CN115796611A

CN115796611A - Building power distribution system energy efficiency assessment and promotion method, system and storage medium

Info

Publication number: CN115796611A
Application number: CN202211353853.4A
Authority: CN
Inventors: 金强; 冯明灿; 丁羽頔; 郑宇光; 李敬如; 李红军; 阮文骏; 李瑶虹; 杨露露; 崔凯
Original assignee: State Grid Economic And Technological Research Institute Co LtdB412 State Grid Office; State Grid Corp of China SGCC; State Grid Jiangsu Electric Power Co Ltd
Current assignee: State Grid Economic And Technological Research Institute Co LtdB412 State Grid Office; State Grid Corp of China SGCC; State Grid Jiangsu Electric Power Co Ltd
Priority date: 2022-11-01
Filing date: 2022-11-01
Publication date: 2023-03-14

Abstract

The invention relates to a method, a system and a storage medium for evaluating and improving the energy efficiency of a building power distribution system, wherein the method comprises the following steps: normalizing indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system, and inputting a pre-established building power distribution network comprehensive evaluation model; obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index; combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result; and according to the evaluation result, the implementation energy efficiency of the power distribution network is improved, and the utilization efficiency of the no-load line is improved. The invention can realize the application of comprehensive energy of buildings and improve the utilization efficiency of no-load lines. The invention can be applied to the field of power distribution network construction and operation.

Description

Building power distribution system energy efficiency evaluation and improvement method, system and storage medium

Technical Field

The invention relates to the field of power distribution network construction and operation, in particular to a method and a system for evaluating and improving energy efficiency of a building power distribution system and a storage medium.

Background

The building is the most important object-oriented of the comprehensive energy service, and the building-oriented development of the comprehensive energy efficiency service, the multi-energy supply service and the distributed clean energy service is the direction of the key layout of the comprehensive energy service. The integrated energy service is object oriented and includes buildings, industries and parks. The building type customers, especially the public building type customers, have the advantages of large energy consumption and electricity consumption, stable load, good credit, strong payment capability and the like, and are the current key objects of concern. With the acceleration of the urbanization process of China, the building energy market is wide, more than 60% of the building energy is electric energy, and the building-oriented comprehensive energy service, the electric energy-based cold and heat supply service and the distributed clean energy service are developed and have strong advantages.

The comprehensive energy planning technology of the building with near-zero energy consumption and electricity as the center needs to be researched, the research on the layout and control strategy of the building direct-current power distribution system is developed, and technical conditions are provided for realizing the application of the comprehensive energy of the building and reducing the energy consumption.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a method, a system, and a storage medium for evaluating and improving energy efficiency of a building power distribution system, which can implement building comprehensive energy application and improve utilization efficiency of an unloaded line.

In order to realize the purpose, the invention adopts the following technical scheme: a building power distribution system energy efficiency assessment and promotion method comprises the following steps: after indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system are normalized, inputting a pre-established building power distribution network comprehensive evaluation model; obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index; combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result; according to the evaluation result, the implementation energy efficiency of the power distribution network is improved, so that the comprehensive energy application of the building can be realized, and the utilization efficiency of the no-load line can be improved.

Further, the comprehensive evaluation model of the building power distribution network is established by adopting a method of combining an analytic hierarchy process and a data enveloping method.

Further, the calculation of the final weight of the index comprises:

the method comprises the following steps of (1) solving the contribution degree of a single evaluation index to the energy efficiency of the whole power distribution system in a certain fixed state by utilizing energy transmission path analysis and a multi-dimensional function partial differential method;

and according to the obtained index contribution degree, giving final weight to the index by using an analytic hierarchy process.

Further, the obtaining of the evaluation result includes:

setting an input index vector, a corresponding input index weight vector, an output vector index and a corresponding output index weight vector of a certain DMU, and calculating to obtain the energy efficiency evaluation index number of the DMU; wherein, DMU is decision unit;

and obtaining the relative energy efficiency value sequencing of all DMUs according to the energy efficiency evaluation index number of the DMU, and determining the energy efficiency level according to the sequencing.

Further, the determining the energy efficiency level according to the ranking includes: the more the ranking is, the larger the relative energy efficiency value is.

Further, the efficiency is implemented to the distribution network and is promoted, include:

aiming at the weak energy efficiency link, a power distribution network equipment submerging high-efficiency system and a two-stage management mode for power distribution network voltage reactive power control are established;

the current limit is dynamically adjusted, the power distribution capacity is dynamically increased and the power supply potential is released through the calculation of the line current-carrying capacity based on meteorological factors;

and establishing a transformation economy evaluation system based on matching of line parameters, operation life, pre-access load characteristics and series compensation cost, and realizing the differential application of the no-load lines of the long-distance distribution network.

Further, the two-stage management mode of the voltage reactive power control of the power distribution network is as follows:

when the voltage of a station end or a platform area exceeds the limit and reactive power is reversely transmitted, an early warning is sent out, a power supply service command system is used for sending a capacitor switching short message, and the field reactive power compensation equipment management is implemented according to a switching instruction;

in the period of the overhaul load transfer of the transformer substation, the daily monitoring and analysis of the main transformer side and the line power factor are carried out: strengthening real-time monitoring of the voltage of the upper bus line; and adjusting an AVC reactive voltage control strategy, improving the reactive voltage control effect in an abnormal operation mode, and controlling the bus voltage and the power factor in an optimal interval.

A building power distribution system energy efficiency assessment and improvement system, comprising: the first processing module is used for normalizing indexes in an energy efficiency index system of the alternating current power distribution system and an energy efficiency index system of the direct current power distribution system and inputting a pre-established building power distribution network comprehensive evaluation model; the second processing module is used for obtaining the maximum or optimal contribution degree of the single index to the preset total target so as to determine the contribution degrees of different index quantities and further obtain the final weight of the index; the evaluation module is used for combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result; and the lifting module is used for lifting the power distribution network implementation energy efficiency according to the evaluation result and improving the utilization efficiency of the no-load line.

A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform any of the above methods.

A computing device, comprising: one or more processors, memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the above-described methods.

Drawings

Fig. 1 is a schematic flow chart of a method for evaluating and improving energy efficiency of a building power distribution system according to an embodiment of the invention;

fig. 2 is a detailed configuration diagram of an ac distribution network according to an embodiment of the present invention;

FIG. 3 is an energy efficiency level index system diagram for a DC building power distribution system in accordance with an embodiment of the present invention;

FIG. 4 is a simplified building DC power distribution system configuration in accordance with an embodiment of the present invention;

FIG. 5 is a schematic diagram of a structure in which an energy storage unit is connected to a DC bus side in parallel according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an embodiment of the invention in which an energy storage unit is connected in parallel to an outgoing line side of a distributed power supply;

FIG. 7 is a schematic diagram of a distributed power access unit building load side architecture in accordance with an embodiment of the present invention;

fig. 8 is a schematic structural diagram of an output side of a distributed power supply access grid-connected unit according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a system structure in which the feed lines are equivalent to resistors according to an embodiment of the present invention;

fig. 10 is a simplified diagram of a distributed power access scenario in accordance with an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the description of the embodiments of the invention given above, are within the scope of protection of the invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The invention provides a building power distribution system energy efficiency evaluation method, which comprises an alternating current power distribution system index system; a direct current distribution system index system; specification and analysis of the index quantity; and (5) building a comprehensive evaluation model.

