A power grid operation dispatching method considering the feasible region of coupled active power of multiple thermal power units

Abstract

The present invention relates to the technical field of electric power systems, and in particular to a method for dispatching power grid operation taking into account the active feasible domain of multiple thermal power units coupled, comprising: step 1, analyzing the active feasible domain of a single thermal power unit at adjacent moments in combination with the step-type climbing characteristics of the thermal power units; step 2, analyzing the main influencing factors of the active feasible domain of multiple thermal power units coupled at adjacent moments, and defining the basic operation rules of the active feasible domain at adjacent moments; step 3, analyzing the influence of the main influencing factors on the active feasible domain of multiple thermal power units coupled at adjacent moments, and deriving the active feasible domain of two thermal power units coupled at adjacent moments in combination with the basic operation rules. The method can reduce the difficulty of regulating the active power of the power grid system of the multi-thermal power unit coupling system, help solve the problem that the integrated dispatch of the whole network is difficult to handle a large number of generator sets, 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 operation dispatching method taking into account a feasible domain of coupled active power of multiple thermal power generating units. Background Art

[0002] When multiple thermal power units form an operating entity at the same grid connection point, these thermal power units can participate in grid dispatching and peak-shaving auxiliary services as a coupling system, thereby improving the overall control performance and economic benefits of the system.

[0003] At present, when the upper power grid of these multiple thermal power units coupling systems is operated and dispatched, each thermal power unit in the coupling system still sends its own active feasible domain to the upper power grid. The active feasible domain takes into account all the output conditions of each internal power source while depicting it, and includes all possibilities. The points within the active feasible domain can cooperate with the dispatch of the upper power grid. When the power grid system (i.e., the upper power grid) adjusts the active power, it uses the active feasible domain of each thermal power unit as the reference data for adjustment. However, this adjustment 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 thermal power unit, and then send the adjustment target to each thermal power unit separately. 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 (each 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 in a multi-thermal power unit coupling 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 operation dispatching method taking into account the active feasible domain of multiple thermal power unit coupling, which can reduce the difficulty of regulating the active power of the power grid system of the multiple thermal power unit coupling 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] A power grid operation dispatching method taking into account the active feasible region of multiple thermal power generation units coupling is used in a coupling system with multiple thermal power generation units, comprising the following steps:

[0010] Step 1: Analyze the feasible domain of active power of a single thermal power unit at adjacent moments in combination with the step-type ramp-up characteristics of the thermal power unit;

[0011] Step 2: Analyze the main influencing factors of the active power feasible domain at adjacent moments in the coupled scenario of multiple thermal power units, and define the basic calculation rules of the active power feasible domain at adjacent moments;

[0012] Step 3: Analyze the influence of the main influencing factors on the feasible domain of active power at adjacent moments in the multi-thermal power coupling scenario, and derive the feasible domain of active power at adjacent moments of the coupling of two thermal power units in combination with basic operation rules;

[0013] Step 4: Based on the analysis of the feasible domain of active power at adjacent moments of the coupling of two thermal power units, derive the general formula of the feasible domain of active power at adjacent moments of the coupling scenario of any number of thermal power units;

[0014] Step 5: According to the general formula of the active feasible domain at adjacent moments of the coupling scenario of any multiple thermal power units, combined with the number of thermal power units in the coupling system of each thermal power unit, the active feasible domain at adjacent moments of each thermal power unit coupling system is obtained and reported to the upper-level power grid, and the upper-level power grid performs operation scheduling of the power grid system with reference to the active feasible domain at adjacent moments of the coupling system of the thermal power units.

[0015] Preferably, in step 1, the active feasible region of the coupled system at adjacent moments is:

[0016]

[0017] 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 last moment, P min is the minimum active power allowed by the system, P max is the capacity of the system, Rn is the system ramp rate and system capacity P max , Δt is the scheduling time scale.

[0018] Preferably, in step 1, the feasible domain of active power of a single thermal power unit at adjacent moments is:

[0019]

[0020] in, For a single thermal power unit climbing up the slope, It is a downward climbing assembly of a single thermal power unit; and

[0021]

[0022]

[0023]

[0024] In the formula, 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.

