CN107453369B - Intelligent power distribution network optimization power saving and loss reduction system - Google Patents

Intelligent power distribution network optimization power saving and loss reduction system Download PDF

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CN107453369B
CN107453369B CN201710540024.XA CN201710540024A CN107453369B CN 107453369 B CN107453369 B CN 107453369B CN 201710540024 A CN201710540024 A CN 201710540024A CN 107453369 B CN107453369 B CN 107453369B
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transformer
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CN107453369A (en
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范新海
曲毅
王佩玺
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Beijing Tiantai Yihe Technology Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1807—Arrangements for adjusting, eliminating or compensating reactive power in networks using series compensators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
    • H02J2310/50—The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads
    • H02J2310/56—The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads characterised by the condition upon which the selective controlling is based
    • H02J2310/62—The condition being non-electrical, e.g. temperature
    • H02J2310/64—The condition being economic, e.g. tariff based load management
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems
    • Y04S20/222—Demand response systems, e.g. load shedding, peak shaving

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

Intelligent power distribution network optimizes economize on electricity and falls and decreases system includes: the system comprises a power grid flow analysis subsystem, a power distribution network breakpoint optimization system, a power distribution network reconstruction system, a transformer voltage regulation optimization system, a power regulation and power saving system, a substation main reactance optimization system, a substation reactor optimization system, a substation reactive power optimization system and a central system; the intelligent power distribution network optimization power saving and loss reduction system is completely novel, and all parts of the power distribution network are comprehensively analyzed and optimized, so that the comprehensive effect of energy saving and power saving of the whole power distribution network is realized; all subsystems of the power distribution network are specially developed for realizing analysis and optimization of a certain link of a certain part of the power distribution network, and the subsystems can perform operation optimization operation independently.

Description

Intelligent power distribution network optimization power saving and loss reduction system
Technical Field
The invention relates to the technical field of energy-saving systems, in particular to an optimized electricity-saving loss-reducing system for an intelligent power distribution network.
Background
The working state of a large horse-drawn trolley is determined by the working property between the distribution transformer and the electric equipment, the power factor of the distribution transformer is very low, and a large amount of electric energy of a power grid is converted into reactive electric energy to become the main loss of the power distribution network; the loss of the power distribution network consists of line loss and variable loss, wherein the line loss accounts for 5-7% of the total electric quantity, and the variable loss accounts for 18-20% of the total electric quantity;
under the present circumstances, industries increasingly pay attention to the essence and effect of power saving, and a power supply system of a power department considers whether the loss and energy born by the power supply system are reduced or not, so that the power supply cost of the power supply department is reduced to the greatest extent. In a power utilization enterprise, how to use electric energy more scientifically and reasonably is achieved, the power consumption loss and waste of the enterprise are reduced to the maximum extent, the production cost is reduced, most of existing energy-saving products are products with strong pertinence, for example, a street lamp electricity-saving device, a fan electricity-saving device, an air conditioner electricity-saving device, a motor electricity-saving device and the like adopt a principle that an effective load can be used to the maximum power at which voltage position in the operation process, for example, if the voltage of the street lamp electricity-saving device is 220 volts, the street lamp can work normally only with 200 volts actually, the extra 20 volts are wasted, and at this time, the voltage is controlled on 200 only.
