CN112116161A - Distributed optimization planning method for rural transformer - Google Patents

Distributed optimization planning method for rural transformer Download PDF

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CN112116161A
CN112116161A CN202011024829.7A CN202011024829A CN112116161A CN 112116161 A CN112116161 A CN 112116161A CN 202011024829 A CN202011024829 A CN 202011024829A CN 112116161 A CN112116161 A CN 112116161A
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王占伟
陈海东
高晋
吴坚
李德民
李纪伟
谢岩
孙月亭
王昱衡
孙秋明
王雪峰
孙才华
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Jixi Power Supply Company State Grid Heilongjiang Electric Power Co ltd
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Abstract

The invention relates to a distributed optimization planning method for a rural transformer, which comprises the following steps: (1) establishing a load prediction model considering the novel load access to a power grid; (2) constructing a network planning model of the distributed distribution transformer by taking the minimum comprehensive cost as a target, and planning a power supply area of the distribution transformer; (3) and generating a low-voltage circuit layout scheme by adopting a minimum spanning tree theory of a graph theory in combination with the position of the distribution transformer and the power supply range thereof. The invention not only improves the reliability and economy of rural power grid power supply, but also has important significance for promoting novel rural development and future rural power grid transformation.

Description

Distributed optimization planning method for rural transformer
Technical Field
The invention relates to the technical field of transformer distributed optimization, in particular to a distributed optimization planning method for a rural transformer considering interconnection of a novel load and a low-voltage side.
Background
In recent years, the proportion of new loads represented by electric heating, namely electric energy replacing loads, is increasing day by day, and the development is rapid. The development of the novel load is not limited to cities, and the rural areas with wide land occupation in China also attract the addition of the novel load. However, unlike the urban power grid, the rural power grid is not favorable for improving the utilization rate of related equipment after grid-connected operation due to the seasonal characteristics of obvious loads such as farmland irrigation, electric heating and the like, so that the power supply economy is reduced therewith. Therefore, by utilizing the flexibility of power distribution operation, the novel load and the agricultural load are seasonally complemented, and the high-efficiency operation method of the distribution transformer is researched, so that the method provides guidance for the upgrading and transformation measures and development paths of the novel rural power grid in the future.
Load prediction is the basis of power grid planning, and the methods adopted at present are divided into regression analysis, a method elasticity coefficient method, a unit consumption method and the like. The rise of rural economy provides new requirements for planning and developing corresponding power distribution networks in rural areas, so that part of rural power networks cannot meet the requirements of novel towns in the aspects of power utilization quality, power supply reliability, equipment optimization and the like.
The prediction of the novel load and the traditional rural power grid load is the basis for power grid construction and reconstruction. On the basis, power supply reliability and economy need to be considered when power grid planning is carried out, wherein the planning of the distributed transformer mainly comprises two methods of optimizing distribution transformer configuration and adopting an on-load capacity-regulating distribution transformer. In the prior art, a self-adaptive load type distribution transformer realizes automatic switching of a rated capacity operation mode of the transformer according to an actual situation under the condition of not cutting off a load. Compared with a traditional planning method layout scheme adopted by a conventional distribution transformer, the distribution transformer network optimization planning method adaptive to seasonal loads is provided, a distribution transformer network double-layer planning model is constructed, feasibility is verified through examples, distribution transformer loss can be reduced, and reliability and economy of power supply are improved. However, the influence of novel loads and the like on rural loads is not considered in the prior art, and the load prediction result is different from the actual load prediction result.
Disclosure of Invention
The invention aims to solve the technical problem of providing a distributed optimization planning method for a rural transformer considering interconnection of a novel load and a low-voltage side.
The invention is realized by the following technical scheme:
a distributed optimization planning method for a rural transformer comprises the following steps:
(1) establishing a load prediction model considering the novel load access to a power grid;
(2) constructing a network planning model of the distributed distribution transformer by taking the minimum comprehensive cost as a target, and planning a power supply area of the distribution transformer;
(3) and generating a low-voltage circuit layout scheme by adopting a minimum spanning tree theory of a graph theory in combination with the position of the distribution transformer and the power supply range thereof.
Further, in the distributed optimization planning method for the rural transformer, in the step (1), the control strategy takes the minimum deviation value between the actual temperature and the set value as a target function, and the load prediction model is established as follows:
Figure BDA0002701849500000021
wherein: t istIs the actual value of the room temperature at the time period t; t issetIs a set value of room temperature; php,tIs the electrical power output of the heat pump for a period t; qhp,tIs the thermal power output of the heat pump for a period t; hload,tIs the t period heat load demand; php_rateIs the rated electrical power output of the heat pump.