From the practical perspective of engineering, aiming at the self-framework of the direct-current building power distribution system, the energy efficiency of the direct-current building power distribution system is related to other factors, such as the bus voltage qualified rate, the alternating-current side power factor and the like, and the actual condition of the system operation is difficult to reflect only through the converter efficiency and the line parameters.

The method aims at the problems that the research of near-zero energy consumption building comprehensive energy planning technology with electricity as the center is urgently needed, the research of the layout and control strategy of a building direct current power distribution system is developed, and technical conditions are provided for realizing building comprehensive energy application and reducing energy consumption. The invention provides a method, a system and a storage medium for evaluating and improving the energy efficiency of a building power distribution system, wherein the method comprises the following steps: normalizing indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system, and inputting a pre-established building power distribution network comprehensive evaluation model; obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index; combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result; and according to the evaluation result, the implementation energy efficiency of the power distribution network is improved, and the utilization efficiency of the no-load line is improved. The invention can realize the application of building comprehensive energy and improve the utilization efficiency of no-load lines.

In one embodiment of the invention, a building power distribution system energy efficiency assessment and promotion method is provided. In this embodiment, as shown in fig. 1, the method includes the following steps:

1) Normalizing indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system, and inputting a pre-established building power distribution network comprehensive evaluation model;

2) Obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index;

3) Combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result;

4) And according to the evaluation result, the implementation energy efficiency of the power distribution network is improved, and the utilization efficiency of the no-load line is improved.

In the step 1), the comprehensive evaluation model of the building power distribution network is established by adopting a method of combining an Analytic Hierarchy Process (AHP) and a data envelope process (DEA). And (3) carrying out normalization on indexes of each decision unit (design scheme) by utilizing grey system correlation degree analysis, converting different index parameters into comparable values with relative size relation, and taking the comparable values as input of a system energy efficiency level model.

In this embodiment, the suggestion of the energy efficiency index system of the ac power distribution system specifically includes:

in a traditional alternating-current power distribution network, on one hand, electric energy loss mainly comes from loss of a transformer and a line, and on the other hand, electric energy quality disturbance also has a remarkable influence on energy efficiency of a power grid. After the alternating-current power distribution network is connected to the direct-current power distribution network, new influences are generated on energy efficiency due to introduction of new devices such as a distributed power supply and an energy storage device. When the index system is constructed, the factors in the system are grouped according to whether the factors have commonality with each other, and the groups can be regarded as the factors in a new layer, so that the structure of the highest layer, the reference layer and the lowest layer is formed. In the embodiment, a power distribution network frame energy efficiency index system is established by analyzing and researching the network frame energy efficiency index and referring to the relevant standard specification.

The alternating current distribution network index system is divided into a static index and a dynamic index, wherein the static index is mainly a series of indexes related to equipment level, and the indexes comprise average power supply radius, average line cross section and energy-saving lead ratio. The dynamic indexes are indexes related to the operation of the distribution network, and comprise a three-phase compensation balance degree, a current harmonic distortion rate, a line load rate and a power factor qualification rate. The specific configuration is shown in fig. 2.

In this embodiment, the establishment of the direct current distribution system index system specifically includes:

aiming at the characteristics of the direct-current building power distribution system, the selection of the energy efficiency level evaluation index follows the following criteria. First, the evaluation index should reflect the actual condition of the evaluation object. The evaluation indexes should show the real state of the evaluation object comprehensively, but the more the indexes are, the better the evaluation indexes are, the strong connection with the evaluation object should exist, and the indexes which can cover the main content of the evaluation object and reflect the real information of the evaluation object are selected as much as possible. In addition, the selection of the evaluation index also needs to consider the evaluation cost, so that the index is simplified as much as possible on the basis of meeting comprehensiveness, and the development of actual work is facilitated.

Secondly, the whole index system can have a strong coupling relation with the evaluation purpose, but indexes on the same layer are independent to each other as much as possible, and no coupling relation exists between every two indexes. And eliminating repeated evaluation in the evaluation process, so that the evaluation result shows the real state of the evaluation object.

According to the basic principles of an analytic hierarchy process and a data enveloping method, a direct-current power distribution network index system is established in a layering mode, wherein the direct-current power distribution network index system comprises an input index and an output index, and the direct-current building power distribution system index system is determined as follows by simultaneously referring to relevant standards and technical specifications. The index system comprises three main levels: the direct current power distribution system comprises a target layer (A), a criterion layer (B), and a scheme layer (C), wherein the criterion layer is that the main factors related to energy efficiency in the system composition of the direct current power distribution system of the building group are divided into two types of input indexes and output indexes on the basis of specific application scenes (industry, commerce, residents and the like) and established planning and designing targets. The metric quantities of the criterion layer can be considered from three basic aspects: and finally determining an energy efficiency level index system of the direct-current building power distribution system as shown in the figure 3 according to the system architecture, the control method and the operation characteristics.

According to the determined comprehensive evaluation method for the energy efficiency of the direct-current building power distribution system based on the analytic hierarchy process and the data envelope process, various state quantities and index quantities reflecting the system planning design result and the operation state are divided into an input type and an output type according to the planning design and the mutual relation. The input index is similar to the system input quantity or control quantity in the control theory, and the main characteristic of the method is that the index which can be directly determined or indirectly ensured in the planning stage and has direct correlation and influence on the system energy efficiency level. The output index quantity is similar to the output variable of the system in the control theory, and is characterized in that the specific characteristics of the energy efficiency level of the system are directly reflected as the result of the input control quantity. In order to comprehensively and comprehensively analyze and evaluate the energy efficiency level of a building group direct current power distribution system as far as possible, by combining the analysis evaluation basis in the existing alternating current power distribution system and the main characteristics of the direct current building power distribution system, two parameters, namely comprehensive average line loss rate and single line loss qualification rate, which directly reflect the energy consumption condition of the system are determined in the embodiment to serve as output index quantities, and the two parameters participate in the construction of an energy efficiency comprehensive evaluation system.