Disclosure of Invention
In order to solve the technical problems, the system for optimizing power saving and loss reduction of the intelligent power distribution network aims at using a high-voltage transformer, and achieves the purpose of saving power by changing the iron loss of the high-voltage transformer, namely changing the tap gear of the transformer, so that the saved power proportion is greatly different from the saved power proportion of other power saving equipment; the concept of saving power of the automatic loss reduction system actually saves loss, namely the power of the system; if the power consumption is not changed or saved, the power-stealing behavior is not completed, the more the power consumption is saved, the better the power-saving effect is, so the automatic loss-reducing system is a combination of the national power consumption policy and the high and new technology;
the intelligent power distribution network optimization power saving and loss reduction system is completely novel, and all parts of the power distribution network are comprehensively analyzed and optimized, so that the comprehensive effect of energy saving and power saving of the whole power distribution network is realized; each subsystem is specially developed for realizing the analysis and optimization of a certain link of a certain part of the power distribution network, and can independently perform operation optimization operation;
the no-load loss, i.e. the iron loss, in the transformer loss mainly occurs in the lamination of the transformer core, and is caused by the fact that alternating magnetic lines of force pass through the iron core to generate magnetic hysteresis and eddy current; according to real-time dynamic data of active power P, reactive power Q, total power S and power factor COS phi of the primary side and the secondary side of the transformer, subtracting data of electric quantity of the secondary side from electric quantity data of the primary side at the same moment to give an actual generating value of electric quantity loss of the transformer, dividing the actual generating value by the data of the corresponding primary side, and calculating unit loss rate of each electric quantity parameter;
intelligent power distribution network optimizes economize on electricity and falls and decreases system includes: the system comprises a power grid flow analysis subsystem, a power distribution network breakpoint optimization system, a power distribution network reconstruction system, a transformer voltage regulation optimization system, a power regulation and power saving system, a substation main reactance optimization system, a substation reactor optimization system, a substation reactive power optimization system and a central system;
furthermore, transformer energy-saving management software and an electric charge accounting subsystem are arranged in the central system;
further, the power flow analysis subsystem: the system is a most basic subsystem of an intelligent power distribution network optimization power saving and loss reduction system and is mainly used for calculating all operation states of the whole power distribution network; for calculating the distribution of voltage and power;
as an illustration, current system load flow calculation is the main method of steady state analysis of the power system, and is the most widely, basic and important calculation used in the analysis; the rationality, economy, safety and reliability of the system operation mode can be analyzed and evaluated through calculation, and the task of the system is to determine the operation state of the whole system according to given operation conditions and a network structure, such as the amplitude and phase angle of voltage on each bus, power distribution and power loss in a network and the like; the algorithm of the power flow calculation of the power system is mainly carried out based on an improved Newton method and a P-Q decomposition method; providing basic state data and prediction data for energy conservation optimization of other subsystems;
further, the power distribution network breaking point optimizing system comprises: the system is an important component of the automation of a single power distribution line and an important measure for the safe and economic operation of the whole system;
the method is formed by carrying out deep research and modeling on reconstruction methods of closing and opening of various breaking points through retrospective analysis of history and development current situation of the power distribution network breaking point optimization, and finally designing; in any power distribution network, an optimal network structure theoretically exists, and under the optimal structure, the coordination of the operating voltage, the network loss and the load balance of each load point is superior to other possible schemes; when the load changes, the optimal structure also changes, and the optimal structure is calculated, so that the network operates in an optimal state, which is the main content of the optimization research of the breaking points of the power distribution network; the distribution network breakpoint optimization can also be called distribution network configuration, or distribution network feeder configuration and distribution network feeder reconstruction;
further, the power distribution network reconfiguration system: the reconstruction of the power distribution network is to select a power supply path of a user by changing the combination state of all section switches and interconnection switches of each branch line of the full distribution network, so as to achieve the purposes of reducing the network loss, eliminating overload, balancing load and improving the voltage quality;
furthermore, the voltage regulation optimization system of the transformer aims at improving the voltage qualification rate and reducing the active loss of the network;
as an example, a distribution transformer has a minimum of 3 high-voltage operating steps (high-voltage tap changers) namely: positive 5% of rated voltage, negative 5% of rated voltage and rated voltage;
the iron loss of the transformer is generally regarded as a constant parameter (static loss), and in fact, the iron loss changes greatly when the voltage changes, and the rule of the transformer gear change pair and energy saving is found as follows: when the voltage rises by 5%, the iron loss increases by 20%, and the copper loss decreases by 9%. At this time, the line loss decreases with the rise of the voltage (dynamic loss);
