A grid dispatching method considering the active feasible region of the coupled system of renewable energy and thermal power

Abstract

The present invention relates to the technical field of electric power systems, and in particular to a grid dispatching method taking into account the active feasible domain of a coupling system of new energy and thermal power, comprising the following steps: S1, according to the operating status and operating data of the thermal power unit, analyzing the climbing rate of the thermal power unit under different operating conditions, obtaining the step-type climbing characteristics of the thermal power unit, and deriving the general expression of the power constraint of the thermal power unit taking into account the deep peak regulation; S2, according to the general expression of the power constraint of the thermal power unit, calculating the active feasible domain of the adjacent moments of any thermal power unit with determined unit parameters and dispatching time scale; S3, determining the active feasible domain of the adjacent moments of the new energy according to the rapid response characteristics of the new energy power generation. This method can reduce the difficulty of regulating the active power of the power grid system, help solve the problem that the integrated dispatching of the whole network is difficult to handle a large number of generating units, and can better play the supporting role of the coupling system to the upper power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power systems, and in particular to a power grid dispatching method taking into account the active feasible domain of a new energy and thermal power coupling system. Background Art

[0002] As an important part of building a new power system, new energy is an important means to achieve decarbonization of the power industry. my country is rich in new energy resources such as wind energy, which are suitable for large-scale development and utilization. As of the end of June 2020, my country's wind power installed capacity has reached 217 million kW, and photovoltaic power generation installed capacity has reached 204 million kW. However, although new energy has large reserves and wide distribution, it has anti-peak characteristics such as randomness, volatility, and uneven distribution in time and space. With the long-term rapid growth of new energy installed capacity, the power system faces challenges in achieving high-level new energy consumption. Due to its unique geographical factors, the proportion of flexible power sources such as gas power and hydropower in the northern region of my country is insufficient, and the flexibility demand for new energy consumption mainly relies on thermal power.

[0003] The coupling system of thermal power and renewable energy, which is integrated into a unified operating entity through the same grid connection point, is common in my country's northern power grid. The determination of its active power regulation capability is the key to the overall participation of the coupling system in the operation of the power grid. At present, the two are usually regarded as independent operating entities, and their operation control is essentially no different from the multi-power dispatching operation of the large power grid. The renewable energy and thermal power units in the coupling system send their own active feasible domains to the superior power grid respectively. While characterizing the active feasible domain, it takes into account all the output conditions of each internal power source and includes all possibilities. The points within the active feasible domain can cooperate with the dispatch of the superior power grid. When the power grid system (i.e., the superior power grid) performs active power regulation, it uses the active feasible domains of each renewable energy and thermal power unit as reference data for regulation. However, this regulation method has the following problems:

[0004] First, when the power grid system adjusts the active power, it is necessary to consider the active feasible domain of each renewable energy and thermal power unit, and then send the adjustment target to each renewable energy and thermal power unit respectively. There are many objects that need to be considered in the process, which is inefficient and difficult to adjust.

[0005] Second, in the prior art, the research on the active feasible domain uploaded all focuses on using different models and algorithms to determine the boundaries of the active power of key nodes and lines in the power system, but does not consider the direct impact of the active power at the previous moment on the active power boundary at the current moment, ignores the temporal state dependence of the active power regulation capability of the multi-power system, and is difficult to accurately describe the dynamic characteristics of the active regulation of the multi-power system. When the power grid system formulates regulation targets based on such an active feasible domain, there will be a situation where the regulation object (new energy or thermal power unit) cannot complete the regulation task within the specified time limit (such as within half an hour), and the desired regulation effect cannot be achieved when the time limit is reached. As a result, the controllability of the active power regulation of the power grid system is not high.