Evaluation indexes can be divided into forward indexes and reverse indexes according to the influence of the indexes on the direction of an evaluation target. When the index value is larger, the energy efficiency level of the power distribution network is higher, the index is a forward index and comprises energy storage access position normalization, distributed power supply access position normalization, a lead average section, bus voltage qualification rate, energy storage capacity ratio, converter efficiency, alternating current side power factor, control system stability level, control system economy level and the like; if the index value is larger, the energy efficiency level of the power distribution network is lower, the index is a reverse index, such as the average power supply radius. For the capacity ratio of the distributed power supply and the controllable degree of the building load, when the ratio of the capacity ratio of the distributed power supply does not exceed the allowable ratio, the forward index processing can be carried out.

In this embodiment, the indexes include a line average power supply radius, a line average cross section, an energy-saving wire ratio, a three-phase load unbalance degree, a current harmonic distortion rate, a line load rate, a power factor qualification rate, an energy storage access position validity degree, a distributed power supply access position validity degree, an energy storage capacity ratio, a distributed power supply capacity ratio, a building load controllability degree, a power supply radius and a wire cross section, a bus voltage qualification rate, an alternating current side power factor, a control method stability level, a control method economy level, a converter efficiency, an integrated average line loss rate and a single line loss qualification rate. Specifically, the method comprises the following steps:

(1) Average supply radius of line

The average power supply radius r of the line refers to the ratio of the sum of all power supply radii of the line to the number of lines:

in the formula r _i The power supply radius of the ith single-circuit line is shown, and n is the number of circuit circuits.

(2) Mean cross section of the line

The average cross-sectional area s of the line represents the ratio of the sum of all the line cross-sections to the number of lines:

in the formula s _i The section of the ith single-circuit line is shown, and n is the number of circuit loops.

(3) Energy-saving wire ratio

The energy-saving wire occupation ratio delta represents the proportion of energy-saving equipment to the total number of equipment in all line equipment:

wherein m represents the total number of line devices, m _s Indicating the total number of energy saving devices therein.

(4) Degree of unbalance of three-phase load

The three-phase unbalance degree beta means that three-phase currents (or voltages) in the power system are inconsistent in amplitude, and the amplitude difference exceeds a specified range:

in the formula i _x Representing a phase current, i, in three phases _av The average current is indicated.

(5) Current harmonic distortion rate

The current harmonic Distortion rate refers to the ratio of the Total harmonic effective value of the current to the fundamental effective value, and a performance parameter for characterizing the Distortion degree of a waveform relative to a sine wave in the electrical engineering discipline, and is abbreviated as THD (Total harmonic Distortion). It is defined as the ratio of the rms value of the total harmonic content to the rms value of the fundamental, expressed in percent.

The fourier analysis analyzes the total harmonic distortion rate. According to the theory of fourier analysis, any periodic signal can be regarded as a superposition of a series of sinusoidal signals of different frequencies, amplitudes and phases, including a signal that is the same period as the original signal (fundamental wave) and a sinusoidal signal of higher frequency (harmonic wave):

in the formula I _i Represents a higher harmonic (i)>1),I ₁ Represents the effective value of the fundamental current and s represents the highest harmonic order.

(6) Line load factor

Line load factor a refers to the maximum current i of the line _load Ratio to safety current I:

(7) Power factor qualification rate

The power factor qualification rate gamma refers to the ratio of qualified running time of the system power factor to the total time of the acquisition period in the acquisition period:

wherein, t _q And the qualified running time of the system power factor is represented, and T represents the total time of the acquisition cycle.

(8) Validity of stored energy access position

Different access positions of the energy storage devices have different influences on the loss of the whole power distribution network, and therefore the overall energy efficiency level of the building group direct-current power distribution system is influenced. A simplified low voltage dc distribution network is shown in figure 4. The present embodiment focuses on the objective of saving power and electric quantity from the system, and for simplifying the analysis, two ways of connecting the energy storage device to the dc bus and the distributed power source side in parallel are described below.

(8.1) the energy storage unit is connected in parallel with the direct current bus

When the energy storage device is connected to the dc bus in parallel, for the convenience of loss calculation, each branch in the above figure is replaced by an equivalent resistor, and the current and reference direction of each branch are as shown in fig. 5.

Suppose that the alternating current and the photovoltaic supply power to the direct current load together, and the load fluctuation condition is considered, the energy storage device is in a discharge state at the moment, and the loss of the energy storage branch and the rectifying device is ignored, which is the same as the following. The losses of the whole system are:

wherein, I _j Is the effective value of the current of the jth branch, R _j The same applies below for the equivalent resistance of the jth branch.

(8.2) the energy storage unit is connected in parallel to the distributed power supply side

The energy storage unit access position is selected as the outgoing side of the distributed power generation unit, as shown in fig. 6.

Assuming that the load state is the same as described in (1), the loss of the entire system is

Wherein, I' ₂ ＝I ₂ +I ₅ 。

From the above conclusion, Δ P' > Δ P, that is, the total loss of the whole system with the energy storage device connected in parallel to the photovoltaic power supply side is larger than the total loss generated when the direct current bus is connected. From the viewpoint of reducing the system loss and improving the system energy efficiency, the method (8.1) should be selected. But in order to improve the distributed power quality and the system reliability, the mode (8.2) can meet the requirement. In the actual production field, the consideration can be comprehensively balanced and the selection can be compromised.

Therefore, the access positions of the energy storage devices are different, and the loss of the system can be greatly influenced, so that an evaluation index of the validity of the access positions of the energy storage devices is provided, the evaluation index is defined as the validity of the access positions of the energy storage devices in the direct-current building power distribution network for improving the overall energy efficiency of the system operation, the selection of the index quantity is determined by adopting a method of combining a system simulation analysis result and expert scoring, and the validity level is divided into 3 levels which respectively correspond to 1, 2 and 3 points of the index result. The number 3 indicates that the access position of stored energy can improve the stability of distributed power generation on the basis of improving the distributed utilization rate to the maximum extent, so that the energy efficiency loss caused by system operation fluctuation is reduced; 2, the energy storage units are arranged in the building direct-current power distribution system, so that distributed output fluctuation can be improved to a certain extent or the power taking power of the alternating-current main network can be reduced; the 1 point indicates that the access position of the stored energy in the system has limited capability of providing stable support for the distributed power supply, or the power loss of the energy transmitted through the energy storage path exceeds the expected value.

(9) Distributed power access location validity

For a distributed power generation device in a building group direct current power distribution system, an energy transmission path mainly comprises two parts of load power and return power grid power, and due to the existence of line loss, the loss degree of corresponding transmission power is different due to the difference of access positions of the power generation device, so that the integral energy efficiency level of the system is changed. Therefore, the normative degree of the distributed power generation access positions in the expected operation scene is selected as one of the index quantities for measuring the energy efficiency level of the system. The following description will specifically describe the case where the distributed power generation apparatus has a large influence on the access load side and the grid-connected unit side.