further, the power-rate-adjusting power-saving system can reduce the loss of the transformer by improving the power factor (namely, the power rate) of the transformer; the intelligent production and distribution controller installed on the low-voltage side of the distribution transformer is used for dynamically compensating the transformer and automatically adjusting the force rate, so that over-compensation and under-compensation are avoided, the force rate of the transformer is effectively improved, and the loss of the transformer is reduced;
according to case data statistics implemented by the power regulation rate, a power regulation rate electricity-saving technology is implemented, so that the loss of a distribution transformer can be greatly reduced, electricity is saved, meanwhile, the compensation process of a production and distribution intelligent controller is fed back to a central server in real time, the central server can master the process of power regulation at any time, intelligent power grid compensation is realized, and electricity and energy saving is realized;
further, the main reactance optimization system of the substation: according to the characteristics of a power distribution network of an actual oil field enterprise, under a relatively stable load level, the electrical parameter data of a sensor and main transformer equipment of a substation are transmitted to a central system in real time, and the central system changes the operation of a main transformer into multiple modes through load flow calculation to perform load flow calculation, so that a solution of an optimal operation mode is obtained and proposed;
further, the electric reactor optimization system of the electric substation: the reactor can absorb the redundant line charging power of the power grid, improve the running voltage of the power grid during the low-valley load, reduce the phase-entering running depth of power generation and improve the running performance of the power grid, but the reactor of the substation of an enterprise has larger energy-saving space; entering a central system for calculation according to real-time electric parameters of the substation and factory parameters of the electric reactor, so that an electric reactor optimization scheme can be obtained, and a solution of the most energy-saving and optimized electric reactor operation mode is realized;
further, the reactive power optimization system of the substation: the reactive compensation equipment of the transformer substation mainly comprises a parallel capacitor compensation device, a series capacitor compensation device and a static compensator; a high-voltage transformer substation usually adopts a circuit breaker to switch a reactive compensation device and a reactive static compensation device; the central system can monitor the load condition and the stable condition of the power grid in real time, so that the load flow is calculated by reactive compensation of the substation, an optimal reactive compensation optimization scheme is obtained, and scientific and reasonable compensation is realized. (ii) a According to the load flow calculation data analysis of the reactive power optimization of the central system, the substation can implement a reactive power compensation optimization scheme at any time, so that energy can be greatly saved;
further, the functions and design principles of the production and distribution intelligent controller and the transformer energy-saving management software are as follows:
the method mainly aims to realize the optimization of a transformer end, keep the power supply stable and keep the communication state return of the transformer and the transformer energy-saving equipment;
the working state of the large horse-drawn trolley is determined by the working property between the production and distribution intelligent controller and the electric equipment, the power factor of the distribution transformer is very low, and a large amount of electric energy of a power grid is converted into reactive electric energy to become main loss of the power distribution network.
The loss of the power distribution network consists of line loss and variable loss, wherein the line loss accounts for 5-7% of the total electric quantity, and the variable loss accounts for 18-20% of the total electric quantity;
the production and distribution intelligent controller is a product developed aiming at the loss of a power distribution network, is a power-saving product produced aiming at different operation data of a distribution transformer, can reduce the loss of the power distribution network, and can increase the capacity of the distribution transformer;
as an example, the intelligent production and distribution controller can be used as a remote control system, so that the loss of the network can be more scientifically and reasonably reduced by remotely correcting data according to the wirelessly acquired real-time data;
further, the core function design requirement of the system is as follows:
1. the numerical values of the total network loss and other parameters of each line of the power distribution network in a multi-state can be calculated;
2. the loss reduction scheme of each power line can be quantitatively provided;
3. the three functions can be optimally combined through the disconnection state of the switch, and can be reduced through disconnection optimization
The low network loss percentage is not lower than 3 percent;
furthermore, the intelligent power distribution network optimized power-saving loss-reducing system takes a secondary substation as a unit, all 10kV outgoing lines, switches and distribution transformers are in a calculation range, and the design values of load nodes calculated by the intelligent power distribution network optimized power-saving loss-reducing system are within 400;
furthermore, the transformer energy-saving management software establishes a dynamic database of each parameter according to the calculation result (the unit loss rate of each electric quantity parameter is calculated), calculates the minimum value of each parameter in the economic operation state of the transformer, and outputs a control or alarm signal after the difference value exceeds a certain range, thereby realizing the real-time control of the transformer loss; the running operation of the transformer can meet the infinite approach to the optimization of economic running parameters, thereby realizing the effects of increasing the yield, saving energy and reducing consumption; the method provides reliable basis for scientific calculation and power supply of power supervisor personnel and higher quality of power grid operation quality.