[0025] Preferably, in step 2, the main influencing factors include the capacity combination, power and start and stop of the unit; the defined basic calculation rules of the active feasible domain at adjacent moments include:

[0026]

[0027]

[0028] in, is the symbol of the translation operation; Px is the translation power; The left shift operation is on the left side of the set. The left shift operation acts on the set Ω(P t-1 ,P t ,P max ) t Position; translation operator symbol The right side of the set is the right shift operation, which acts on the set Ω(P t-1 ,P t ,P max ) t-1 Location.

[0029] Preferably, step 3 comprises:

[0030] S3.1. Analyze the active power feasible domain of the two thermal power units without considering the start and stop of the thermal power units within the dispatch time scale Δt; obtain the active power feasible domain at adjacent moments without considering the start and stop of the units, and record it as the active basic feasible domain at adjacent moments Said The capacity of thermal power unit P1; is the capacity of motor group P2;

[0031] S3.2. Analyze the feasible region of starting P2 unit when only P1 unit is running The shutdown feasible region of P2 unit when both units are in operation Feasible region for starting P1 unit when only P2 unit is running And the feasible region of shutting down P1 unit when both units are running at the same time

[0032] S3.3, according to the analysis results of S.2, analyze and Calculation formula of

[0033] S3.4. Analyze the startup feasible region Ω of the coupled system on , halt feasible region Ω off and the basic feasible domain Then, the active feasible region Ω of the two thermal power units coupled is obtained. TH Calculation formula.

[0034] Preferably, in S3.1, the basic feasible domain of active power at adjacent moments is

[0035]

[0036] in, The capacity of thermal power unit P1; is the capacity of motor group P2.

[0037] Preferably, in S3.2, the feasible region for starting the P2 unit is only when the P1 unit is running.

[0038]

[0039] in:

[0040]

[0041] in, It is the ratio of the upper limit of the active power allowed to start the thermal power unit to the unit capacity; is the ratio of the lower limit of the active power allowed to start the thermal power unit to the unit capacity;

[0042] Will By swapping P1 and P2 in the expression, we can get the feasible region for starting P1 unit only when P2 unit is running.

[0043] The shutdown feasible region of P2 unit when both units are in operation

[0044]

[0045] in:

[0046]

[0047] In the formula, It is the ratio of the lower limit of active power that is allowed to be shut down for thermal power units to the unit capacity; is the ratio of the upper limit of active power allowed to be shut down for thermal power units to the unit capacity;

[0048] Will Swap P1 and P2 in the expression to obtain the shutdown feasible region of P1 unit when both units are running.

[0049] Preferably, in S3.3, and The calculation formula is

[0050]

[0051] in:

[0052]

[0053]

[0054] Will By swapping P1 and P2 in the calculation formula, we get Calculation formula of

[0055] Will By swapping P1 and P2 in the calculation formula, we get Calculation formula.

[0056] Preferably, in S3.4, the active feasible region of the coupling of the two thermal power generating units is calculated by the following calculation formula:

[0057] Ω TH =Ω TH '∪Ω on ∪Ω off ;

[0058]

[0059] Preferably, in step 4, the calculation formula for the active power feasible domain of any multiple thermal power units coupled scenario at adjacent moments is:

[0060] Ω TH =Ω TH '∪Ω on ∪Ω off ;

[0061] Among them, Ω TH The calculation formula of ' is:

[0062]

[0063]

[0064] Where n is the number of thermal power units in the system; P 1,max , P 2,max , P 3,max …P n,max are the capacities of n thermal power units respectively; i1, i2…i n are all positive integers not greater than n;

[0065] Ω on The calculation formula is:

[0066]

[0067]

[0068] Where n is the total number of units in the system; x is the number of units started in the system within the scheduling time scale Δt; y is the number of units already in operation in the system; x, y are positive integers and x+y≤n; It represents the total feasible region for starting x additional thermal power units when y thermal power units are already in operation; j1, j2, j3…jn are all positive integers not greater than n; The table shows the capacity of motor group jk;

[0069] Ω off The calculation formula is:

[0070] in,

[0071]