A schematic diagram of a system structure of a distributed power generation device accessing to a unit building load side is shown in fig. 7, under such an architecture condition, by reasonably configuring the capacity of each distributed power source, local consumption of new energy can be realized as much as possible, because the distributed power generation device is closer to the building load and the power of each unit is smaller, the power loss transmitted to the load by distributed power generation is ignored here, and the power circulation between different unit building loads is not considered, the energy loss generated by the distributed power generation device in the system is mainly the return power loss of the distributed power generation device to the power grid, and the following relationships are satisfied:

wherein, I _DG Is the total return current; i is _DGi Outputting the current of the return power grid for the ith distributed power supply; r ₁ The equivalent resistance of the output side line of the grid-connected unit; r _Li The equivalent resistance of the line between the direct current bus and the ith unit building load.

Similarly, when the distributed power supply has a large scale and is directly connected to the grid-connected unit side, the schematic structural diagram of the system is shown in fig. 8.

At this time, the power loss generated by the power of the return power grid output by the distributed power supply can be ignored, the main power loss of the system comes from the load current output by the distributed power supply, and the relation is satisfied:

wherein, I _DG Outputting a load current for the distributed power supply; i is _DGi The current flowing to the ith unit building load for the distributed power supply; r ₁ The equivalent resistance of the output side line of the grid-connected unit; r _Li The equivalent resistance of the line between the direct current bus and the ith unit building load.

From the simplified analysis results, it can be known that due to changes of the system operation state, including changes of the distributed power supply output and changes of the output in the distribution proportion of the load and the backflow power grid, the energy consumption situation generated by the distributed power supply changes, and the change situation and the influence degree of the change situation on the overall energy efficiency level of the system are closely related to the access positions of the distributed power supply. Therefore, an energy efficiency index quantity, namely the validity of the distributed access position, is provided, and is defined as the validity of the access position of the distributed power supply in the direct-current building power distribution system for improving the utilization rate of the distributed power supply. The selection of the index quantity is determined by combining a system simulation analysis result and expert scoring, the effective level is divided into 3 levels which respectively correspond to 1, 2 and 3 points of the index result. The number 3 represents that the access positions of distributed power supplies in the building direct-current power distribution network can achieve that most of the output power is consumed nearly, and the loss of distributed power generation is minimized under the condition that the utilization rate is guaranteed; 2, when the distributed power generation can not be completely utilized by the load in real time, the energy loss of the transmission path (including distributed-load and distributed-energy storage) where the distributed power generation is located is less than or equal to the energy loss of the alternating-current main network loop at the same level; score 1 indicates that the energy loss on the transmission path (including distributed-load and distributed-energy storage) of the distributed power supply is greater than that of the alternating-current main network loop at the same level under the condition of completely absorbing the output due to unreasonable access positions of the distributed power supply.

(10) Energy storage capacity fraction

The input power and the output power are balanced at the moment according to the power balance, i.e. P _out ＝P _in . When no energy is stored, the system output is provided by power plant or spare equipment, with P _load ＝P _G (ii) a When the energy storage system is equipped with energy storage, under the condition of normal load, the energy storage system stores surplus electric energy, when the peak load appears in the system, the energy storage system discharges to realize the balance of power, at the moment, P _Load ＝P' _G +P _ESS Of which is P' _G ＜P _G . Therefore, the energy storage realizes load peak clipping and valley filling, saves electric power, can realize electric quantity saving, and has obvious influence on the whole energy efficiency level of the system, so that the energy storage capacity occupation ratio is selected as one of index quantities of the energy efficiency level of the building group direct current power distribution system, and further analysis and explanation are carried out by combining with a simplified system structure diagram.

Setting the AC side power curve as P in the load fluctuation time period and under the condition of no energy storage ₁ (t) when the energy storage device is equipped, the AC side power curve is P ₂ (t), the difference in the electrical loss between the two modes can be expressed by the following equation

According to the formula, in the load fluctuation stage, the energy storage not only reduces the power loss, but also reduces the electric quantity loss. Thus, the evaluation index of the energy storage capacity ratio is provided. The index represents the ratio of the total capacity of the energy storage equipment to the total capacity of the system for generating power, namely:

order to

Total capacity of electricity generation

According to the system shown in FIG. 9And simplifying a schematic diagram of a topological structure, and the following steps are the same without considering the load flow return of the distributed power supply.

The loss generated in the AC power transmission link is

The loss of electric power in the T period of the load fluctuation is

From the above analysis, it can be seen that under the condition of peak load or short-time power loss, when γ =1, the energy storage device achieves the ideal effect, and the system loss is minimum.

(11) Capacity ratio of distributed power supply

Intuitively, under the condition of fixed load, the power absorbed by the building direct-current power distribution system from the power grid is reduced by the access of the distributed power supply, and further, the line loss of the alternating-current side and the direct-current side of the grid-connected unit is reduced. Secondly, due to the self-output characteristics of the photovoltaic distributed power supplies and the like, the power flow distribution condition and the voltage condition of the power distribution system can be influenced, and the energy efficiency level of the system is further influenced. Therefore, it is necessary to select the capacity occupancy of the distributed power sources in the dc building power distribution system as one of the energy efficiency analysis evaluation indexes for research, and the following briefly analyzes and explains the system structure schematic diagram and the operation state. Like above, regardless of the power flow reversal of the photovoltaic system, a simplified system topology is shown in fig. 10.

In the absence of a photovoltaic power generation system, the total system losses are

Under the same load working condition, the grid connection of the photovoltaic system can directly reduce the transmission capacity of the alternating current side, so that the power and electricity loss in the power transmission link is reduced, and the total loss of the system is

Wherein I' _G ＜I _G Generally, a distributed power supply applied to a low-voltage power distribution system is used for on-site power generation, so that the electric energy consumed in a power transmission link is negligible. Then Δ P > Δ P', the on-site photovoltaic power generation system reduces the overall loss of the power distribution system. Therefore, a distributed power supply capacity ratio evaluation index is provided, wherein the index represents the ratio of the total power generation capacity of the distributed power supply to the total load demand capacity of the system and can be represented by the following formula.

Setting the capacity of the distributed power supply to be

The amplitude of the AC side voltage is V _AC The amplitude of the DC side voltage is V _DC For the input side PWM converter of the AC power network, a conversion relation V is provided _AC ＝mV _DC And m is the modulation degree of the PWM converter. Assuming that the filter capacitance on the DC side is large enough, the DC side voltage can be approximated as U _DC ＝V _DC When the distributed power supply is not connected in the system, the total loss of the system is

After the distributed power supply is connected into the system, the alternating current side current is changed into I' _G The expression is

Distributed power branch current of

Total system loss of

If the PWM converter operates at unity power factor, the loss difference between the merging sequences of the distributed power sources can be expressed as

Order to

Can be obtained that the maximum point thereof appears at

Therefore, when the line length and the modulation degree are constant, the capacity ratio of the distributed power supply is satisfied

And in time, the loss of the system is the lowest, the system loss can be reduced to the maximum extent, and the energy efficiency level of the system is improved.

