Water-light complementary load adjusting method for water-electricity and photovoltaic co-used electricity sending-out channel

Abstract

The invention discloses a water-light complementation load adjusting method for a water-power and photovoltaic co-used power delivery channel, and the method comprises the steps: S1, judging whether a current illumination condition supports photovoltaic power generation or not; S2, carrying out the load distribution according to a preset power generation mode of a conventional hydroelectric generating set; s3, calculating the residual capacity of the interconnecting transformer; s4, judging whether the residual capacity of the current interconnecting transformer is greater than the sum of the active power of the water-turbine generator set on the limited side or not; if yes, the step S5 is executed, and if not, the step S6 is executed; s5, the preset adjusting parameters and strategies are kept unchanged; s6, resetting the adjustable upper limit of the limited side unit; and S7, after the adjustable upper limit of the water turbine generator set on the limited side is modified, the active power which cannot be borne by the limited side is distributed to other water turbine sets on the unlimited side. By optimizing coordinated operation of hydroelectric power generation and photovoltaic power generation, complementation of the hydroelectric power generation and the photovoltaic power generation is achieved, and the stability and economic benefits of the whole system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of clean energy multi-energy complementarity, and in particular to a method for adjusting a water-photovoltaic complementary load in a hydropower and photovoltaic common electricity transmission channel. Background Art

[0002] In recent years, with the growing global demand for renewable energy, my country's power industry has also been actively promoting the development of new energy. In the past few years, a large number of new energy power stations have been built to transmit electricity with the help of the transmission lines of surrounding hydropower plants that have been put into operation. However, with the access of a large number of new energy plants, the operation mode and load characteristics of the power system have changed significantly. Especially for hydropower plants with shared transmission lines, the previous AGC (automatic generation control) regulation strategy was mainly designed for traditional hydropower generation. With the access of photovoltaic power stations, this has led to the following problems:

[0003] 1. Equipment overload: After photovoltaic power generation is connected, the load of some transmission lines and transformers increases significantly. The traditional AGC regulation strategy cannot effectively cope with it, resulting in the risk of equipment overload.

[0004] 2. Intensified system frequency fluctuations: The instability of photovoltaic power generation has intensified system frequency fluctuations. The existing AGC strategy has not been optimized for the characteristics of photovoltaic power generation, making it difficult to respond and adjust quickly, affecting the stability of the power grid.

[0005] 3. Load regulation lag: Under the combined effect of multiple power generation sources, the lag in regulation of the existing system leads to low efficiency in overall load distribution and cannot give full play to the advantages of photovoltaic power generation. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, the present invention proposes a water-photovoltaic complementary load adjustment method for a hydropower and photovoltaic shared electricity transmission channel, which can better manage the grid load, reduce the risk of power outages due to overload, and thus improve the reliability of the grid.

[0008] To achieve the above-mentioned purpose, the present invention provides, on one hand, a method for adjusting the water-photovoltaic complementary load of a hydropower and photovoltaic shared power transmission channel, comprising:

[0009] S1, first determine whether the current lighting conditions support photovoltaic power generation, if not, execute step S2; otherwise, execute step S3;

[0010] S2, load distribution according to the pre-set traditional hydropower unit power generation mode;

[0011] S3: If the conditions for photovoltaic power generation are met at this time, the output of the photovoltaic plant is guaranteed when the interconnection transformer power is not overloaded, and the remaining capacity of the interconnection transformer is calculated;

[0012] S4, determining whether the remaining capacity of the current interconnecting transformer is greater than the sum of the active powers of the hydro-generator sets on the restricted side; if so, executing step S5, otherwise executing step S6;

[0013] S5, maintaining the preset adjustment parameters and strategies unchanged;

[0014] S6, reset the adjustable upper limit of the units on the restricted side, and lower the adjustable upper limit of each unit on the restricted side;

[0015] S7, after the adjustable upper limit of the hydro-turbine generator set on the restricted side is modified, the active power that cannot be borne by the restricted side is distributed to the remaining hydro-turbine sets on the unrestricted side.

[0016] The water-photovoltaic complementary load adjustment method of the hydropower and photovoltaic common power transmission channel of the embodiment of the present invention may also have the following additional technical features:

[0017] In one embodiment of the present invention, the remaining capacity P of the linked transformer is assumed to be 联剩 , Rated capacity of the combined transformer S 联 , the combined reactive power Q 联 , the sum of active power of photovoltaic power plants P 光总 , the sum of active power of the transmission lines on the restricted side P 受限送出 ; The calculation of the remaining capacity of the interconnection transformer is:

[0018]

[0019] Then we have:

[0020]

[0021] In one embodiment of the present invention, the remaining capacity P of the linked transformer is assumed to be 联剩 , the sum of active power of the transmission lines on the restricted side P 受限水总 ; The determination of whether the remaining capacity of the current interconnection transformer is greater than the sum of the active powers of the hydro-generator sets on the restricted side:

[0022] P 联剩 >P 受限水总

[0023] Then we have:

[0024] P 联剩 >P 6G +P 7G .