[0006] Therefore, how to reduce the difficulty of regulating the active power of the power grid system and improve the controllability of the regulation has become a problem that needs to be solved urgently. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a power grid dispatching method taking into account the active feasible domain of the renewable energy and thermal power coupling system, which can reduce the difficulty of regulating the active power of the power grid system and improve the controllability of the regulation.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] The grid dispatching method taking into account the active feasible region of the coupling system of renewable energy and thermal power generation is used for the coupling system of renewable energy and thermal power generation units, and includes the following steps:

[0010] S1. According to the operating status and operating data of the thermal power unit, the climbing rate of the thermal power unit under different operating conditions is analyzed, the step-type climbing characteristics of the thermal power unit are obtained, and the general expression of the power constraint of the thermal power unit taking into account the deep peak regulation is derived;

[0011] S2. According to the general expression of power constraint of thermal power units, calculate the feasible domain of active power at adjacent moments of any thermal power unit with determined unit parameters and scheduling time scale;

[0012] S3. According to the rapid response characteristics of renewable energy power generation, determine the feasible domain of renewable energy active power at adjacent moments;

[0013] S4. According to the actual coupling scenario of the coupling system, define the basic operation of the feasible domain set and construct the feasible domain of the active power of the coupling system of new energy and thermal power at adjacent moments;

[0014] S5. Report the feasible domain of active power at adjacent moments of the constructed new energy and thermal power coupling system to the upper-level power grid, and the upper-level power grid can refer to the feasible domain of active power at adjacent moments of the constructed new energy and thermal power coupling system to carry out operation dispatch of the power grid system.

[0015] Preferably, in S4, the active feasible region of the coupled system at adjacent moments is:

[0016]

[0017] in,

[0018] P max is the capacity of the system, P min is the minimum active power allowed by the system, P t is the active power of the system at the current moment, P t-1 is the active power of the system at the last moment, R n is the system ramp rate and system capacity P max The ratio of , Δt is the scheduling time.

[0019] Preferably, in S1, the step-type ramp-up constraint of the thermal power unit is:

[0020]

[0021] Among them, R1 is the corresponding ramp rate and unit capacity of the thermal power unit under the RPR state. R2 is the ratio of the corresponding ramp rate and unit capacity of the thermal power unit under the DPR state. R3 is the corresponding ramp rate and unit capacity of the thermal power unit under DPRO state. The ratio of; Among them, RPR state is the basic peak-shaving state; DPR state is the deep peak-shaving state without oil injection; DPRO state is the deep peak-shaving state with oil injection; P t TH is the active power of the thermal power unit at the current moment; is the active power of the thermal power unit at the last moment; a1 is the minimum load value of the thermal power unit under the RPR state and a2 is the ratio of the minimum load of the thermal power unit under the DPR state to a3 is the ratio of the minimum load of the thermal power unit under the DPRO state to ratio.

[0022] Preferably, in S1, the output constraint of the thermal power unit is also satisfied:

[0023] Preferably, in S1, the general expression of the power constraint of the thermal power unit taking into account the deep peak regulation is:

[0024]

[0025] Among them, U t represents the state of the unit at time t, U t =1 means the unit is in operation, U t=0 means the unit is in shutdown state.

[0026] Preferably, in S1, if the thermal power unit parameters meet but

[0027]

[0028]

[0029]

[0030]

[0031] Merge into:

[0032]

[0033]

[0034] Preferably, in S3, the feasible domain of the active power of new energy at adjacent moments is:

[0035]

[0036] and

[0037] in, is the maximum output power of the new energy in the coupling system at time t-1, is the maximum output power of the new energy in the coupling system at time t, P t r is the power generated by the new energy at the current moment, is the power generation of the new energy at time t-1.

[0038] Preferably, in S4, the active feasible region of a single thermal power plant and new energy coupling system is:

[0039]

[0040]

[0041] Among them, Ω CS' It is the feasible domain when the thermal power unit always keeps running; It is the feasible domain when the thermal power units are never put into operation; It is the feasible domain when the thermal power unit is in shutdown state at time t-1, but completes startup at time t; is the feasible domain when the thermal power unit is in operation at time t-1, but the thermal power unit is shut down at time t; Ω r for and The union of .

[0042] Preferably,

[0043]

[0044]

[0045]

[0046] in, The ratio of the lower limit of the active power allowed to start a thermal power unit to the unit capacity; It is the ratio of the upper limit of the active power allowed to start the thermal power unit to the unit capacity; It is the ratio of the minimum power allowed for shutdown to the unit capacity; It is the ratio of the maximum power allowed for shutdown to the unit capacity.