(12) Controllable degree of building load

As one of the outstanding characteristics of the building direct-current power distribution system, the controllable degree of the building load is higher than that of other medium and low voltage direct-current power distribution networks and the traditional alternating-current power distribution system, and the building constant-power control and demand response control in the building economic optimization control are realized, so that the energy efficiency level and the economic level of the system operation are directly influenced. The controllable degree of the building load is defined as follows:

wherein, P _c Representing groups of buildingsTotal power, P, of interruptible and non-interruptible time-limited loads in a DC distribution system _tot Representing the total power of the load in the system.

Generally, the higher the controllable degree of the load in the system is, the more the stability of the overall operation state of the system can be improved through the response control of the demand side, and the more obvious the economic operation effect is obtained by adopting the system economic optimization control method. However, the controllability of the load is improved in more load converters and switch circuit applications, the efficiency of the hardware structure has a certain influence on the energy efficiency level of the system, and in consideration of the scale and the use characteristics of the building load, the present embodiment determines that the index meets the set upper limit range, configures a building group economic control method, and considers the index as a forward index.

(13) Radius of power supply and cross section of wire

By the formula of resistance

It is known that the power distribution system losses are proportional to the length of the conductor, i.e. the supply radius, and inversely proportional to the section of the conductor. The resistance of the power supply line is directly related to the line loss, so that the overall energy efficiency level of the system is influenced, and therefore, the average power supply radius and the average section of the lead are necessarily listed in an energy efficiency index system. In order to reduce the loss and take the objective practical situation into consideration, the optimal power supply radius and the power transmission conductor with a larger section are selected,

the same is true. For a building direct-current power distribution transformation project, the influence of the factor on energy consumption and energy efficiency needs to be considered, and the following brief analysis and description are provided. In order to accurately obtain the saved electric power before and after the project is implemented, the load working condition is adjusted to be the load working condition after the project is implemented, the active power after the project is implemented is set to be P', and the average power factor is set to be

Then the power loss before the project implementation is calculated under the new condition is:

the power loss after the project was implemented was:

the reduced power loss before and after wire replacement is:

wherein, U _N Rated voltage for the line; p' is the expected maximum active power of the transmission line;

the power factor after the wire replacement; r' is the resistance after the lead is replaced.

(14) Bus voltage qualification rate

The bus voltage qualification rate reflects the proportion of qualified bus voltage duration to the total bus voltage monitoring time in a certain continuous operation time period, namely the ratio of the qualified bus voltage duration to the bus voltage operation time. According to the 'electric energy loss calculation guide rule of the power grid' (DL/T686-1999), the system loss can be divided into variable loss and fixed loss, and the magnitude of the system bus voltage directly influences the overall loss of the system. Too low a voltage results in an increase in variable losses, and too high a voltage will make fixed losses larger. Therefore, the operating voltage range should be reasonably specified in the direct-current building transformation or construction project design scheme, and the bus voltage is maintained by an effective control method, so that the sum of the fixed loss and the variable loss is minimized. In the embodiment, the energy efficiency of the building direct-current power distribution system in long-term operation is considered, so that the bus voltage qualified rate of the system is selected as one of index quantities for energy efficiency analysis and evaluation to be researched.

(15) AC side power factor

For a direct-current building power distribution system, a large number of power electronic devices are adopted in each component unit to realize high controllability of a system power supply, energy storage and load, and harmonic pollution is inevitably generated by the switch control devices, so that the power factor of the alternating-current side of the system is reduced. This results in additional power losses and converter reductions on the ac network side of the upper level of the grid-connected unit and on the building ac loads. Therefore, under the condition that the general direct-current building power distribution system has a grid-connected interface and a certain proportion of alternating-current loads, the loss is increased due to the reduction of the power factor at the alternating-current side, and the energy efficiency level of the system is further reduced. Therefore, the alternating-current side power factor is selected as one of the energy efficiency analysis evaluation indexes of the direct-current building power distribution system.

According to the existing research results, the alternating-current side power factor of the direct-current building power distribution system can be improved through reactive compensation and reasonable design of power supply capacity and distribution conditions, and therefore the overall energy efficiency level of the system is improved. Taking a typical ac power grid input side line compensation method as an example for analysis, under the condition that the output of dc power supplies such as a distributed power supply and energy storage is not considered, the total power loss of a dc building power distribution system can be expressed as:

the reduced power loss before and after the typical reactive compensation method is used can be expressed as:

the reduced power loss can be expressed as:

wherein: q' is the reactive load of the circuit after reactive compensation; u shape _N The rated voltage of a certain voltage class is reduced for the rated voltage of the reactive compensation point; r is the equivalent resistance of all series elements reduced to a certain voltage level; q _C Compensating capacity for the reactive power compensation device; c is reactive economic equivalent; k is the loss rate of the reactive power compensation device; Δ (Δ P) _i ) The power loss is reduced under the ith working condition after reactive compensation; t is _i The operation time of the compensating device in the ith working condition.

(16) Controlling method stability level

For the operation state of a building group direct current power distribution system, the design and the application of the control method have a remarkable influence on the energy efficiency level of the system. Considering both the stability and the economy of the system control method, it is necessary to select it as one of the evaluation indexes of the system energy efficiency level, and the influence on the system energy efficiency level will be specifically described in the following.

The stability of the control method is mainly represented by maintaining the normal operation level of the power distribution system in the face of load disturbance and alternating current main network state change, and is visually represented by that the direct current bus voltage is in a normal range and the system power is balanced. The influence of the stability of the control method on the system energy efficiency is mainly expressed in two levels: firstly, the influence on the visual indexes is achieved; and secondly, in a specific control process, the coordination and coordination of all units are matched with the operation condition. For the former, it is obvious that the stronger the stability performance of the control method is, the more the system bus voltage and power balance is problematic, the shorter the transient process is, each unit converter keeps a normal operation state, and the higher the energy efficiency level of the system is. In the latter case, the simpler the control of the system units involved in the stability control stage of the system is, the more clear the coordination relationship is, the higher the energy efficiency level of the system is, the more the transmission power imbalance among the units will not cause the system to generate circulating power, which will cause extra loss of the unit converter and the transmission line.