[0025] In one embodiment of the present invention, the adjustable upper limit of each unit on the restricted side is proportionally distributed according to the rated capacity of each unit on the restricted side.

[0026] In one embodiment of the present invention,

[0027]

[0028] The water-photovoltaic complementary load adjustment method of the hydropower and photovoltaic shared power transmission channel of the embodiment of the present invention can better manage the grid load, reduce the risk of power outages caused by overload, and thus improve the reliability of the grid. Avoiding equipment overload can reduce the thermal and mechanical stress of the equipment, thereby reducing losses and extending the service life of the equipment. The AGC strategy optimized for photovoltaic power generation characteristics can quickly respond to frequency changes, reduce fluctuations, and improve the stability of the system frequency.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0031] Figure 1 It is a flow chart of a method for adjusting the water-photovoltaic complementary load of a hydropower and photovoltaic common power transmission channel according to an embodiment of the present invention;

[0032] Figure 2 This is a simplified wiring diagram of main equipment of a hydropower plant and a photovoltaic power plant that share a common power transmission channel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] The following describes a method for adjusting the water-photovoltaic complementary load of a hydropower and photovoltaic shared electricity transmission channel according to an embodiment of the present invention with reference to the accompanying drawings.

[0036] Figure 1 : is a flow chart of a method for adjusting the water-photovoltaic complementary load of a hydropower and photovoltaic shared power transmission channel according to an embodiment of the present invention. Figure 1 As shown, the method includes but is not limited to the following steps:

[0037] S1, first determine whether the current lighting conditions support photovoltaic power generation, if not, execute step S2; otherwise, execute step S3;

[0038] S2, load distribution according to the pre-set traditional hydropower unit power generation mode;

[0039] S3: If the conditions for photovoltaic power generation are met at this time, the output of the photovoltaic plant is guaranteed when the interconnection transformer power is not overloaded, and the remaining capacity of the interconnection transformer is calculated;

[0040] S4, determining whether the remaining capacity of the current interconnecting transformer is greater than the sum of the active powers of the hydro-generator sets on the restricted side; if so, executing step S5, otherwise executing step S6;

[0041] S5, maintaining the preset adjustment parameters and strategies unchanged;

[0042] S6, reset the adjustable upper limit of the units on the restricted side, and lower the adjustable upper limit of each unit on the restricted side;

[0043] S7, after the adjustable upper limit of the hydro-turbine generator set on the restricted side is modified, the active power that cannot be borne by the restricted side is distributed to the remaining hydro-turbine sets on the unrestricted side.

[0044] Figure 2 This is a schematic diagram of the main equipment wiring of the hydropower plant and photovoltaic power plant that share the power transmission channel of the present invention. Figure 2 In the example, hydroelectric generators (1G-7G in this example). Photovoltaic generators (8G-9G in this example). Busbars (500kV busbars, 35kV busbars, and 220kV busbars are drawn in this example). Transmission channels (Transmission channels 1-3 in this example). Interconnection transformers (500kV / 220kV / 35kV interconnection transformers in this example).

[0045] In order to present the problem more intuitively, the present invention can abstract one photovoltaic plant into one generator set. This example diagram is only drawn to more intuitively explain the strategy execution logic. The application scope of this strategy has nothing to do with the specific number of photovoltaic plants connected, the number of hydropower generator sets, the voltage level, and the number of transmission lines.

[0046] Specifically, the logic flow of the present invention is as follows: Figure 1 As shown:

[0047] Step 1: First determine whether the current lighting conditions support photovoltaic power generation. If not, proceed to step 2; otherwise, proceed to step 3. Since photovoltaic power generation has some particularities and has specific requirements for lighting conditions, and does not have power generation conditions at night, this time range can be specifically divided according to the local specific day and night change time.

[0048] Step 2: Since the conditions for photovoltaic power generation are not met at this time, the load can be distributed according to the previously set traditional hydropower unit power generation method.

[0049] Step 3: If the conditions for photovoltaic power generation are met at this time, the output of the photovoltaic plant should be guaranteed first when the power of the interconnection transformer is not overloaded. At this time, the remaining capacity of the interconnection transformer needs to be calculated. 联剩 , S of the rated capacity of the combined transformer 联 , the combined reactive power Q 联 , the sum of active power of photovoltaic power plants P 光总 , the sum of active power of the transmission lines on the restricted side P 受限送出 )

[0050]

[0051] by Figure 2 The example graph in is used for calculation, namely:

[0052]

[0053] Step 4: Determine whether the remaining capacity of the current interconnecting transformer is greater than the sum of the active powers of the hydro-generator sets on the restricted side.

[0054] (The remaining capacity of the joint transformer P 联剩 , the sum of active power of the transmission lines on the restricted side P 受限水总 )

[0055] P 联剩 >P 受限水总

[0056] by Figure 2 The example graph in is used for calculation, that is

[0057] P 联剩 >P 6G +P 7G

[0058] If the remaining capacity of the joint transformer is larger, go to step 5, otherwise go to step 6.