Further, in the distributed optimization planning method for the rural transformer, in the step (1), the minimum cost of electric heating of the user is taken as a target, and a start-stop strategy model of the electric heating equipment is as follows:
Figure BDA0002701849500000031
wherein: pe,tThe electric power of the electric heating equipment at the moment t; c. CtThe electricity price is the electricity price at the moment t; pemax、PeminThe upper limit and the lower limit of the electric power of the device; he,tThe heat supply quantity of the electric heating equipment at the time t; hc,tThe heat supply amount of the heat storage device at the moment t; hload,tIs the t period heat load demand; stThe heat storage capacity of the heat storage device at the moment t; smaxIs the maximum heat storage amount of the heat storage device.
Further, in the distributed optimization planning method for the rural transformer, the comprehensive cost calculation formula in the step (2) is as follows:
minC＝αCIV+COPE
Figure BDA0002701849500000032
Figure BDA0002701849500000033
Figure BDA0002701849500000034
Figure BDA0002701849500000035
Figure BDA0002701849500000036
wherein: cIV＝CT+CCON+CLL
In the formula, CIVInitial investment cost for the system; cOPECost for system operation maintenance; n is a radical ofiDistributing the total number of load points for the ith distribution transformer; sHmi_dDistributing and changing capacity required by the d-th load point in a small load season; smiRated capacity of ith distribution transformer in light load season; sHXi_dDistributing and changing capacity required by the d-th load point in a heavy load season; sXiRated capacity of ith distribution transformer in heavy load season; smjRated capacity of the distribution transformer is operated in the j-th distribution transformer group in the medium and small load season; n is a radical ofjChanging the number of the jth distribution transformer group; sj_iRated capacity of ith distribution transformer of jth distribution transformer group; n is a radical ofnodeIs the total number of nodes;
Figure BDA0002701849500000041
the load value of the e-th node at the t moment; n is a radical ofTThe total number of the distribution transformers to be selected; n is a radical ofLLThe total number of the low-voltage lines; n is a radical ofCONThe total number of the connecting lines; pt LT_eThe active loss of the e-th transformer at the moment t; pt LL_eThe active loss of the e-th low-voltage line at the moment t; pt LCON_eThe active loss of the e-th connecting line at the moment t;
Figure BDA0002701849500000042
an active power value transmitted for a large power grid; u shapeeThe voltage value of the e node;
Figure BDA0002701849500000043
is the maximum value of the allowed voltage of the e-th node;
Figure BDA0002701849500000044
is the minimum value of the allowed voltage of the e-th node;
Figure BDA0002701849500000045
the maximum allowable power value of the c low-voltage line; pLL_cThe active power value of the c low-voltage line; pCON_aThe active power value of the a-th connecting line;
Figure BDA0002701849500000046
the maximum allowable power value of the a-th tie line; tau is the bank interest rate; t isPThe life cycle is full; alpha is the equipment equivalent annual coefficient; cTCost of construction for distribution transformers; cCONCosts are built for the interconnections between distribution transformers; cLLThe construction cost of the low-voltage line is reduced.
Further, in the distributed optimization planning method for the rural transformer, the construction cost formulas of the distribution transformer, the tie line and the low-voltage line are as follows:
Figure BDA0002701849500000047
wherein, CTCost of construction for distribution transformers; n is a radical ofTThe total number of the distribution transformers to be selected; cT_iInvestment cost is built for the ith distribution transformer; cCONCosts are built for the interconnections between distribution transformers; n is a radical ofCONThe total number of the connecting lines; cCON_aInvestment cost for the construction of the a-th connecting line; l isCON_aThe length of the a-th connecting line; pCON_aConstructing investment cost for the unit length of the a-th connecting line; cLLCost of low voltage line construction; n is a radical ofLLThe total number of the low-voltage lines; cLL_cInvestment cost for the construction of the c-th low-voltage line; lLL_cThe length of the ith low-voltage line; p is a radical ofLL_cAnd (5) investment cost is built for the unit length of the c low-voltage line.
Further, in the distributed optimization planning method for the rural transformer, the calculation formula of the operation and maintenance cost of the system is as follows:
COPE＝CM+CL
wherein, COPEIs the system operation and maintenance cost; cMIs the maintenance cost of the system; cLIs the operating loss cost of the system.