Therefore, the stability level of the building group direct current power distribution system control method is selected as a forward index in the system energy efficiency evaluation system to be considered. The method is defined as the capability of keeping the system running stably by a control strategy when the same dynamic scene is faced (including load change, distributed output change, off-grid state switching and the like) under the condition that the composition and the configuration of a hardware unit of the direct-current building power distribution system are determined. The method is determined by combining simulation analysis and expert scoring and is divided into three levels of 1 point, 2 points and 3 points. The control strategies of 3-division unit level, multi-source coordination level and distribution network level all realize quick response at each port in the dynamic process, so that the voltage of a direct-current bus, the distributed output and the transmission power of a converter are kept stable or given change is tracked, and the energy consumption in the dynamic regulation process is reduced to the maximum extent; 2, the division indicates that the local unit level control can realize good dynamic response and ensure the highest operation efficiency of the converter body, but dynamic circulation generated by the cascade connection of the converter or the voltage fluctuation of a direct current bus exceeds a set value due to the defect of the upper level control; a score of 1 indicates that the cell level control has insufficient stability and cannot guarantee that the characteristics of the ports, especially the distributed and load ports, cause extra loss in the dynamic process.

(17) Controlling process economics levels

The impact of the economic level of the system control method on the energy efficiency level of the system will be described with reference to the above analysis of the stability level of the system control method, which is mainly reflected in the economic optimization goal and effect of the control method, and the economic level of the control system includes but is not limited to: the method comprises the following steps of performing operation economy control on each unit of the system, such as charging and discharging current control and energy management of an energy storage unit; the system is controlled in the economy of the whole operation, and the power distribution system and the superior distribution network system are controlled in the economy, including the constant power control of the unit building.

From the above analysis, under the condition that the architecture and configuration in the specific application scenario planning scheme are determined, different control methods have direct influence on the energy efficiency and the economic level of the long-term operation of the system, so the economic level of the control method is selected as a forward index in the system energy efficiency evaluation system to be considered. The method is defined as the improvement level of different economic optimization targets in the uppermost control method to the system energy efficiency under the condition that the application scene is determined, and is determined by combining simulation analysis and expert scoring, and the improvement level is divided into three levels of 1 point, 2 points and 3 points. Wherein 3 denotes that the economic optimization method in the control strategy can realize distributed output; 2, the division indicates that the local unit level control can realize good dynamic response and ensure the highest operation efficiency of the converter body, but the unreasonable configuration of the upper level control causes the phenomenon that dynamic circulation generated by the cascade connection of the converters or the fluctuation of the direct current bus voltage exceeds a set value in the system; a score of 1 indicates that the cell level control has insufficient stability, and the stability of the ports, especially the distributed and load ports, cannot be guaranteed in a dynamic process, resulting in extra loss.

(18) Efficiency of converter

A large number of converters are adopted in the direct-current building power distribution system, so that the efficiency of the converters is directly related to the energy efficiency level of the whole direct-current building power distribution system, and the converters are selected as important indexes for system energy efficiency analysis and evaluation. The operation efficiency of the converter is related to various factors such as the circuit structure of the converter, device model selection, control mode and the like, and the operation loss of the converter is mainly formed by power electronic devices such as a switching tube, a diode and the like, so that simplified equivalent analysis can be performed according to the operation loss.

(19) Comprehensive average line loss rate

And defining the comprehensive average line loss rate as the percentage of the sum of the loss electric energy in each main line in the direct-current building power distribution system to the sum of the electric energy injected by the power grid and the electric energy output by the distributed power supply. The larger the index value is, the more serious the overall loss condition of the power distribution system is, and the lower the energy efficiency level of the system is, so that the index value is a negative index.

(20) Single line route loss yield

On the basis of reflecting the comprehensive condition of energy consumption of the direct-current building power distribution system by adopting the comprehensive average line loss rate, the spatial distribution characteristics of the building load are obvious, and the loss of each line corresponds to a definite load entity, so that the single-line loss qualified rate is adopted as one of output index quantities of an energy efficiency comprehensive evaluation system, the specific control distribution condition of the energy consumption characteristics of the system is reflected, and the excessive influence on the energy efficiency evaluation result caused by the extreme operation condition of a single line or a few lines is balanced as much as possible. The single line loss yield is defined as the proportion of the number of lines with line loss smaller than a set value in a period of time to the total number of lines, and obviously, the larger the index value is, the higher the proportion of each line in the system meeting the line loss requirement is, the lower the loss is, the higher the energy efficiency level is, and the index is a forward index.

By combining the principle analysis and description, the specific settings of the index parameters of the final determination criterion layer 2 are shown in table 1.

TABLE 1 rule layer 2 settings of index parameters

In the step 1), the normalization method comprises the following steps:

according to a grey system association degree analysis (GRAP), firstly, input index parameters of each decision unit are standardized, dimension differences of different indexes are eliminated, and different parameter data are made to be comparable. According to the division and significance of the forward index and the reverse index, the maximum value of the same index and different decision units is selected in the former, the minimum value of different decision units is selected as a reference value in the latter, and the determined index reference value is combined to obtain various index normalization results of each decision unit (design scheme), and finally a normalization matrix is obtained. Element xi of the normalization matrix _i It is defined as follows:

in the formula, x ₀ As a reference index sequence, x _i (k) The index k of the decision unit i is a normalized value of both, and xi is a resolution coefficient, which is generally 0.5.

In the step 2), the calculation of the final weight of the index includes the following steps:

2.1 The contribution degree of a single evaluation index to the energy efficiency of the whole power distribution system in a certain fixed state is obtained by utilizing energy transmission path analysis and a multidimensional function partial differential method, the contribution degrees and weighted values of different index quantities in the same level in an analytic hierarchy process are sequentially determined, and the objectivity and the practicability of the analytic hierarchy process are improved.

2.2 Based on the obtained contribution degree of the index, the final weight is given to the index by using an analytic hierarchy process.

In this embodiment, the traditional way of assigning weights to the analytic hierarchy process is to score according to actual situations and professional experiences by a senior expert, but in this way, human subjective factors are large, and the abundance of the expert experiences and personal preferences directly influence the final evaluation result. In order to eliminate the influence of artificial subjective factors, the contribution degree of a single evaluation index to the energy efficiency of the whole power distribution system in a certain fixed state is obtained by utilizing energy transmission path analysis and a multi-dimensional function partial differential method, and the selected fixed state is required to enable the energy-saving and loss-reducing space to be the largest and is required to meet the actual production condition. And according to the obtained contribution degree of the index, endowing the index with final weight by using AHP, thereby obtaining a weight vector of the DEA input index.

Setting a functional relation of the energy efficiency level of the direct-current power distribution network and a single evaluation index as O = f (p) ₁ ,p ₂ ,...,p _k ) In order to quantify the influence degree of the index change on the energy efficiency level, under the condition that the indexes are mutually independent, partial differential of a multidimensional function at a certain fixed point is used as the contribution degree of the index to the total target, but the fixed point is selected to enable the energy efficiency space of the total target to be maximum or optimal and needs to be combined with the actual production condition. For example, in obtaining the index p ₁ Amount of change Δ p according to the degree of contribution to O ₁ Total energy consumption variable quantity delta O for distribution network ₁ And carrying out curve fitting on the corresponding series of point values. And then, calculating the derivative of the fitting curve, and selecting the derivative value with the negative value and the maximum absolute value as the index contribution degree delta. The specific method is as follows:

wherein p is _h,m Represents an index p _h The value in the m-th calculation state.