[0047] Preferably,

[0048]

[0049]

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. This application utilizes the characteristics of the thermal power and new energy coupling system that are coupled and integrated into a unified operating entity through the same grid connection point, packages the active feasible domains of new energy and thermal power units in the same coupling system, and reports it to the superior power grid after an overall characterization of the active feasible domain of the coupling system. In this way, when the power grid system dispatches active power, it no longer needs to refer to the active feasible domain of each thermal power unit and new energy, but only needs to refer to the active feasible domain of each coupling system. This scheduling method can greatly reduce the number of dispatch objects of the superior power grid, better play the supporting role of the coupling system to the superior power grid, thereby improving the scheduling efficiency of the active power of the power grid system and reducing the difficulty of regulation.

[0052] 2. This method fully considers the temporal state dependence of the active power regulation capability of the multi-power system. When constructing the active feasible domain, not only the correlation between the output power that can be achieved by the multi-power coupling system at the current moment and the parameters of the unit or equipment itself and the scheduling time scale is considered, but also its correlation with the output power at the previous moment is considered. After determining the active feasible domains of the new energy and thermal power units in the coupling system respectively, the active feasible domain of the coupling system at adjacent moments is constructed.

[0053] When the method is used to dispatch the active power of the power grid system, the information received by the power grid system is the active feasible domain of each coupled system at adjacent moments. When dispatching with these adjacent active feasible domains as reference, the dispatching targets are basically within the adjacent active feasible domains. When each coupled system is specifically adjusted, it must be able to complete the adjustment target within the specified time limit (i.e. adjacent moments, such as half an hour). This greatly improves the controllability of the active power dispatch of the power grid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to make the purpose, technical solution and advantages of the invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0055] Figure 1 is a flow chart in an embodiment;

[0056] Figure 2 It is a structural schematic diagram of the new energy and thermal power coupling system in the embodiment;

[0057] Figure 3 This is a schematic diagram of the relationship between the load and the ramp rate of a thermal power unit;

[0058] Figure 4 This is a schematic diagram of the feasible region of active power of a single thermal power unit at adjacent moments;

[0059] Figure 5 Schematic diagram of the feasible domain of active power of new energy at adjacent moments in the embodiment;

[0060] Figure 6 It is the overall schematic diagram of the active feasible region of the coupled system at adjacent moments;

[0061] Figure 7 Schematic diagram of the feasible domain of active power at adjacent moments when thermal power units are coupled with renewable energy. DETAILED DESCRIPTION

[0062] The following is a further detailed description through specific implementation methods:

[0063] Example:

[0064] like Figure 1 , Figure 2 As shown, this embodiment discloses a power grid dispatching method taking into account the active feasible domain of the coupling system of renewable energy and thermal power, which is used for the coupling system of renewable energy and thermal power units, and includes the following steps:

[0065] S1. According to the operating status and operating data of the thermal power unit, the climbing rate of the thermal power unit under different operating conditions is analyzed, the step-type climbing characteristics of the thermal power unit are obtained, and the general expression of the power constraint of the thermal power unit taking into account the deep peak regulation is derived.

[0066] Specifically, the step-by-step ramping constraints of thermal power units are:

[0067]

[0068] Among them, R1 is the corresponding ramp rate and unit capacity of the thermal power unit under the RPR state. R2 is the ratio of the corresponding ramp rate and unit capacity of the thermal power unit under the DPR state. R3 is the corresponding ramp rate and unit capacity of the thermal power unit under DPRO state. The ratio of; Among them, RPR state is the basic peak-shaving state; DPR state is the deep peak-shaving state without oil injection; DPRO state is the deep peak-shaving state with oil injection; P t TH is the active power of the thermal power unit at the current moment; is the active power of the thermal power unit at the last moment; a1 is the minimum load value of the thermal power unit under the RPR state and a2 is the ratio of the minimum load of the thermal power unit under the DPR state to a3 is the ratio of the minimum load of the thermal power unit under the DPRO state to The relationship between the load and the ramp rate of a thermal power unit is as follows: Figure 3 shown.

[0069] It also meets the output constraints of thermal power units: Among them, P t is the active power of the system at the current moment.