[0072] In the formula, x' is the number of units that have stopped in the system within the scheduling time scale Δt, y' is the number of units that are already in operation in the system, x' and y' are positive integers not greater than n and x' <y’; It represents the total feasible region of shutting down x' thermal power units when there are y' thermal power units in operation: is the capacity of motor group j1; is the capacity of motor group j2, For thermal power unit j y'-x' capacity.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] 1. This application utilizes the characteristics of the coupled system of thermal power units that are coupled and integrated into a unified operating entity through the same grid connection point, and packages the active feasible domains of multiple thermal power units in the same coupled system, characterizes them as a whole, and then reports them to the superior power grid. 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, but only needs to refer to the active feasible domain of each coupled 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.

[0075] 2. 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 the multi-power coupling system can achieve 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.

[0076] 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.

[0077] 3. This method is based on a single thermal power unit, and is analyzed and derived from two thermal power units and multiple thermal power units in turn. In the derivation process, the capacity of each thermal power unit is fully considered. Even if the capacities of multiple thermal power units are different, the dynamic characteristics of the system's active power can be accurately described.

[0078] 4. When constructing the feasible domain of active power at adjacent moments, this method fully considers the impact of unit capacity combination, power distribution, and unit start and stop on the feasible domain of active power at adjacent moments in the multi-thermal power coupling scenario, and can accurately characterize the overall active power regulation capability of the multi-thermal power coupling scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] In order to make the purpose, technical solution and advantages of the invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0080] Figure 1 It is an overall flow chart of the embodiment;

[0081] Figure 2 Schematic diagram of the feasible domain of active power at adjacent moments in step 1 of the embodiment;

[0082] Figure 3 Schematic diagram of the feasible domain of active power of a single thermal power unit at adjacent moments in step 1 of the embodiment;

[0083] Figure 4 This is a schematic diagram of the basic feasible region of active power at adjacent moments of the coupling of two 600MW thermal power units in step 3 of the embodiment;

[0084] Figure 5 This is a schematic diagram of the basic feasible region of active power at adjacent moments of the coupling of 200MW and 600MW thermal power units in step 3 of the embodiment;

[0085] Figure 6 This is a schematic diagram comparing the actual running data and the derived results in step 3. DETAILED DESCRIPTION

[0086] The following is a further detailed description through specific implementation methods:

[0087] Example:

[0088] like Figure 1 As shown, this embodiment discloses a power grid operation dispatching method taking into account the active feasible region of multiple thermal power generation units coupled, which is characterized in that it is used in a coupled system with multiple thermal power generation units, and includes the following steps:

[0089] Step 1: Combined with the step-by-step ramping characteristics of thermal power units, the feasible domain of active power of a single thermal power unit at adjacent moments is analyzed.

[0090] For ease of understanding, take a simple system as an example and assume that 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 Rn, and the scheduling time scale is Δt, then the power of the system satisfies the ramp rate constraint:

[0091] P t-1 -R n P max Δt≤P t ≤P t-1 +R n P max Δt (1)

[0092] The active output of the system at any time meets the system output constraints:

[0093] P min ≤P t ≤P max (2)

[0094] Then the feasible domain of the system's active power at adjacent moments is:

[0095]

[0096] The feasible domain of the system's active power at adjacent moments is as follows: Figure 2 shown.

[0097] The operating status of thermal power units can be divided into three types: basic peak regulation (RPR), deep peak regulation without oil injection (DPR) and deep peak regulation with oil injection (DPRO). Since the maximum ramp rate and spinning reserve that a thermal power unit can provide at different times are closely related to its current peak regulation status, when a thermal power unit performs deep peak regulation, as the unit load decreases, in order to ensure stable operation of the unit, the ramp rate will be lower than its ramp rate in the RPR state, and the lower the unit load, the lower the ramp rate. Existing literature calls this ramp characteristic of a thermal power unit the step-type ramp characteristic of a thermal power unit. By determining the parameters of the thermal power unit and the scheduling time scale, the adjacent active feasible domain of a single thermal power unit taking into account the step-type ramp characteristic of the thermal power unit can be obtained.