When the fitting curve is an increasing linear curve, the actual engineering situation should be considered, and the contribution degree is ensured when the requirements which can be met by the existing engineering project are metAnd (4) determining. Other quantifiable indexes are obtained according to a similar process, and an index contribution degree sequence delta = (delta) is obtained ₁ ,δ ₂ ,...,δ _h ) And the contribution degree of each index is according to the following formula:

normalization is performed to meet comparability requirements. The indexes of the index contribution degree which cannot be solved by using a curve simulation method, such as the normalization of the energy storage access position, the stability level of the control method, the economic level of the control method and the like, can be determined by referring to a method combining the existing example and expert scoring according to an actual planning scheme and application conditions. And finally, obtaining the equivalent contribution of the corresponding index to the energy efficiency level of the direct current building power distribution system, and combining the result with the expert scoring value to jointly construct an AHP judgment matrix M. And (4) carrying out the necessary consistency check step of the AHP process on the M, and judging the reasonability of the structure of the judgment matrix.

In the step 3), the evaluation result is obtained by adopting a data envelope method, and the method comprises the following steps:

3.1 An input index vector X = (X) for a DMU is set ₁ ,x ₂ ,...,x _n ) ^T Corresponding input index weight vector V = (V) ₁ ,v ₂ ,...,v _n ) ^T Output vector index Y = (Y) ₁ ,y ₂ ,...,y _m ) ^T And the corresponding output index weight vector is U = (U) ₁ ,u ₂ ,...,u _m ) ^T Calculating to obtain the energy efficiency evaluation index number of the DMU; wherein, DMU is decision unit;

3.2 According to the energy efficiency evaluation index number of the DMU, obtaining the relative energy efficiency value sequencing of all the DMU, and determining the energy efficiency level according to the sequencing.

Wherein, determining the energy efficiency level according to the ranking specifically comprises: the more forward the ranking, the greater the relative energy efficiency value.

And calculating the relative energy efficiency values of the DMUs according to the above, and finally obtaining the relative energy efficiency value sequence of all the DMUs. The higher the ranking, the greater the relative energy efficiency value, indicating that the energy efficiency level of the DMU is high relative to other DMUs. For a decision unit with low energy efficiency level, specific energy efficiency weak links can be analyzed through checking the scores of all indexes of the lower layer, so that a direction or suggestion is provided for improving the energy efficiency.

The energy efficiency evaluation index number of the DMU is as follows:

In the step 4), the implementation energy efficiency of the power distribution network is improved, and the method comprises the following steps:

4.1 Aiming at the energy efficiency weak link, a power distribution network equipment excavation and submergence efficient system and a two-stage management mode for power distribution network voltage reactive power control are established;

the method comprises the steps of establishing a power distribution network equipment submergence efficient system, optimizing a reactive voltage control strategy, particularly strengthening monitoring work of voltage quality during the period of substation overhaul load transfer, enabling special lines to be not specially arranged, saving power grid investment and improving equipment utilization rate.

In this embodiment, the two-stage management mode of the voltage reactive control of the power distribution network is as follows:

the distribution network line is located the power supply lower circuit end, and to the distribution line of power supply radius overlength, the end user easily appears the low voltage phenomenon in load peak period. In addition, due to the fact that effective management is lacked in switching of the transformer area capacitors, loss of partial branch lines is too large, and economic operation of the power distribution network is affected. Therefore, the voltage of the AVC system of the transformer substation is combined with the reactive compensation equipment of the line side transformer area capacitor, and a two-stage management method for voltage reactive control of the power distribution network is established. The method is characterized in that the low-voltage lines which are prone to appear in the past year are counted, distribution positions of all distribution areas and the allocation conditions of capacitors are arranged in a touch mode, and the voltage and the reactive numerical value of the distribution area are monitored in real time according to a power distribution network monitoring system.

in the period of the overhaul load transfer of the transformer substation, the daily monitoring and analysis of the main transformer side and the line power factor are carried out: firstly, strengthen last busbar line voltage real time monitoring, especially to the terminal low-voltage problem that the longer lead to of contra-rotating supply line power supply radius, the real-time online control transformer substation side reactive compensation equipment switching of control and the accent work that becomes the owner. And simultaneously, in cooperation with a distribution line operation and maintenance unit, the reactive compensation of a capacitor of a distribution area at the line side to the line is made. And secondly, adjusting an AVC reactive voltage control strategy, adjusting AVC nine-region graph boundary parameters, improving the reactive voltage control effect in an abnormal operation mode, controlling the bus voltage and the power factor in an optimal interval and reducing the electric energy loss of the power grid.

4.2 The current limit is dynamically adjusted through the line current-carrying capacity calculation based on meteorological factors, the power distribution capacity is dynamically increased in volume, and the power supply potential is released;

with the economic development, the load of the line is increased, particularly during the full-stop maintenance of a transformer substation, the 10kV line is difficult to transfer, the transfer line exceeds the static thermal stability current-carrying capacity constraint, and the current frequency is out of limit, so that the load limiting measure has to be taken on the premise of ensuring the operation safety of the line. Meanwhile, the air-conditioning load of the urban load center has a gathering increasing situation, and the cable line of the load center is constrained by the power supply capacity and the thermal stability limit, so that the power supply capacity of the line is greatly influenced. And the distribution network line is newly built in the urban area and is limited by the corridor, the construction period is long, the investment cost is high, and the contradiction between the operation safety of the power grid and the load increase in a short period is obvious.

The technology for dynamically increasing capacity of the cable of the relatively mature power transmission line in the power transmission line is used for reference, and the technology is applied to 10kV overhead lines and cable lines of a power distribution network. And the power supply capacity of the distribution line is improved, and the dynamic capacity increase of the distribution line is realized. The static quota of the 10kV distribution network line is the limit capacity which is estimated conservatively under the assumed worst meteorological condition, the value usually ignores the influence of real-time operation working conditions on the thermal stability limit, and the current limit value is generally low, so that the dynamic adjustment of the current quota, the dynamic capacity increase of the distribution capacity and the release of the power supply potential are realized through the line current-carrying capacity calculation based on meteorological factors.

4.3 The method and the system) establish a transformation economy evaluation system based on matching of line parameters, the operation life, the pre-access load characteristics and the series compensation cost, and realize the differential application of the no-load lines of the long-distance distribution network.