[0070] The general expression of power constraint of thermal power units taking into account deep peak regulation is:

[0071]

[0072] Among them, U t represents the state of the unit at time t, U t =1 means the unit is in operation, U t =0 means the unit is in shutdown state; Δt is the scheduling time.

[0073] In specific implementation, if the thermal power unit parameters meet but

[0074]

[0075]

[0076]

[0077]

[0078] Merge into:

[0079]

[0080]

[0081] S2. According to the general expression of power constraint of thermal power units, calculate the feasible domain of active power at adjacent moments of any thermal power unit with determined unit parameters and scheduling time scale.

[0082] For ease of understanding, taking a local power grid thermal power unit as an example, the ramp rates of the unit in the RPR state, DPR state, and DPRO state are and The power ranges of the three states are: and That is, the corresponding climbing rates R1, R2 and R3 of the thermal power unit in the three states are 1.5%, 1% and 0.5% respectively, and a1, a2 and a3 are 0.5, 0.4 and 0.3 respectively. Under this condition, the thermal power unit parameters and the scheduling period Δt=30min given in this embodiment are used to determine the feasible domain of the active power of the thermal power unit at adjacent moments. The feasible domain determination method is applicable to any thermal power unit parameters and scheduling time scale. At this time, the feasible domain of the active power of the thermal power unit at adjacent moments is:

[0083]

[0084] in,

[0085] The schematic diagram of the feasible domain of active power of a single thermal power unit at adjacent times is as follows: Figure 4 shown.

[0086] S3. According to the rapid response characteristics of renewable energy power generation, determine the feasible domain of renewable energy active power at adjacent moments.

[0087] In addition to thermal power units, the coupled system also needs to consider the output of renewable energy. Most current studies regard wind and solar as non-optimizable variables, which are difficult to provide active regulation margin for the power grid. In this study, renewable energy is regarded as a flexible resource, which can provide a downward adjustment margin for the system by abandoning wind and solar power, or provide an upward adjustment margin for the system by reducing power in advance. is the maximum output power of the new energy in the coupling system at time t-1, is the maximum output power of the new energy in the coupling system at time t, P t r is the power generated by the new energy at the current moment. Since new energy has the ability to adjust power quickly, its power adjustment time can be ignored compared with the dispatch time scale. Therefore, when considering the active power of new energy, we have:

[0088]

[0089] The feasible domain of new energy active power at adjacent moments is:

[0090]

[0091] According to the formula of the feasible domain of active power of new energy at adjacent moments, the feasible domain of active power of new energy at adjacent moments in the coordinate plane is a region with a length and a width of and A rectangular area such as Figure 5 It should be noted that for a given new energy station, and It is directly determined by the size of the primary energy at the corresponding moment. The fluctuation of primary energy at different moments will change Figure 5 The side length of the middle rectangle.

[0092] S4. According to the actual coupling scenario of the coupled system, the basic operations of the feasible domain set are defined to construct the active feasible domain of the coupled system of renewable energy and thermal power at adjacent moments.

[0093] The output power that can be achieved by the multi-power coupling system (mainly the renewable energy and thermal power coupling system in this paper) at the current moment is not only affected by the parameters of the unit or equipment itself and the scheduling time scale, but also closely related to the output power at the previous moment.

[0094] Assume the capacity of the system is P max , the minimum active power allowed by the system is P min , the system active power at the current moment is P t , the active power of the system at the last moment is P t-1 , system ramp rate and system capacity P max The ratio is R n , the scheduling time scale is Δt, then the power of the system satisfies the ramp rate constraint:

[0095] P t-1 -R n P max Δt≤P t ≤P t-1 +R n P max Δt

[0096] The active output of the system at any time meets the system output constraints:

[0097] P min ≤P t ≤P max

[0098] Then the feasible domain of the system's active power at adjacent moments is:

[0099] The specific instructions are as follows Figure 6 shown.