[0098] Among them, the corresponding climbing rate and unit capacity of the thermal power unit under the three states of RPR, DPR and DPRO are The ratios are R1, R2 and R3, P t TH and are the active power of the thermal power unit at the current moment and the previous moment respectively, a1, a2 and a3 are the minimum and maximum load values ​​of the thermal power unit under the RPR, DPR and DPRO states respectively. The ratio of the minimum output of the unit You can use a3 express.

[0099] Taking a thermal power unit in a local power grid as an example, the ramp rates of the unit in RPR, DPR and DPRO states 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, this patent selects a given scheduling period Δt=30min 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 a single thermal power unit at adjacent moments is:

[0100]

[0101] in,

[0102] The feasible domain of the active power of this single thermal power unit at adjacent times is as follows Figure 3 shown.

[0103] At the same time, the active power feasible domain of a single thermal power unit at adjacent moments is divided into an upward climbing set and a downward climbing set. The upward climbing set of a single thermal power unit is defined as:

[0104]

[0105] The downward climbing set of a single thermal power unit is:

[0106]

[0107] The intersection of the upward climbing set of a single thermal power unit and the downward climbing set of a single thermal power unit is the feasible domain of the active power of a single thermal power unit at adjacent times:

[0108]

[0109] Step 2: Analyze the main influencing factors of the active power feasible domain at adjacent moments in the coupled scenario of multiple thermal power units, and define the basic calculation rules of the active power feasible domain at adjacent moments.

[0110] In specific implementation, the main factors affecting the feasible domain of active power at adjacent moments in the coupled scenario of multiple thermal power units include:

[0111] 1) Capacity combination: In the scenario of multiple thermal power units coupled, each thermal power unit corresponds to a different feasible domain due to its different unit capacity configuration, and needs to be analyzed one by one and superimposed in order;

[0112] 2) Power distribution: In this scenario, not only are the capacity configurations of each thermal power unit different, but their load conditions are also different. Even if the total active power of the system is the same, there are many possibilities for the active output of each unit. At this time, it is necessary to consider the active power distribution between units. Only by determining the active power of each unit at the previous moment can the active power boundary of the coupled system at the current moment be determined.

[0113] 3) Unit start and stop: Under the premise of meeting the start and stop power constraints of thermal power units, as the load demand changes, the coupled system receives dispatch instructions from the upper-level power grid, and the thermal power units in the system may start or stop. The active feasible domain of the complete coupled system at adjacent moments must consider the start and stop of thermal power units.

[0114] In order to derive the feasible domain of active power at adjacent moments in the multi-thermal power coupling scenario, the operation rules of the feasible domain of active power at adjacent moments are defined as follows: The symbol of the translation operation is defined as The translation operation is divided into left shift and right shift operation. Let Px be the translation power and define the translation operation symbol. The left shift operation is on the left side of the set. The left shift operation acts on the set Ω(P t-1 ,P t ,P max ) t Position, the operation rules are:

[0115]

[0116] Define the translation operator symbol The right side of the set is the right shift operation, which acts on the set Ω(P t-1 ,P t ,P max ) t-1 Position, the operation rules are:

[0117]

[0118] The two translation operations are applicable to the active power feasible region, the upward climbing set and the downward climbing set of a single thermal power unit at adjacent moments.

[0119] The translation operation acts on the coordinate plane. The left shift operation is to move the original feasible domain area up by Px in the coordinate plane, and the right shift operation is to move the area to the right by Px in the coordinate plane.

[0120] Step 3: Analyze the influence of the main influencing factors on the feasible domain of active power at adjacent moments in the multi-thermal power coupling scenario, and derive the feasible domain of active power at adjacent moments of the coupling of two thermal power units in combination with basic operation rules.

[0121] In specific implementation, step 3 includes:

[0122] S3.1. Analyze the active power feasible domain of the two thermal power units without considering the start and stop of the thermal power units within the dispatch time scale Δt; obtain the active power feasible domain at adjacent moments without considering the start and stop of the units, and record it as the active basic feasible domain at adjacent moments Said The capacity of thermal power unit P1; is the capacity of motor group P2;

[0123] S3.2. Analyze the feasible region of starting P2 unit when only P1 unit is running The shutdown feasible region of P2 unit when both units are in operation Feasible region for starting P1 unit when only P2 unit is running And the feasible region of shutting down P1 unit when both units are running at the same time

[0124] S3.3, according to the analysis results of S.2, analyze and Calculation formula of

[0125] S3.4. Analyze the startup feasible region Ω of the coupled system on , halt feasible region Ω off and the basic feasible domain Then, the active feasible region Ω of the two thermal power units coupled is obtained. TH Calculation formula.