Further, in the distributed optimization planning method for the rural transformer, the calculation formula of the overhaul and maintenance cost and the operation loss cost of the system is as follows:
Figure BDA0002701849500000051
Figure BDA0002701849500000052
in the formula, NTThe total number of the distribution transformers to be selected; n is a radical ofLLThe total number of the low-voltage lines; n is a radical ofCONThe total number of the connecting lines; cMT_iThe maintenance cost for the ith distribution transformer; cMCON_aThe maintenance cost of the a-th connecting line; cMLL_cThe maintenance cost of the c-th low-voltage line; cLTLoss cost for distribution transformers; cLCONLoss cost for the tie line; cLLLLoss cost for low voltage lines; wLT_i、WLCON_a、WLLL_cRespectively representing the electric energy loss of the ith transformer, the a-th tie line and the c-th low-voltage line; p is a radical ofsRepresenting the system electricity price;
Figure BDA0002701849500000053
when each indicates tEtching active power loss of an ith transformer, an a th tie line and a c th low-voltage line; t isLT_i、TLCON_a、TLLL_cAre respectively indicated
Figure BDA0002701849500000054
Figure BDA0002701849500000061
The duration of (d); p0_iThe no-load comprehensive power loss of the ith distribution transformer; pK_iIntegrating power loss for the rated load of the ith distribution transformer; beta is the load factor of the distribution transformer; siApparent power output for the ith distribution transformer; sNiRated capacity for the ith distribution transformer;
Figure BDA0002701849500000062
respectively indicating the current of the a-th tie line and the c-th low-voltage line at the moment t; rLCON_a、RLLL_cThe resistances of the a-th tie line and the c-th low-voltage line are respectively indicated.
Further, in the distributed optimization planning method for the rural transformer, a capacity calculation formula of the distribution transformer is as follows:
SH＝RSPH
Figure BDA0002701849500000063
wherein S isHThe capacity required by the distribution transformer within a specified age; rSIs a capacity-to-load ratio; pHThe load is the current year; k1Is the load dispersion coefficient; k2An economic load factor for the distribution transformer; k3Is the power load development coefficient;
Figure BDA0002701849500000064
is the power factor; k1Is 1.1, K20.6 to 0.7, K31.3 to 1.5 of a surfactant,
Figure BDA0002701849500000065
is 0.8.
Further, in the method for distributed optimal planning of a rural transformer, the step of planning a distribution transformer in the step (2) is as follows:
step 1: generating each load block; generating load blocks according to the load prediction model result in the step (1), and numbering the central points of the load blocks as ql(l＝1，2，3……nl) The ratio of the load amount corresponding to each central point is alphal(l＝1，2，3……nl)；
Step 2: initializing a system; let alphaf1(f is 1, 2, 3, …, n) and primarily allocating a power supply area;
step 3: updating a system; obtaining the total load P of each distribution transformer from the nth divided power supply regioni(n) combined with distribution transformer capacity SiCalculating the load rate, and adjusting the coefficients of all the distribution transformers to subdivide power supply areas;
if the load factor is low, the power supply capability factor alpha of the corresponding distribution transformer needs to be reducediFor dividing more loads, the coefficient calculation mode of the (n + 1) th iteration is as follows:
Figure BDA0002701849500000071
step 4: judging; and repeating Step 3 until each distribution transformation load rate meets the requirement or the number of termination iterations is reached.
Further, in the distributed optimization planning method for the rural transformer, the low-voltage line layout scheme in the step (3) is as follows:
forming different net rack planning areas according to the power supply range of each distribution transformer, wherein distribution transformer and load points are equal to nodes in a minimum spanning tree; taking the position of each transformer as a root node, regarding the specifications of each line to be planned as consistent, enabling each edge to meet the equal requirements in the graph theory, and generating a minimum tree in each power supply area according to a graph theory program to form a target grid frame;
and reasonably modifying the target net rack according to the formed target net rack and by combining the actual load of each line.
The invention has the advantages and effects that:
the distributed optimization planning method for the rural transformer provides a new idea for the development of a rural power grid with high-proportion access of novel loads, is favorable for reducing the no-load loss of the distribution transformer, not only improves the reliability and the economical efficiency of power supply, but also has important significance for promoting the development of novel rural areas and the transformation of future rural power grids.