[0100] The active feasible domain of a single thermal power plant and new energy coupling system is:

[0101]

[0102]

[0103] Among them, Ω CS' It is the feasible domain when the thermal power unit always keeps running; It is the feasible domain when the thermal power units are never put into operation; It is the feasible domain when the thermal power unit is in shutdown state at time t-1, but completes startup at time t; is the feasible domain when the thermal power unit is in operation at time t-1, but the thermal power unit is shut down at time t; Ω r for and The feasible domain of the active power of thermal power units coupled with renewable energy at adjacent moments is as follows: Figure 7 shown.

[0104]

[0105]

[0106]

[0107] in, The ratio of the lower limit of the active power allowed to start a thermal power unit to the unit capacity; It is the ratio of the upper limit of the active power allowed to start the thermal power unit to the unit capacity; It is the ratio of the minimum power allowed for shutdown to the unit capacity; It is the ratio of the maximum power allowed for shutdown to the unit capacity.

[0108]

[0109]

[0110] S5. Report the feasible domain of active power at adjacent moments of the constructed new energy and thermal power coupling system to the upper-level power grid, and the upper-level power grid performs operation dispatch of the power grid system with reference to the feasible domain of active power at adjacent moments of the constructed new energy and thermal power coupling system.

[0111] There are few studies on the coupling of renewable energy and thermal power at the same grid connection point, but such coupling scenarios are common in my country's northern power grid. Taking Liaoning Power Grid as an example, the installed capacity of renewable energy and thermal power with the potential for coupling at the same grid connection point accounts for more than 42%. This method utilizes the characteristics of the thermal power and renewable energy coupling system that is integrated into a unified operating entity through coupling at the same grid connection point, packages the active feasible domains of renewable energy and thermal power units in the same coupling system, and reports to the upper-level power grid after an overall characterization of the active feasible domain of the coupling system. In this way, when the power grid system is dispatching active power, it no longer needs to refer to the active feasible domain of each thermal power unit and renewable energy, but only needs to refer to the active feasible domain of each coupling system. This dispatching method can greatly reduce the number of dispatching objects of the upper-level power grid, better play the supporting role of the coupling system to the upper-level power grid, thereby improving the dispatching efficiency of the active power of the power grid system and reducing the difficulty of regulation.

[0112] In addition, this method fully considers the time-series state dependency of the active power regulation capability of the multi-power system. When constructing the active feasible domain, not only the correlation between the output power that can be achieved by the multi-power coupling system at the current moment and the parameters of the unit or equipment itself and the scheduling time scale is considered, but also the correlation with the output power at the previous moment is considered. After determining the active feasible domains of the new energy and thermal power units in the coupling system respectively, the active feasible domains of the coupling system at adjacent moments are constructed. When using this method to dispatch the active power of the power grid system, the information received by the power grid system is the active feasible domains of the adjacent moments of each coupling system. When scheduling with these adjacent moments active feasible domains as a reference, the scheduling targets are basically within the adjacent moments active feasible domains. When each coupling system is specifically adjusted, it must be able to complete the adjustment target within the specified time limit (i.e. adjacent moments, such as half an hour). Thereby greatly improving the controllability of the active power scheduling of the power grid system.