[0126] In order to accurately describe the active feasible domain of the adjacent moments in the multi-thermal power coupling scenario, this patent considers the impact of the capacity combination, power allocation and start-up and shutdown of each unit in the system on its active feasible domain. For the case of two thermal power units coupled, the active feasible domain of the two thermal power units coupled is first analyzed without considering the start-up and shutdown of the thermal power units within the scheduling time scale Δt: Assume that the capacities of the two thermal power units P1 and P2 are and The feasible region of active power at adjacent moments without considering the start and stop of the unit is called the basic feasible region of active power at adjacent moments, denoted as The basic feasible domain of active power at adjacent moments of the coupling scenario of two thermal power units can be expressed as the capacity is and The union of the three single thermal power units’ active feasible regions, namely:

[0127]

[0128] like Figure 4 As shown in , the basic feasible domain of active power at adjacent moments of the coupled scenario of two 600MW thermal power units can be equivalent to the union of the feasible domains of active power at adjacent moments of a single 600MW and a single 1200MW thermal power unit; Figure 5 As shown in the figure, after the two thermal power units with capacities of 200MW and 600MW are coupled, their basic feasible domain of active power at adjacent moments is equivalent to the union of the feasible domains of the single 200MW, 600MW and 800MW thermal power units at adjacent moments.

[0129] However, in actual operation, according to the dispatching instructions issued by the superior power grid, the thermal power units may start and stop within the dispatching time scale, and the active power of the system will fall outside the basic feasible domain. In order to obtain the active feasible domain at adjacent moments in the complete coupling scenario of two thermal power units, it is necessary to analyze the impact of the start and stop of the units on the active feasible domain. It should be noted that the coupling system is a unified operating entity, and the start and stop of each unit in the system is aimed at ensuring that the overall power of the system meets the regulation instructions. Usually, start and stop instructions are not issued to different units in the system at the same time. Therefore, the feasible domain constructed by this patent does not analyze such scenarios.

[0130] Analyze the start and stop of two thermal power units in the coupling scenario. Assume that the capacities of P1 and P2 thermal power units are and When only P1 unit is running, start P2 unit, there are:

[0131]

[0132] This situation corresponds to an additional startup feasible domain. The startup feasible domain of starting the P2 unit when only the P1 unit is running is recorded as By calculation, we can get:

[0133]

[0134] in:

[0135]

[0136] In the formula, It is the ratio of the upper limit of the active power allowed to start the thermal power unit to the unit capacity; is the ratio of the lower limit of the active power allowed to start the thermal power unit to the unit capacity;

[0137] The shutdown feasible region of shutting down unit P2 when both units are running is denoted as By calculation, we get:

[0138]

[0139] in:

[0140]

[0141] Will By swapping P1 and P2 in the expression (i.e., replacing P1 with P2 and P2 with P1), we can obtain the feasible domain for starting the P1 unit when only the P2 unit is running. Will By swapping P1 and P2 in the expression, we can obtain the feasible region for stopping P1 when both units are running.

[0142] Only For example, By swapping P1 and P2 in the expression, we can obtain the feasible region for stopping P1 when both units are running.

[0143]

[0144] From formula (13) and formula (15), we can see that: starting P2 feasible region The original single unit P1 can be moved upward by climbing up the slope Afterwards, the original single unit P1 climbs downward and moves upward together Then take the intersection to get; the feasible region of P2 is stopped The original single unit P1 can be moved upwards and assembled to the right Afterwards, the original single unit P1 moves rightward with the downward climbing group Then the intersection is obtained by taking the intersection, that is, the startup feasible region and the shutdown feasible region can be obtained by taking the intersection after the basic translation operation of the corresponding translation amount of the upward and downward climbing sets of a single thermal power unit:

[0145]

[0146]

[0147] This method is also applicable to the derivation of the feasible region for starting and stopping the P1 unit.