Drawings
Fig. 1 is a flowchart illustrating steps of a distributed optimization planning method for a rural transformer according to an embodiment of the present invention;
fig. 2 shows a schematic diagram of load block division in the distributed optimization planning method for the rural transformer according to an embodiment of the present invention.
Detailed Description
In order to make the implementation objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are only some, but not all embodiments of the invention. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Embodiments of the present invention are described in detail below with reference to the accompanying drawings:
under the background of countryside joy, the novel load technology represented by electric heating in the current market is developed greatly and is mature. According to the heat supply mode, the method is divided into a distributed mode and a centralized mode. The centralized electric heating has higher automation degree, safety and reliability, such as a heat accumulating type electric boiler, and meanwhile, the heat efficiency can reach 98 percent; the distributed electric heating system has the advantages of uniform heating, comfort, no dryness, excellent safety performance, strong controllability, realization of individual household time-sharing control and efficiency approaching 100 percent.
As shown in fig. 1, the distributed optimization planning method for the rural transformer includes the following steps:
(1) and establishing a load prediction model considering the novel load access to the power grid.
The load prediction of the equipment controlled by different strategies is carried out by the directly-heated equipment and the heat accumulating type equipment on the basis of the known heat load demand. The control strategy takes the minimum deviation value of the actual temperature and the set value as a target function, and the established load prediction model is as follows:
Figure BDA0002701849500000081
wherein: t istIs the actual value of the room temperature at the time period t; t issetIs a set value of room temperature; php,tIs the electrical power output of the heat pump for a period t; qhp,tIs the thermal power output of the heat pump for a period t; hload,tIs the t period heat load demand; php_rateIs the rated electrical power output of the heat pump.
The heat accumulating type electric heating is started in the load valley, and the electric energy is directly utilized to generate heat for heating; the system is stopped at the time of load peak, and the heat load demand is balanced by the aid of the heat storage device. The minimum cost of electric heating of a user is taken as a target, and the starting and stopping strategy model of the electric heating equipment is as follows:
Figure BDA0002701849500000082
wherein: pe,tThe electric power of the electric heating equipment at the moment t; c. CtThe electricity price is the electricity price at the moment t; pemax、PeminThe upper limit and the lower limit of the electric power of the device; he,tThe heat supply quantity of the electric heating equipment at the time t; hc,tThe heat supply amount of the heat storage device at the moment t; hload,tIs the t period heat load demand; stThe heat storage capacity of the heat storage device at the moment t; smaxIs the maximum heat storage amount of the heat storage device.
And solving the formulas (1) and (2) to obtain a user electric heating load characteristic curve.
(2) And constructing a network planning model of the distributed distribution transformer by taking the minimum comprehensive cost as a target, and planning a power supply area of the distribution transformer.
The distributed optimization planning method for the rural transformer performs optimization planning on the distribution transformer from the economic perspective, constructs a distribution transformer planning model with the minimum comprehensive cost as a target, and considers transformer capacity constraint, power balance constraint, node voltage constraint, censer flow constraint and the like under different operation modes. The comprehensive cost comprises initial investment cost and operation and maintenance cost, the time value of capital is considered, and the calculation formula of the comprehensive cost is as follows:
minC＝αCIV+COPE (3)
Figure BDA0002701849500000091
Figure BDA0002701849500000092
Figure BDA0002701849500000093
Figure BDA0002701849500000094
Figure BDA0002701849500000095
wherein: cIV＝CT+CCON+CLL
In the formula, CIVInitial investment cost for the system; cOPECost for system operation maintenance; n is a radical ofiDistributing the total number of load points for the ith distribution transformer; sHmi_dDistribution capacity required by the d-th load point in small load season；SmiRated capacity of ith distribution transformer in light load season; sHXi_dDistributing and changing capacity required by the d-th load point in a heavy load season; sXiRated capacity of ith distribution transformer in heavy load season; smjRated capacity of the distribution transformer is operated in the j-th distribution transformer group in the medium and small load season; n is a radical ofjChanging the number of the jth distribution transformer group; sj_iRated capacity of ith distribution transformer of jth distribution transformer group; n is a radical ofnodeIs the total number of nodes;
Figure BDA0002701849500000101
the load value of the e-th node at the t moment; n is a radical ofTThe total number of the distribution transformers to be selected; n is a radical ofLLThe total number of the low-voltage lines; n is a radical ofCONThe total number of the connecting lines; pt LT_eThe active loss of the e-th transformer at the moment t; pt LL_eThe active loss of the e-th low-voltage line at the moment t; pt LCON_eThe active loss of the e-th connecting line at the moment t;
Figure BDA0002701849500000102
an active power value transmitted for a large power grid; u shapeeThe voltage value of the e node;
Figure BDA0002701849500000103
is the maximum value of the allowed voltage of the e-th node;
Figure BDA0002701849500000104
is the minimum value of the allowed voltage of the e-th node;
Figure BDA0002701849500000105
the maximum allowable power value of the c low-voltage line; pLL_cThe active power value of the c low-voltage line; pCON_aThe active power value of the a-th connecting line;
Figure BDA0002701849500000106
the maximum allowable power value of the a-th tie line; tau is the bank interest rate; t isPThe life cycle is full; alpha is the equipment equivalentA year coefficient; cTCost of construction for distribution transformers; cCONCosts are built for the interconnections between distribution transformers; cLLThe construction cost of the low-voltage line is reduced.