[0113] The active power dispatching method of the power grid system in this method is conducive to fully tapping the coordinated dispatching potential of new energy and thermal power, and promoting the coordinated development of new energy and thermal power on a large scale. The characterization of the active feasible domain of the coupled system at adjacent moments is conducive to better playing the supporting role of the coupled system to the upper power grid, which is of great significance for solving the problem that the integrated dispatching of the whole network is difficult to handle a large number of generating units, and for the overall participation of the coupled system in the grid dispatching and peak load auxiliary services.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A power grid dispatching method taking into account the active feasible region of the coupling system of new energy and thermal power, characterized in that: The coupling system for new energy and thermal power generation units includes the following steps: S1. According to the operating status and operating data of the thermal power unit, the climbing rate of the thermal power unit under different operating conditions is analyzed, the step-type climbing characteristics of the thermal power unit are obtained, and the general expression of the power constraint of the thermal power unit taking into account the deep peak regulation is derived; S2. According to the general expression of power constraint of thermal power units, calculate the feasible domain of active power at adjacent moments of any thermal power unit with determined unit parameters and scheduling time scale; S3. According to the rapid response characteristics of renewable energy power generation, determine the feasible domain of renewable energy active power at adjacent moments; S4. According to the actual coupling scenario of the coupling system, define the basic operation of the feasible domain set and construct the feasible domain of the active power of the coupling system of new energy and thermal power at adjacent moments; S5. Report the active feasible domain of the constructed new energy and thermal power coupling system at adjacent moments to the upper-level power grid, and the upper-level power grid can refer to the active feasible domain of the constructed new energy and thermal power coupling system at adjacent moments to perform operation dispatch of the power grid system; Among them, in S4, the active feasible domain of a single thermal power plant and new energy coupling system is: Among them, P t is the active power of the system at the current moment; P t-1 is the active power of the system at the previous moment; is the unit capacity; Ω CS ' is the feasible domain when the thermal power unit always keeps running; It is the feasible domain when the thermal power units are never put into operation; It is the feasible domain when the thermal power unit is in shutdown state at time t-1, but completes startup at time t; is the feasible domain when the thermal power unit is in operation at time t-1, but the thermal power unit is shut down at time t; Ω r for and The union of; in, The ratio of the lower limit of the active power allowed to start a thermal power unit to the unit capacity; It is the ratio of the upper limit of the active power allowed to start the thermal power unit to the unit capacity; It is the ratio of the minimum power allowed for shutdown to the unit capacity; It is the ratio of the maximum power allowed for shutdown to the unit capacity; is the maximum output power of the new energy in the coupling system at time t; is the maximum output power of the new energy in the coupling system at time t-1.

2. The power grid dispatching method taking into account the active feasible region of the coupling system of new energy and thermal power as claimed in claim 1 is characterized by: In S4, the feasible domain of active power of the coupled system at adjacent moments is: in, P max is the capacity of the system, P min is the minimum active power allowed by the system, P t is the active power of the system at the current moment, P t-1 is the active power of the system at the last moment, R n is the system ramp rate and system capacity P max The ratio of , Δt is the scheduling time.

3. The power grid dispatching method taking into account the active feasible region of the coupling system of new energy and thermal power as claimed in claim 2 is characterized by: In S1, the step-by-step ramping constraint of the thermal power unit is: Among them, R1 is the corresponding ramp rate and unit capacity of the thermal power unit under the RPR state. R2 is the ratio of the corresponding ramp rate and unit capacity of the thermal power unit under the DPR state. R3 is the corresponding ramp rate and unit capacity of the thermal power unit under DPRO state. The ratio of; Among them, RPR state is the basic peak-shaving state; DPR state is the deep peak-shaving state without oil injection; DPRO state is the deep peak-shaving state with oil injection; P t TH is the active power of the thermal power unit at the current moment; is the active power of the thermal power unit at the last moment; a1 is the minimum load value of the thermal power unit under the RPR state and a2 is the ratio of the minimum load of the thermal power unit under the DPR state to a3 is the ratio of the minimum load of the thermal power unit under the DPRO state to ratio.

4. The power grid dispatching method taking into account the active feasible region of the coupled system of new energy and thermal power as claimed in claim 3 is characterized by: In S1, the output constraints of thermal power units are also met:

5. The power grid dispatching method taking into account the active feasible region of the coupling system of new energy and thermal power as claimed in claim 4, characterized in that: In S1, the general expression of the power constraint of thermal power units taking into account deep peak regulation is: Among them, U t represents the state of the unit at time t, U t =1 means the unit is in operation, U t =0 means the unit is in shutdown state.

6. The power grid dispatching method taking into account the active feasible region of the coupling system of new energy and thermal power as claimed in claim 5, characterized in that: In S1, if the thermal power unit parameters meet but ④ ⑤ Merge into:

7. The power grid dispatching method taking into account the active feasible region of the coupling system of new energy and thermal power as claimed in claim 6, characterized in that: In S3, the feasible domain of the active power of new energy at adjacent moments is: and in, is the maximum output power of the new energy in the coupling system at time t-1, is the maximum output power of the new energy in the coupling system at time t, P t r is the power generated by the new energy at the current moment, is the power generation of the new energy at time t-1.

8. The power grid dispatching method taking into account the active feasible region of the coupling system of new energy and thermal power as claimed in claim 7, characterized in that:

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