The utilization rate of power distribution equipment is low and the operation is not economical in common light-load lines; the idle line is laid aside in idle load all the time, and a large amount of cost is wasted every year from the perspective of equipment depreciation. And for a light no-load line close to the service scrapping age or an overhead line with a smaller line diameter, a reactive compensation device is additionally arranged, the capacity is not obviously improved after the technical transformation, and the recycling economy of the light no-load line is not high. Therefore, a technical transformation economic evaluation system based on matching of line parameters, operation years, pre-access load characteristics and series compensation cost is established. The idle load line differentiation of the long-distance distribution network is realized, the large output of the series compensation technology 'small input', multiple purposes are achieved at one stroke, and the utilization efficiency of the idle load line is improved.

In one embodiment of the present invention, a building power distribution system energy efficiency assessment and improvement system is provided, which includes:

the first processing module is used for normalizing indexes in an energy efficiency index system of the alternating current power distribution system and an energy efficiency index system of the direct current power distribution system and inputting a pre-established building power distribution network comprehensive evaluation model;

the second processing module is used for obtaining the maximum or optimal contribution degree of the single index to a preset total target so as to determine the contribution degrees of different index quantities and further obtain the final weight of the index;

the evaluation module is used for combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result;

and the lifting module is used for lifting the power distribution network implementation energy efficiency according to the evaluation result and improving the utilization efficiency of the no-load line.

In the above embodiment, in the first processing module, the building distribution network comprehensive evaluation model is established by a method combining an analytic hierarchy process and a data envelope process.

In the above embodiment, in the second processing module, the calculation of the final index weight includes:

the method comprises the following steps of solving the contribution degree of a single evaluation index to the energy efficiency of the whole power distribution system in a certain fixed state by utilizing energy transmission path analysis and a multi-dimensional function partial differential method;

The evaluation module is used for obtaining an evaluation result and comprises the following steps:

In the above embodiment, in the promotion module, the promotion of the power distribution network implementation energy efficiency includes:

the two-stage management mode of the voltage reactive control of the power distribution network is as follows:

when the voltage of a station end or a station area exceeds the limit and reactive power is transmitted backwards, early warning is sent out, a power supply service command system is used for sending capacitor switching short messages, and field reactive power compensation equipment management is implemented according to switching instructions;

The current limit is dynamically adjusted, the power distribution capacity is dynamically increased and the power supply potential is released through line current-carrying capacity calculation based on meteorological factors;

The system provided in this embodiment is used for executing the above method embodiments, and for specific flows and details, reference is made to the above embodiments, which are not described herein again.

In the computing device structure provided in an embodiment of the present invention, the computing device may be a terminal, and may include: a processor (processor), a communication Interface (Communications Interface), a memory (memory), a display screen, and an input device. The processor, the communication interface and the memory are communicated with each other through a communication bus. The processor is used to provide computing and control capabilities. The memory comprises a nonvolatile storage medium and an internal memory, wherein the nonvolatile storage medium stores an operating system and a computer program, and the computer program is executed by the processor to realize the energy efficiency evaluation and promotion method of the building power distribution system; the internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The communication interface is used for carrying out wired or wireless communication with an external terminal, and the wireless communication can be realized through WIFI, a manager network, NFC (near field communication) or other technologies. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on a shell of the computing equipment, an external keyboard, a touch pad or a mouse and the like. The processor may call logic instructions in memory to perform the following method: normalizing indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system, and inputting a pre-established building power distribution network comprehensive evaluation model; obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index; combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result; and according to the evaluation result, the implementation energy efficiency of the power distribution network is improved, and the utilization efficiency of the no-load line is improved.

In addition, the logic instructions in the memory may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Those skilled in the art will appreciate that the above-described configurations of computing devices are merely some of the configurations associated with the present application, and do not constitute a limitation on the computing devices to which the present application may be applied, and that a particular computing device may include more or fewer components, or some components may be combined, or have a different arrangement of components.

In one embodiment of the invention, a computer program product is provided, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-described method embodiments, for example, comprising: after indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system are normalized, inputting a pre-established building power distribution network comprehensive evaluation model; obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index; combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result; and according to the evaluation result, the implementation energy efficiency of the power distribution network is improved, and the utilization efficiency of the no-load line is improved.

In one embodiment of the invention, a non-transitory computer-readable storage medium is provided, which stores server instructions that cause a computer to perform the methods provided by the above embodiments, for example, including: after indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system are normalized, inputting a pre-established building power distribution network comprehensive evaluation model; obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index; combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result; and according to the evaluation result, the implementation energy efficiency of the power distribution network is improved, and the utilization efficiency of the no-load line is improved.

The implementation principle and technical effect of the computer-readable storage medium provided by the above embodiments are similar to those of the above method embodiments, and are not described herein again.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A building power distribution system energy efficiency assessment and improvement method is characterized by comprising the following steps:

after indexes in an energy efficiency index system of an alternating current power distribution system and an energy efficiency index system of a direct current power distribution system are normalized, inputting a pre-established building power distribution network comprehensive evaluation model;

obtaining the maximum or optimal contribution of the single index to a preset total target to determine the contribution of different index quantities and further obtain the final weight of the index;

combining the final weight of the index with a data envelope analysis method to obtain a final evaluation result;

and improving the implementation energy efficiency of the power distribution network according to the evaluation result, and improving the utilization efficiency of the no-load line.

2. The method for evaluating and improving the energy efficiency of the building power distribution system according to claim 1, wherein the comprehensive evaluation model of the building power distribution network is established by a method combining an analytic hierarchy process and a data envelope method.

3. The method according to claim 1, wherein the calculating of the index final weight comprises:

4. The method for evaluating and improving the energy efficiency of the building power distribution system according to claim 1, wherein the obtaining of the evaluation result comprises:

5. The building power distribution system energy efficiency assessment and improvement method according to claim 4, wherein said determining energy efficiency levels according to a ranking comprises: the more forward the ranking, the greater the relative energy efficiency value.

6. The method for evaluating and improving the energy efficiency of the power distribution system of the building according to claim 1, wherein the improving the energy efficiency of the power distribution network comprises:

aiming at the weak energy efficiency link, a power distribution network equipment submergence efficient system and a two-stage management mode of power distribution network voltage reactive power control are established;

the current limit is dynamically adjusted through the line current-carrying capacity calculation based on meteorological factors, the power distribution capacity is dynamically increased in volume, and the power supply potential is released;

7. The building power distribution system energy efficiency assessment and improvement method according to claim 6, wherein the two-stage management mode of the distribution network voltage reactive power control is as follows:

in the period of the maintenance load transfer of the transformer substation, daily monitoring and analysis of the power factors of the main transformer side and the line are carried out: strengthening real-time monitoring of the voltage of the upper bus line; and adjusting an AVC reactive voltage control strategy, improving the reactive voltage control effect in an abnormal operation mode, and controlling the bus voltage and the power factor in an optimal interval.

8. A building power distribution system energy efficiency assessment and promotion system, comprising:

9. A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-7.

10. A computing device, comprising: one or more processors, memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods of claims 1-7.