In the big data era, problems existing in enterprises can be rapidly solved by using big data analysis; how to reduce the loss of the oil field distribution network, the big data plays an important role; the intelligent power distribution network optimization power saving and loss reduction system provides more valuable data information and analysis conclusion after acquiring, storing, managing, analyzing, processing and processing big data;
effective data required by the intelligent power distribution network optimization power saving and loss reduction system are mainly divided into three types:
firstly, the type, capacity, iron loss and copper loss of a main distribution transformer of a distribution network, and the type, length, resistance, reactance and other equipment parameters of a line conductor;
secondly, running states of transformers of the power distribution network and closed state parameters of the breaking switches;
thirdly, operating parameters of the power distribution network such as active electric quantity, reactive electric quantity, current, voltage and the like; the power distribution system has the characteristics of an annular structure and open-loop operation. The power distribution system comprises a large number of normally closed disconnecting switches and a small number of normally open disconnecting switches. Under normal operating conditions, the distribution dispatcher periodically (e.g., seasonally) performs a disconnecting link operation to adjust the network structure (reconfigure the network). Through network reconstruction, on one hand, the load is balanced, the overload is eliminated, and the quality of the power supply voltage is improved; on the other hand, the network loss is reduced, and the economical efficiency of the system is improved. And under the condition of a fault, closing some normally-open disconnecting switches and isolating the fault branch. And opening some normally-closed disconnecting switches simultaneously to make the system maintain an open-loop operation state and transfer all or part of the load of the fault branch to another feeder line or another branch of the same feeder line. Therefore, the network reconfiguration is an important means for improving the safety and the economy of the power distribution system;
the optimization objective function of the network reconstruction of the intelligent power distribution network optimization power saving loss reduction system comprises the following steps:
1. the stability and the reliability of the system are improved, so that the system can carry more loads, and the possibility of load shedding is reduced. A typical objective function is:
Figure GDA0002479916980000061
in the formula NPIs the sum of the number of system load points;
Laviis the annual average load at load point i;
Luithe annual outage time for load point i;
r is the state of all interval switches in the network.