[0148] Will By swapping P1 and P2 in the calculation formula, we get Calculation formula of

[0149] Will By swapping P1 and P2 in the calculation formula, we get Calculation formula.

[0150] The feasible region of the coupling of two thermal power systems is denoted as Ω TH , the union of all feasible regions of the system is recorded as Ω on , the union of all halting feasible regions is denoted as Ω off , taking into account the feasible region of start and stop Ω on ,Ω off and the basic feasible domain Finally, the active feasible region of the two thermal power units coupled is obtained:

[0151]

[0152] The correctness of the derivation results is verified by the operating data of two 600MW thermal power units in a power plant that can perform deep peak regulation. The active power scatter plot of the two thermal power units at adjacent times throughout 2020 is compared with the active power feasible domain of the two 600MW thermal power units at adjacent times described in the patent. The results are as follows: Figure 6 As shown. Figure 6 It can be seen that the active power operating points of the two units at adjacent moments cover the four derived feasible regions, and the feasible region basically conforms to the actual operation of thermal power.

[0153] Step 4: Based on the analysis of the feasible domain of active power at adjacent moments of the coupling of two thermal power units, derive the general formula of the feasible domain of active power at adjacent moments of the coupling scenario of any number of thermal power units.

[0154] First, we start with the simplest case. The feasible domain of active power basic at adjacent moments of n thermal power units with the same capacity can be expressed as:

[0155]

[0156] When the unit capacities are different, assume that the capacities of n thermal power units are P 1,max , P 2,max , P 3,max …P n,max , variables i1, i2…i n are all positive integers not greater than n, The feasible domain expression of active power basis at adjacent moments of multiple thermal power units coupling can be obtained:

[0157]

[0158] Taking the union of the basic feasible domain of the multi-thermal power unit system and the system start-stop feasible domain, we can get the feasible domain of active power at adjacent moments of multi-thermal power coupling. It should be noted that in a system with multiple thermal power units, multiple units may start or shut down in one scheduling cycle.

[0159] Let x be the number of units started in the system within the scheduling time scale Δt, and y be the number of units already in operation in the system, then It represents the total feasible region for starting x more thermal power units when y thermal power units are already running.

[0160] x,y are positive integers and satisfy the organic group quantity constraint:

[0161] x+y≤n (22)

[0162] about The derivation is as follows:

[0163]

[0164] Among them, j1, j2, j3…jn are all positive integers not greater than n; The table shows the capacity of motor group jk.

[0165] The feasible region for starting multiple thermal power units is all The superposition of:

[0166]

[0167] The derivation of the shutdown feasible region is similar to that of the startup feasible region. x' is the number of units that are shut down within the scheduling time scale Δt, y' is the number of units that are already running in the system, x' and y' are positive integers not greater than n and x'<y'. It represents the total feasible region of shutting down x' thermal power units when there are y' thermal power units in operation:

[0168]

[0169]

[0170]

[0171] in, is the capacity of motor group j1; is the capacity of motor group j2, For thermal power unit j y'-x' capacity.

[0172] Finally, the feasible domain of active power at adjacent moments of n thermal power units coupling is obtained as follows:

[0173] Ω TH =Ω TH '∪Ω on ∪Ω off (28)

[0174] Step 5: According to the general formula of the active feasible domain at adjacent moments of the coupling scenario of any multiple thermal power units, combined with the number of thermal power units in the coupling system of each thermal power unit, the active feasible domain at adjacent moments of each thermal power unit coupling system is obtained and reported to the upper-level power grid, and the upper-level power grid performs operation scheduling of the power grid system with reference to the active feasible domain at adjacent moments of the coupling system of the thermal power units.

[0175] Compared with the prior art, this application utilizes the characteristics of the coupled system of thermal power units that are coupled and integrated into a unified operating entity through the same grid connection point, and packages the active feasible domains of multiple thermal power units in the same coupled system, characterizes them as a whole, and then reports them to the superior power grid. 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, but only needs to refer to the active feasible domain of each coupled system. Such a dispatching method can greatly reduce the number of dispatching objects of the superior power grid, and better play the supporting role of the coupling system to the superior power grid, thereby improving the dispatching efficiency of the active power of the power grid system and reducing the difficulty of regulation. It helps multiple power sources to participate in the auxiliary service market in the form of a coupled system, thereby helping to solve the problem that the integrated dispatching of the entire network is difficult to handle a large number of generators.