The initial investment cost of the system comprises the purchase, construction and installation costs of a distribution transformer, a connecting line and a low-voltage line, and belongs to one-time investment. The cost formulas for the construction of the distribution transformer, the tie line and the low-voltage line are as follows:
Figure BDA0002701849500000107
wherein, CTCost of construction for distribution transformers; n is a radical ofTThe total number of the distribution transformers to be selected; cT_iInvestment cost is built for the ith distribution transformer; cCONCosts are built for the interconnections between distribution transformers; n is a radical ofCONThe total number of the connecting lines; cCON_aInvestment cost for the construction of the a-th connecting line; l isCON_aThe length of the a-th connecting line; pCON_aConstructing investment cost for the unit length of the a-th connecting line; cLLCost of low voltage line construction; n is a radical ofLLThe total number of the low-voltage lines; cLL_cInvestment cost for the construction of the c-th low-voltage line; lLL_cThe length of the ith low-voltage line; p is a radical ofLL_cAnd (5) investment cost is built for the unit length of the c low-voltage line.
The operation and maintenance cost of the system refers to all expenses spent in the operation process of the system, and mainly comprises operation loss cost and maintenance cost. The system operation and maintenance cost calculation formula is as follows:
COPE＝CM+CL (9)
wherein, COPEIs the system operation and maintenance cost; cMIs the maintenance cost of the system; cLIs the operating loss cost of the system.
The calculation formula of the overhaul and maintenance cost and the operation loss cost of the system is as follows:
Figure BDA0002701849500000111
Figure BDA0002701849500000112
in the formula, NTThe total number of the distribution transformers to be selected; n is a radical ofLLThe total number of the low-voltage lines; n is a radical ofCONThe total number of the connecting lines; cMT_iThe maintenance cost for the ith distribution transformer; cMCON_aThe maintenance cost of the a-th connecting line; cMLL_cThe maintenance cost of the c-th low-voltage line; cLTLoss cost for distribution transformers; cLCONLoss cost for the tie line; cLLLLoss cost for low voltage lines; wLT_i、WLCON_a、WLLL_cRespectively representing the electric energy loss of the ith transformer, the a-th tie line and the c-th low-voltage line; p is a radical ofsRepresenting the system electricity price;
Figure BDA0002701849500000113
respectively indicating the active power loss of the ith transformer, the a-th tie line and the c-th low-voltage line at the moment t; t isLT_i、TLCON_a、TLLL_cAre respectively indicated
Figure BDA0002701849500000114
Figure BDA0002701849500000115
The duration of (d); p0_iThe no-load comprehensive power loss of the ith distribution transformer; pK_iIntegrating power loss for the rated load of the ith distribution transformer; beta is the load factor of the distribution transformer; siApparent power output for the ith distribution transformer; sNiRated capacity for the ith distribution transformer;
Figure BDA0002701849500000116
respectively indicating the current of the a-th tie line and the c-th low-voltage line at the moment t; rLCON_a、RLLL_cThe resistances of the a-th tie line and the c-th low-voltage line are respectively indicated.
