of it to the grid. 10 2MW diesel generators, with 80% of the main power as the continuous power calculation, take a continuous response of one hour as an example, the data center can generate 16,000 degrees of electricity, and the following profit analysis is conducted.

[0070] On July 13, 2023, 15:00-16:00, Shanghai released temporary peak load demand. Assuming that the data center successfully participated and won the bid for the maximum power generation capacity, the following calculations were made:

[0071] The data center won the bid with the maximum power generation and responded effectively in the actual response. During the response period, the power grid was in a normal load period, and the electricity price was 0.61￥ / kW. The difference in electricity charges caused by the diesel generator carrying load and no longer needing to purchase electricity from the power grid should be calculated in the revenue. The comprehensive profit is 73,056 yuan. If multiple data centers participate in demand response at multiple times, the profit prospects will be even broader.

[0072] The present invention is based on the diesel generator grid-connected logic transformation technology. By transforming the original topology model, the necessary requirement of the diesel generator in parallel with the power grid when participating in demand response is met. And by controlling the incoming line switch of the diesel generator set, the diesel generator set can work and participate in the demand response mode and emergency power supply mode. It effectively solves the technical problems of multi-unit paralleling and grid connection difficulties, unsuitable topology models and chaotic switch control logic when the data center diesel generator participates in demand response.

Claims

1. A method for grid-connected control of a data center diesel generator participating in demand response, characterized in that: Topology model transformation: In the original two-way power supply topology model, the diesel generator inlet switch is closed only when the power grid fails. The diesel generator is only used as an emergency power supply and cannot participate in demand response. It cannot meet the necessary requirements of connecting the diesel generator in parallel with the power grid when participating in demand response; Quasi-synchronous parallel connection and grid connection: When diesel generators participate in demand response, they need to be synchronized and connected to the grid. This can only be done when the conditions for quasi-synchronous parallel connection and grid connection are met; Participation in demand response: After completing quasi-synchronous parallel operation, the diesel generator transmits electricity to the grid through the grid lines, and increases the transmission capacity by increasing the number of operating units, enabling the diesel generator sets to participate in demand response.

2. The method for grid-connected control of diesel generators participating in demand response according to claim 1, characterized in that: The specific steps of the control method are as follows: (1) In the original two-way mains power supply topology model, the diesel generator inlet switch is closed only when the mains fails. By removing the electrical and mechanical interlocks between the switches of the ATS grid-connected device, the diesel generator can transmit electricity to the grid through the ATS grid-connected device when the grid is normally supplied, and participate in demand response; (2) When the power grid is at its peak, start the data center diesel generator at low power, complete the quasi-synchronous parallel operation of the diesel generator, and close the switch at the diesel generator outlet; (3) Monitor the voltage, frequency and phase at the diesel generator set outlet and the grid. When the quasi-synchronous grid-connected condition is met, that is, when the two vectors of the diesel generator end and the grid side voltage basically coincide and rotate synchronously, close the ATS grid-connected device switch at the diesel generator set outlet; (4) Gradually increase the output of the diesel generator and realize power distribution by ramping the diesel generator power until the diesel generator outputs stably; (5) Determine whether normal power supply has been restored on the grid side. If so, disconnect the diesel generator output switch and the ATS grid-connected device switch to remove the diesel generator from demand response.

3. The method for grid-connected control of diesel generators participating in demand response according to claim 2 is characterized in that: In the step (3), when the voltage difference ΔU between the diesel generator set outlet and the grid connection point is less than 10%U (U is the grid connection point voltage), the frequency difference Δf is less than 0.5Hz, and the phase difference δ is less than 2°, it is judged that the quasi-synchronous grid connection condition is met.

4. The method for grid-connected control of diesel generators participating in demand response according to claim 2 is characterized in that: The calculation expression of the power distribution of the diesel generator after grid connection is as follows: Where: PN i is the rated power of each diesel engine; C i (1 is closed, 0 is open) is the synchronous closing status of each diesel engine.

5. The method for grid-connected control of diesel generators participating in demand response according to claim 2, characterized in that: The voltage difference calculation expression between the diesel generator end and the grid side is as follows: in: It is the difference between the voltage of the diesel generator set and the voltage at the grid connection point; are the voltage vectors of the diesel generator set and the grid connection point respectively; U mt , U ms are the amplitudes of the diesel generator voltage and the grid-connected point voltage vector respectively; ω t ,ω s are the frequency of the diesel generator set and the frequency of the grid connection point respectively; φ t ,φ s They are the phases of the diesel generator set voltage and the grid connection point voltage respectively.

6. The method for grid-connected control of diesel generators participating in demand response according to claim 1, characterized in that: When the diesel generator participates in demand response in different scenarios, a truth table of the switch logic in the different scenarios is generated, and the diesel generator participates in and exits demand response in different scenarios according to the preset switch opening and closing timing.

7. The diesel generator according to claim 6 participates in demand response, so that the idle power generation equipment can participate in market competition.

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