There are generally two ways to improve system reliability: firstly, the reliability performance of each element of a composition system is improved; secondly, the redundancy of the system is increased; however, both methods require increased investment and are not very economical; the reconstruction of the power distribution network can improve the reliability of the system under the condition of not increasing investment; further, there are two types of methods for evaluating the reliability of the power distribution network: one is analytical method, and the other is simulation method; the analytic method is to evaluate and calculate the expected outage events one by one to finally obtain the reliability indexes of the user and the system; the analytic method is simple in principle and accurate in model, and is widely used for reliability evaluation of the radiation type power distribution network; however, when the structure of the power distribution system is complicated, the calculation is complicated. A minimum path method commonly used for reliability evaluation of a power distribution network belongs to an analytical method, simultaneously considers the influence of element faults on the minimum path and element faults on non-minimum paths on load point reliability indexes, can find out weak links of the network, and is a very effective algorithm; the simulation method is used for evaluating the reliability index by simulating the actual condition of the service life process of the element and observing the simulation process for a plurality of times, and is suitable for calculating with a complex system, and even is the only feasible solving method in some specific occasions;
2. the method takes the shortest fault recovery time and the smallest power failure range as an objective function, and the typical objective function is as follows:
Figure GDA0002479916980000071
in the formula yi，ziIs the state of the switch and tie switch; a isiIs a weight coefficient; the power supply of the blackout area is recovered to the maximum extent, meanwhile, the overload of the non-blackout area is not caused, the operation is the simplest and the most convenient, and the problem of the reconstruction of the power distribution network is solved. In the past, Expert System (ES) methods were mostly used. However, since the ES cannot handle special cases that have not been encountered in the knowledge acquisition process, it is difficult to cover all failure modes and operation modes; the workload of knowledge acquisition is large, and some knowledge is not easy to express in a regular form; the optimal solution cannot be guaranteed, etc. This enables application of the ESTo a limit;
various algorithms are currently found in the literature. 3 switch indexes containing voltage drop and line parameters are defined, and fault recovery is realized through calculation of the switch indexes. And providing a power distribution network fault recovery reconstruction model comprehensively considering the minimum switching operation times and the minimum network loss. However, the regional power failure recovery problem is a multi-objective, multi-constraint and discrete optimization problem, and the ES and conventional optimization can not be well solved.
3. Load is uniformly distributed, equipment overload is avoided, and the safety and the power supply quality of a power grid are improved: a typical objective function is:
Figure GDA0002479916980000081
Figure GDA0002479916980000082
in the formula, LBi，LBsysLoad balancing indexes of the branch and the system respectively;
Si，Si maxpower flowing through the branch and capacity of the branch, respectively; n isbThe system is a total branch tree.
Due to the rapid change of the load and the lag of the power construction, the load distribution of the power distribution network is greatly unbalanced, thereby bringing great harm, such as increasing the energy loss of the system, influencing the electric energy quality of the system and increasing the risk of overload of the system. There are two main ways to achieve load balancing: firstly, load transfer is carried out among feeder lines of a system level; and secondly, the interphase load exchange of the feeder line level is carried out. A mixed integer nonlinear optimization model is provided and decomposed into two submodels of transformer load balancing and feeder load balancing. However, the decomposition makes the capacity of the feeder line uncertain, and an optimal solution cannot be obtained. A linear integer programming model of network reconstruction is provided for the load balance problem, the objective function and the constraint condition of the problem are accurately represented by a mathematical analysis expression, and the global optimal solution is sought by an analytical method. A new load balancing index is proposed and applied to evaluate the load balancing of the network. A load balancing algorithm for a three-phase unbalanced distribution network is provided. The branch load balancing factors and the overall load balancing factors of the system are used to determine the load level of the system and the capacity of the system.
4. And the active power loss of the system is minimized. A typical objective function is:
minPloss
currently, most of the literature on power distribution network reconfiguration aims at minimizing the real power. However, the load on each node in an actual power distribution system varies from time to time, and the optimal configuration aimed at minimizing the active power loss is not necessarily fixed, and it changes from time to time, resulting in frequent switching operations, which is uneconomical and impractical. Therefore, a practical scheme for minimizing the active power loss is to select a load at a specific time within a specific time period as a calculation load, usually select a peak load, and then propose an optimization scheme of switching operation for minimizing the active power loss in this representative state, so as to complete network reconfiguration. Because an approximate scheme is adopted, the real minimization of the active loss of the system is not realized at the moment of non-peak load, so that a real optimal solution cannot be obtained.
5. The typical objective function for a given period of time (one day, one week or one quarter) with minimal system energy loss is:
Figure GDA0002479916980000091
in the formula cosTSWIs the operating cost of the switch.