According to the regulation of 'rural power network planning and design guide' the capacity of the distribution transformer is selected according to a rural power development plan, and the capacity calculation formula of the distribution transformer is as follows:
SH＝RSPH (12)
Figure BDA0002701849500000121
wherein S isHThe capacity required by the distribution transformer within a specified age; rSIs a capacity-to-load ratio; pHThe load is the current year; according to the regulation of 'rural power network planning design guide rule', a rural low-voltage power network parameter K can be selected1Is the load dispersion coefficient; k2An economic load factor for the distribution transformer; k3Is the power load development coefficient;
Figure BDA0002701849500000122
is the power factor; k1Is 1.1, K20.6 to 0.7, K31.3 to 1.5 of a surfactant,
Figure BDA0002701849500000123
is 0.8.
Secondly, dividing the load points according to the load prediction result, forming different load blocks by considering geographic factors, and determining the central point q of each blocklPlus the load factor αlRepresenting the charge fraction of the load block. At the same time, the distribution transformer point qfAlso adding a power supply capability coefficient alphafRepresenting the power supply capability of the distribution transformer. The load block division is shown in fig. 2, where · is the center of each load patch.
The traditional Voronoi diagram method is improved, and the power supply capacity coefficient is continuously optimized through multiple iterations, so that the power supply range of each distribution transformer is reasonably divided. The power supply range is represented by the center point of each load block.
The specific steps for planning the distribution transformer are as follows:
step 1: generating each load block; generating load blocks according to the load prediction model result in the step (1), and numbering the central points of the load blocks as ql(l＝1，2，3……nl) The ratio of the load amount corresponding to each central point is alphal(l＝1，2，3……nl)；
Step 2: initializing a system; let alphaf1(f is 1, 2, 3, …, n) and primarily allocating a power supply area;
step 3: updating a system; obtaining the total load P of each distribution transformer from the nth divided power supply regioni(n) combined with distribution transformer capacity SiCalculating the load rate, and adjusting the coefficients of all the distribution transformers to subdivide power supply areas;
if the load factor is low, the power supply capability factor alpha of the corresponding distribution transformer needs to be reducediFor dividing more loads, the coefficient calculation mode of the (n + 1) th iteration is as follows:
Figure BDA0002701849500000131
step 4: judging; and repeating Step 3 until each distribution transformation load rate meets the requirement or the number of termination iterations is reached.
(3) And generating a low-voltage circuit layout scheme by adopting a minimum spanning tree theory of a graph theory in combination with the position of the distribution transformer and the power supply range thereof.
The rural low-voltage power grid is simple in structure and generally mainly adopts a radiation power supply mode. And generating a low-voltage circuit layout scheme by adopting a minimum spanning tree theory of a graph theory according to the characteristics of the low-voltage distribution network and combining the position of the distribution transformer and the power supply range of the distribution transformer. Firstly, all lines are considered to be equal, and then reasonable selection is carried out according to line loads by combining with practical situations. Specifically, the low-voltage circuit layout scheme is as follows:
forming different net rack planning areas according to the power supply range of each distribution transformer, wherein distribution transformer and load points are equal to nodes in a minimum spanning tree; taking the position of each transformer as a root node, regarding the specifications of each line to be planned as consistent, enabling each edge to meet the equal requirements in the graph theory, and generating a minimum tree in each power supply area according to a graph theory program to form a target grid frame;
and reasonably modifying the target net rack according to the formed target net rack and by combining the actual load of each line.
The above examples are only for illustrating the technical solutions of the present invention, and are not intended to limit the scope of the present invention. But all equivalent changes and modifications within the scope of the present invention should be considered as falling within the scope of the present invention.

Claims (10)

1. A distributed optimization planning method for a rural transformer is characterized by comprising the following steps:
(1) establishing a load prediction model considering the novel load access to a power grid;
(2) constructing a network planning model of the distributed distribution transformer by taking the minimum comprehensive cost as a target, and planning a power supply area of the distribution transformer;
(3) and generating a low-voltage circuit layout scheme by adopting a minimum spanning tree theory of a graph theory in combination with the position of the distribution transformer and the power supply range thereof.
2. The distributed optimized planning method for rural transformer according to claim 1, wherein in the step (1), the control strategy takes the minimum deviation value between the actual temperature and the set value as an objective function, and the load prediction model is established as follows:
Figure FDA0002701849490000011
wherein: t istIs the actual value of the room temperature at the time period t; t issetIs a set value of room temperature; php,tIs the electrical power output of the heat pump for a period t; qhp,tIs the thermal power output of the heat pump for a period t; hload,tIs the t period heat load demand; php_rateIs rated electricity of heat pumpAnd (4) power output.