[0176] In addition, this method fully considers the temporal state dependency of the system's active power regulation capability. When constructing the active feasible domain, not only the correlation between the output power that the system can achieve 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. This method is based on a single thermal power unit, and is analyzed and derived from two thermal power units and multiple thermal power units in turn. In the derivation process, the capacity of each thermal power unit is fully considered. Even if the capacities of multiple thermal power units are different, the system's active power dynamic characteristics can be accurately described. When constructing the active feasible domain at adjacent moments, this method fully considers the impact of unit capacity combination, power distribution, and unit start and stop on the active feasible domain at adjacent moments in the multi-thermal power coupling scenario, which can accurately characterize the overall active regulation capability of the multi-thermal power coupling scenario and ensure the regulation accuracy during emergency dispatch.

[0177] When this 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 scheduling is performed with reference to these active feasible domains at adjacent moments, the scheduling targets are basically within the active feasible domain of adjacent moments. 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). Thereby greatly improving the controllability of the active power scheduling of the power grid system. By characterizing the active feasible domain of the coupled system at adjacent moments, it is beneficial to better play the supporting role of the coupled system to the upper-level power grid, which is of great significance for solving the problem that the integrated scheduling of the entire network is difficult to handle a large number of generators, and the overall participation of the coupled system in power grid scheduling and peak-shaving auxiliary services.

[0178] 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 operation dispatching method taking into account the feasible region of active power coupling of multiple thermal power units, characterized in that: It is used for a coupled system with multiple thermal power units, including the following steps: Step 1: Analyze the feasible domain of active power of a single thermal power unit at adjacent moments in combination with the step-type ramp-up characteristics of the thermal power unit; Step 2: Analyze the main influencing factors of the active power feasible domain at adjacent moments in the coupled scenario of multiple thermal power units, and define the basic calculation rules of the active power feasible domain at adjacent moments; the main influencing factors include the capacity combination, power and start and stop of the units; Step 3: Analyze the influence of the main influencing factors on the feasible domain of active power at adjacent moments in the multi-thermal power coupling scenario, and derive the feasible domain of active power at adjacent moments of the coupling of two thermal power units in combination with basic operation rules; Step 4: Based on the analysis of the feasible domain of active power at adjacent moments of the coupling of two thermal power units, derive the general formula of the feasible domain of active power at adjacent moments of the coupling scenario of any number of thermal power units; Step 5: According to the general formula of the active feasible domain at adjacent moments of the coupling scenario of any multiple thermal power units, combined with the number of thermal power units in the coupling system of each thermal power unit, the active feasible domain at adjacent moments of each thermal power unit coupling system is obtained and reported to the upper power grid, and the upper power grid performs operation scheduling of the power grid system with reference to the active feasible domain at adjacent moments of the coupling system of the thermal power units; Wherein, step 3 comprises: S3.

1. Analyze the active power feasible domain of the two thermal power units without considering the start and stop of the thermal power units within the dispatch time scale Δt; obtain the active power feasible domain at adjacent moments without considering the start and stop of the units, and record it as the active basic feasible domain at adjacent moments Said is the capacity of thermal power unit P1; is the capacity of thermal power unit P2; 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; The feasible domain of the active power basis at adjacent moments is: in, It is the feasible region of the active power of thermal power unit P1 at adjacent moments; It is the feasible region of the active power of thermal power unit P2 at adjacent moments; It is the feasible region of the active power of thermal power unit P1 and thermal power unit P2 at adjacent times; S3.

2. Analyze the feasible region of starting P2 unit when only P1 unit is running The shutdown feasible region of P2 unit when both units are in operation Feasible region for starting P1 unit when only P2 unit is running And the feasible region of shutting down P1 unit when both units are running at the same time S3.3, according to the analysis results of S.2, analyze and Calculation formula of S3.