For ease of calculation, a staircase curve is typically used to approximate the actual continuous load curve of the replacement power distribution system while ignoring fluctuations in load over a small period of time (one hour). The essence of the method is to discretize continuous variables, pay attention to the variation trend and ignore small variable quantities, and the purpose is to save energy and simplify calculation. It ensures that the system energy consumption over a given time period is minimal. The method is characterized in that the reduction of the electric energy loss is taken as an objective function of network reconstruction, the former adopts a simulated annealing method to solve, but because a large number of multilevel switch exchanges are needed, the calculated amount is large; the latter adopts genetic algorithm to solve, and the main shortcoming of the method is that different initial gene strings are selected to have different optimization results.
At present, the idea of online monitoring the state of the distribution network switch in the industry is mostly focused on monitoring the internal contact, and whether the internal mechanical contact of the switch is contacted or not is monitored by using a certain technology to judge the opening and closing of the switch. Due to the fact that the types and the models of the switches are various, the switches are required to be modified and different monitoring modules are developed aiming at different switches, and therefore labor is wasted and the cost is increased. Based on the situation, the idea is determined to be changed, and the switch state is judged by using a switch two-end state monitoring method. The principle is that the current-voltage state measuring technology is utilized to monitor the current-voltage change conditions at two ends of the switch to judge the opening and closing of the switch. The method has the advantages that only the state change of the current and the voltage on the two sides of the switch needs to be measured, and the type, the model and the health state of the switch do not need to be concerned. The current and voltage detection unit has the advantages of unified development work, accurate judgment and convenient installation.
The communication type switch inductor is hung near a power line switch and mainly comprises a detection circuit, a trigger circuit, a wireless transmission circuit module, a power circuit and the like. The wireless communication type switch inductors are only one group. Can be directly installed and disassembled in a live way.
Further, a distribution network power flow optimization algorithm: the method for reducing the line loss of the breaking point optimization algorithm platform in the power distribution system is more and more generally concerned and emphasized. The distribution network has the characteristics of closed-loop design, open-loop operation, has a large amount of normally closed section switches and a small amount of normally open contact switches in the distribution lines, and this makes can change distribution network's power supply direction and structure through the state that opens and shuts of transform section switch and contact switch.
Theoretically, the breaking point optimization has an optimal structure, so that the line loss is minimized. The purpose of the power distribution network breakpoint optimization is to seek an optimal power supply mode which minimizes line loss and meet the actual operation requirement. The breaking point optimization can utilize the characteristics of the power distribution network to carry out network optimization, does not need additional hardware investment, reduces the network loss, and can balance the load and improve the voltage quality, thereby being an important means for controlling and operating the power distribution system and also being an important content of the power Distribution Management System (DMS).
Mathematically, the break point optimization belongs to the nonlinear combination optimization problem, and as the system scale increases, the traditional mathematical programming method is adopted to generate the 'combination explosion' problem. At present, methods for solving the breakpoint optimization mainly include a branch exchange algorithm, an optimal flow pattern algorithm, and intelligent algorithms such as SA and GA. The breaking point optimization currently used by people is a novel complex algorithm combining the advantages of a branch exchange algorithm, an optimal flow pattern algorithm and SA and GA algorithms, and the breaking point optimization algorithm has good global optimization capability and relatively small calculation amount. The method is a heuristic search method for expanding the neighborhood, and is also a successful application of artificial intelligence in a combined optimization algorithm. The method adopts effective measures to jump out the local optimal point with higher probability, thereby having strong global optimization performance.