3. The distributed optimization planning method for rural transformers according to claim 1 or 2, wherein in the step (1), the minimum cost of electric heating of the users is taken as a target, and the strategy model of starting and stopping the electric heating equipment is as follows:
Figure FDA0002701849490000012
wherein: pe,tThe electric power of the electric heating equipment at the moment t; c. CtThe electricity price is the electricity price at the moment t; pemax、PeminThe upper limit and the lower limit of the electric power of the device; he,tThe heat supply quantity of the electric heating equipment at the time t; hc,tThe heat supply amount of the heat storage device at the moment t; hload,tIs the t period heat load demand; stThe heat storage capacity of the heat storage device at the moment t; smaxIs the maximum heat storage amount of the heat storage device.
4. The distributed optimized planning method for rural transformer according to claim 1, wherein the calculation formula of the combined cost in step (2) is:
minC＝αCIV+COPE
Figure FDA0002701849490000021
Figure FDA0002701849490000022
Figure FDA0002701849490000023
Figure FDA0002701849490000024
Figure FDA0002701849490000025
wherein: cIV＝CT+CCON+CLL
In the formula, CIVInitial investment cost for the system; cOPECost for system operation maintenance; n is a radical ofiDistributing the total number of load points for the ith distribution transformer; sHmi_dDistributing and changing capacity required by the d-th load point in a small load season; smiRated capacity of ith distribution transformer in light load season; sHXi_dDistributing and changing capacity required by the d-th load point in a heavy load season; sXiRated capacity of ith distribution transformer in heavy load season; smjRated capacity of the distribution transformer is operated in the j-th distribution transformer group in the medium and small load season; n is a radical ofjChanging the number of the jth distribution transformer group; sj_iRated capacity of ith distribution transformer of jth distribution transformer group; n is a radical ofnodeIs the total number of nodes;
Figure FDA0002701849490000026
the load value of the e-th node at the t moment; n is a radical ofTThe total number of the distribution transformers to be selected; n is a radical ofLLThe total number of the low-voltage lines; n is a radical ofCONThe total number of the connecting lines; pt LT_eThe active loss of the e-th transformer at the moment t; pt LL_eThe active loss of the e-th low-voltage line at the moment t; pt LCON_eThe active loss of the e-th connecting line at the moment t;
Figure FDA0002701849490000031
an active power value transmitted for a large power grid; u shapeeThe voltage value of the e node;
Figure FDA0002701849490000032
is the maximum value of the allowed voltage of the e-th node;
Figure FDA0002701849490000033
is the minimum value of the allowed voltage of the e-th node;
Figure FDA0002701849490000034
the maximum allowable power value of the c low-voltage line; pLL_cThe active power value of the c low-voltage line; pCON_aThe active power value of the a-th connecting line;
Figure FDA0002701849490000035
the maximum allowable power value of the a-th tie line; tau is the bank interest rate; t isPThe life cycle is full; alpha is the equipment equivalent annual coefficient; cTCost of construction for distribution transformers; cCONCosts are built for the interconnections between distribution transformers; cLLThe construction cost of the low-voltage line is reduced.
5. The distributed optimization planning method for the rural transformer according to claim 4, wherein the construction cost formulas of the distribution transformer, the tie line and the low-voltage line are as follows:
Figure FDA0002701849490000036
wherein, CTCost of construction for distribution transformers; n is a radical ofTThe total number of the distribution transformers to be selected; cT_iInvestment cost is built for the ith distribution transformer; cCONCosts are built for the interconnections between distribution transformers; n is a radical ofCONThe total number of the connecting lines; cCON_aInvestment cost for the construction of the a-th connecting line; l isCON_aThe length of the a-th connecting line; pCON_aConstructing investment cost for the unit length of the a-th connecting line; cLLCost of low voltage line construction; n is a radical ofLLThe total number of the low-voltage lines; cLL_cInvestment cost for the construction of the c-th low-voltage line; lLL_cThe length of the ith low-voltage line; p is a radical ofLL_cFor the c-th low-voltage lineAnd investment cost for construction of unit length.
6. The distributed optimization planning method for the rural transformer according to claim 4, wherein the calculation formula of the operation and maintenance cost of the system is as follows:
COPE＝CM+CL
wherein, COPEIs the system operation and maintenance cost; cMIs the maintenance cost of the system; cLIs the operating loss cost of the system.