[0059] Step 5: At this time, the remaining capacity of the joint transformer is larger, so there is no need to adjust the originally set adjustment parameters and strategies.

[0060] Step 6: At this time, the sum of the active power of the turbine generator sets on the restricted side is greater. In order to ensure that the interconnecting transformer is not overloaded, it is necessary to reset the adjustable upper limit of the units on the restricted side and lower the adjustable upper limits of the units on the restricted side. Usually, the amplitude of the reduction is proportionally distributed according to the rated capacity of each unit on the restricted side.

[0061] by Figure 2 The example graph in is used for calculation, that is

[0062]

[0063] Step 7: After the adjustable upper limit of the turbine generator set on the restricted side is modified, the active power that the restricted side cannot bear will be distributed to the remaining turbine sets on the unrestricted side. Figure 2 In the example diagram, the active power that units 6 and 7 cannot bear will be allocated to units 1-5.

[0064] Furthermore, the present invention also follows the following regulation principles:

[0065] Principle 1: Give priority to photovoltaic power generation as much as possible. If the output of the photovoltaic power station increases and causes the interconnection transformer to be overloaded, the active power of the hydro-generator set on the restricted side should be reduced by the same amount to ensure the normal operation of the interconnection transformer;

[0066] Principle 2: The active power output of the hydropower plant remains unchanged. Due to the reduction in active power of the turbine generator set on the restricted side caused by Principle 1, in order to ensure that the active power output of the hydropower plant remains unchanged, the turbine set on the unrestricted side should bear the reduced active power output of the turbine set on the restricted side. Figure 2 For example, the active output of No. 6 and No. 7 hydro-turbine generator sets that is reduced due to the cooperation with the photovoltaic power station should be borne by units 1-5.

[0067] Principle 3: If the turbine unit on the unrestricted side has reached the upper limit of adjustable capacity, it will not participate in the regulation work related to Principle 2. The lost active output will be coordinated uniformly by the dispatching side.

[0068] Principle 4: Overload of transmission lines is not within the scope of this invention.

[0069] The water-photovoltaic complementary load adjustment method of the hydropower and photovoltaic shared power transmission channel of the embodiment of the present invention can better manage the load of the power grid, reduce the risk of power outages due to overload, and thus improve the reliability of the power grid. Avoiding equipment overload can reduce the thermal stress and mechanical stress of the equipment, thereby reducing losses and extending the service life of the equipment. The AGC strategy optimized for photovoltaic power generation characteristics can quickly respond to frequency changes, reduce fluctuations, and improve the stability of the system frequency. By improving the load regulation strategy, various power generation resources can be used more effectively, the overall energy utilization efficiency can be improved, and energy waste can be reduced. The optimized control strategy can better integrate renewable energy sources such as photovoltaics, and improve the adaptability and absorption capacity of the power grid to these intermittent energy sources.

[0070] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

Claims

1. A method for adjusting the water-photovoltaic complementary load of a hydropower and photovoltaic shared power transmission channel, characterized in that: include: S1, first determine whether the current lighting conditions support photovoltaic power generation, if not, execute step S2; otherwise, execute step S3; S2, load distribution according to the pre-set traditional hydropower unit power generation mode; S3: If the conditions for photovoltaic power generation are met at this time, the output of the photovoltaic plant is guaranteed when the interconnection transformer power is not overloaded, and the remaining capacity of the interconnection transformer is calculated; S4, determining whether the remaining capacity of the current interconnecting transformer is greater than the sum of the active powers of the hydro-generator sets on the restricted side; if so, executing step S5, otherwise executing step S6; S5, maintaining the preset adjustment parameters and strategies unchanged; S6, reset the adjustable upper limit of the units on the restricted side, and lower the adjustable upper limit of each unit on the restricted side; S7, after the adjustable upper limit of the hydro-turbine generator set on the restricted side is modified, the active power that cannot be borne by the restricted side is distributed to the remaining hydro-turbine sets on the unrestricted side.

2. The method according to claim 1, characterized in that The remaining capacity of the joint transformer P 联剩 , Rated capacity of the combined transformer S 联 , the combined reactive power Q 联 , the sum of active power of photovoltaic power plants P 光总 , the sum of active power of the transmission lines on the restricted side P 受限送出 ; The calculation of the remaining capacity of the interconnection transformer is: Then we have:

3. The method according to claim 2, characterized in that The remaining capacity of the joint transformer P 联剩 , the sum of active power of the transmission lines on the restricted side P 受限水总 ; The determination of whether the remaining capacity of the current interconnection transformer is greater than the sum of the active powers of the hydro-generator sets on the restricted side: P 联剩 >P 受限水总 Then we have: P 联剩 >P 6G +P 7G 。 4. The method according to claim 3, characterized in that The adjustable upper limit of each unit on the restricted side is proportionally distributed according to the rated capacity of each unit on the restricted side.

5. The method according to claim 4, characterized in that

Images