4. Analyze the startup feasible region Ω of the coupled system on , halt feasible region Ω off and the basic feasible domain Then, the active feasible region Ω of the two thermal power units coupled is obtained. TH Calculation formula of In S3.4, the feasible region of active power of the two thermal power units is calculated by the following formula: Oh TH =Oh TH' ∪Ω on ∪Ω off ; 2. The power grid operation dispatching method taking into account the active feasible region of multiple thermal power generation units coupled as claimed in claim 1 is characterized by: In step 1, the feasible domain of active power of the coupled system at adjacent moments 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 last moment, P min is the minimum active power allowed by the system, P max is the capacity of the system, Rn is the system ramp rate and system capacity P max , Δt is the scheduling time scale.

3. The power grid operation dispatching method taking into account the active feasible region of multiple thermal power generating units coupled as claimed in claim 2 is characterized by: In step 1, the feasible domain of active power of a single thermal power unit at adjacent times is: in, For a single thermal power unit climbing upward, It is a downward climbing assembly of a single thermal power unit; and In the formula, 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 operation dispatching method taking into account the active feasible region of multiple thermal power generation units coupled as claimed in claim 3 is characterized by: In step 2, the basic operation rules of the active feasible domain at adjacent moments are defined as follows: in, is the symbol of the translation operation; Px is the translation power; The left shift operation is on the left side of the set. The left shift operation acts on the set Ω(P t-1, P t ,P max ) t Position; translation operator symbol The right side of the set is the right shift operation, which acts on the set Ω(P t-1 ,P t ,P max ) t-1 Location.

5. The power grid operation dispatching method taking into account the active feasible region of multiple thermal power generation units coupled as claimed in claim 4 is characterized by: In S3.2, the feasible region for starting P2 unit only when P1 unit is running in: in, It is the ratio of the upper limit of the active power allowed to start the thermal power unit to the unit capacity; is the ratio of the lower limit of the active power allowed to start the thermal power unit to the unit capacity; Will By swapping P1 and P2 in the expression, we can get the feasible region for starting P1 unit only when P2 unit is running. The shutdown feasible region of P2 unit when both units are in operation in: In the formula, It is the ratio of the lower limit of active power that is allowed to be shut down for thermal power units to the unit capacity; is the ratio of the upper limit of active power allowed to be shut down for thermal power units to the unit capacity; Will By swapping P1 and P2 in the expression, we can obtain the feasible region for stopping P1 when both units are running.

6. The power grid operation dispatching method taking into account the active feasible region of multiple thermal power generation units coupled as claimed in claim 5, characterized in that: In S3.3, and The calculation formula is in: Will By swapping P1 and P2 in the calculation formula, we get Calculation formula of Will By swapping P1 and P2 in the calculation formula, we get Calculation formula.

7. The power grid operation dispatching method taking into account the active feasible region of multiple thermal power generating units coupled as claimed in claim 6 is characterized by: In step 4, the calculation formula for the active power feasible domain of any multiple thermal power units coupled scenario at adjacent moments is: Oh TH =Oh TH' ∪Ω on ∪Ω off ; Among them, Ω TH The calculation formula of ' is: Where n is the number of thermal power units in the system; P 1,max , P 2,max , P 3,max …P n,max are the capacities of n thermal power units respectively; i1, i2…i n are all positive integers not greater than n; Ω on The calculation formula is: When x=n-1,y=1: Where n is the total number of units in the system; x is the number of units started in the system within the scheduling time scale Δt; y is the number of units already in operation in the system; x, y are positive integers and x+y≤n; It represents the total feasible region for starting x additional thermal power units when y thermal power units are already in operation; j1, j2, j3…jn are all positive integers not greater than n; The table shows the capacity of motor group jk; Ω off The calculation formula is: in, In the formula, x' is the number of units that have stopped in the system within the scheduling time scale Δt, y' is the number of units that are already in operation in the system, x' and y' are positive integers not greater than n and x' <y’; It represents the total feasible region of shutting down x' thermal power units when there are y' thermal power units in operation: is the capacity of motor group j1; is the capacity of motor group j2, For thermal power unit j y'-x' capacity.

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