7. The distributed optimization planning method for the rural transformer according to claim 6, wherein the calculation formula of the overhaul maintenance cost and the operation loss cost of the system is as follows:
Figure FDA0002701849490000041
Figure FDA0002701849490000042
in the formula, NTThe total number of the distribution transformers to be selected; n is a radical ofLLThe total number of the low-voltage lines; n is a radical ofCONThe total number of the connecting lines; cMT_iThe maintenance cost for the ith distribution transformer; cMCON_aThe maintenance cost of the a-th connecting line; cMLL_cThe maintenance cost of the c-th low-voltage line; cLTLoss cost for distribution transformers; cLCONLoss cost for the tie line; cLLLLoss cost for low voltage lines; wLT_i、WLCON_a、WLLL_cRespectively representing the electric energy loss of the ith transformer, the a-th tie line and the c-th low-voltage line; p is a radical ofsRepresenting the system electricity price;
Figure FDA0002701849490000043
respectively refer to the ith transformer and the a-th tie line at the moment of tActive power loss of the c-th low-voltage line; t isLT_i、TLCON_a、TLLL_cAre respectively indicated
Figure FDA0002701849490000044
Figure FDA0002701849490000045
The duration of (d); p0_iThe no-load comprehensive power loss of the ith distribution transformer; pK_iIntegrating power loss for the rated load of the ith distribution transformer; beta is the load factor of the distribution transformer; siApparent power output for the ith distribution transformer; sNiRated capacity for the ith distribution transformer;
Figure FDA0002701849490000046
respectively indicating the current of the a-th tie line and the c-th low-voltage line at the moment t; rLCON_a、RLLL_cThe resistances of the a-th tie line and the c-th low-voltage line are respectively indicated.
8. The distributed optimization planning method for rural transformer according to claim 1, wherein the capacity of the distribution transformer is calculated by the following formula:
SH＝RSPH
Figure FDA0002701849490000051
wherein S isHThe capacity required by the distribution transformer within a specified age; rSIs a capacity-to-load ratio; pHThe load is the current year; k1Is the load dispersion coefficient; k2An economic load factor for the distribution transformer; k3Is the power load development coefficient;
Figure FDA0002701849490000052
is the power factor; k1Is 1.1, K2Is 0.6～0.7，K31.3 to 1.5 of a surfactant,
Figure FDA0002701849490000053
is 0.8.
9. The distributed optimization planning method for rural transformer according to claim 1, wherein the step of planning distribution transformer in step (2) is:
step 1: generating each load block; generating load blocks according to the load prediction model result in the step (1), and numbering the central points of the load blocks as ql(l＝1，2，3……nl) The ratio of the load amount corresponding to each central point is alphal(l＝1，2，3……nl)；
Step 2: initializing a system; let alphaf1(f is 1, 2, 3, …, n) and primarily allocating a power supply area;
step 3: updating a system; obtaining the total load P of each distribution transformer from the nth divided power supply regioni(n) combined with distribution transformer capacity SiCalculating the load rate, and adjusting the coefficients of all the distribution transformers to subdivide power supply areas;
if the load factor is low, the power supply capability factor alpha of the corresponding distribution transformer needs to be reducediFor dividing more loads, the coefficient calculation mode of the (n + 1) th iteration is as follows:
Figure FDA0002701849490000054
step 4: judging; and repeating Step 3 until each distribution transformation load rate meets the requirement or the number of termination iterations is reached.
10. The distributed optimized planning method for rural transformer according to claim 1, wherein the low-voltage line layout scheme in step (3) is:
forming different net rack planning areas according to the power supply range of each distribution transformer, wherein distribution transformer and load points are equal to nodes in a minimum spanning tree; taking the position of each transformer as a root node, regarding the specifications of each line to be planned as consistent, enabling each edge to meet the equal requirements in the graph theory, and generating a minimum tree in each power supply area according to a graph theory program to form a target grid frame;
and reasonably modifying the target net rack according to the formed target net rack and by combining the actual load of each line.
CN202011024829.7A 2020-09-25 2020-09-25 Distributed optimization planning method for rural transformer Pending CN112116161A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115378042A (en) * 2022-10-25 2022-11-22 国网江西省电力有限公司电力科学研究院 Distributed flexible resource coordination control method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115378042A (en) * 2022-10-25 2022-11-22 国网江西省电力有限公司电力科学研究院 Distributed flexible resource coordination control method
CN115378042B (en) * 2022-10-25 2023-02-17 国网江西省电力有限公司电力科学研究院 Distributed flexible resource coordination control method

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