The principle process of our breaking point optimization algorithm: and switching on the interconnection switch with the maximum voltage difference at the two ends to form a ring network in the power distribution network, and switching on a normally closed section switch in the ring network to restore the power distribution network to be radial, thereby balancing the load of each branch and reducing the network loss. These operations are continued until there are no more switches in the network that can reduce the network loss. Many studies have been made on the selection of the interconnection switch and the switch to be opened in the corresponding ring network. The network loss variation caused by switch exchange is approximately calculated by using a method of simplifying a power flow equation and neglecting voltage influence (Ui is approximately equal to 1pu) and a method of heuristic estimation in advance, the maximum network loss variation corresponding to each interconnection switch exchange is calculated at the same time, corresponding switch exchange is executed according to the maximum network loss variation, the calculation efficiency of a branch exchange algorithm is improved to a certain extent, and a simple algorithm of maximum loss reduction switch exchange is determined;
after the device of the intelligent power distribution network optimizing power-saving loss-reducing system is installed, the existing power factor can be improved to 0.75 from 0.37 through the force adjusting rate (power factor), and the efficiency is improved by more than one time. The loss reduction rate of active power is close to 50%, and the loss reduction rate of reactive power is 40%. The power regulation rate saves electricity, 6-10% of the total electric quantity can be saved, and the voltage regulation optimization system aims at improving the voltage qualification rate and reducing the network active loss;
has the advantages that:
1. the intelligent power distribution network optimized power-saving loss-reducing system provides an optimal voltage-regulating power-saving scheme by utilizing production and distribution intelligent controllers and related power professional software which are installed on lines mainly according to the model, capacity, active electric quantity, reactive electric quantity, distribution transformer secondary voltage and distribution transformer primary voltage data of all transformers on an oil field distribution line. The voltage regulation and electricity saving can save 0.8-1.44% of the total electric quantity.
2. The production and distribution intelligent controller is a product developed aiming at the loss of a power distribution network, is a power-saving product produced aiming at different operation data of a distribution transformer, can reduce the loss of the power distribution network, and can increase the capacity of the distribution transformer; through many years's experiments, neotype product can regard production distribution electric intelligent control ware as long-range control system to according to the real-time data of wireless collection, through long-range data correction that carries out, carry out the network more scientifically and reasonably and reduce the loss.
3. Enabling entrepreneurs to know the electricity utilization conditions of all production links. The power supply side taps of the transformer in the factory are optimized and adjusted according to the corresponding gear when the total electric charge expenditure is minimum by checking among branch cars, and the power supply side taps of the distribution transformer of the personnel department in the factory are optimized and adjusted to implement the whole-factory power saving and consumption reduction), thereby scientifically and reasonably guiding the power consumption and maximally reducing the power consumption loss of enterprises. And an omnibearing and practical power saving scheme is provided for a user.
4. The breaking point optimization system is an important branch of power distribution network reconstruction. In any distribution network, an optimal network structure theoretically exists, and under the optimal structure, the coordination of the operation voltage, the network loss and the load balance of each load point is superior to other possible schemes. When the load changes, the optimal structure also changes, the optimal structure is calculated, and the network operates in an optimal state, which is the main content of the optimization research of the breaking points of the power distribution network. The power distribution network breakpoint optimization is also called power distribution network configuration, or power distribution network feeder configuration and power distribution network feeder reconstruction. The reconstruction of the power distribution network is to select a power supply path of a user by changing the combination state of the section switch and the interconnection switch, so that the aims of reducing the network loss, eliminating the overload, balancing the load and improving the voltage quality are fulfilled. The breakpoint optimization can reduce the total power by 2-6%.
5. Increasing the power factor (power rate) of the transformer reduces the losses of the transformer. The intelligent power saver arranged on the low-voltage side of the distribution transformer is used for dynamically compensating the transformer, automatically adjusting the power rate, effectively improving the power rate of the transformer and reducing the loss of the transformer, and the power-saving technology of the power regulation rate is implemented according to case data statistics of the power regulation rate implementation, so that the loss of the distribution transformer can be reduced by about 50%. About 8-10% of the total charge.
Drawings
FIG. 1 is an exemplary diagram of the design power saving principle relationship of the optimized power saving and loss reduction system of the intelligent power distribution network
FIG. 2 is an exemplary design diagram of the service process of the transformer voltage regulation optimization system of the intelligent distribution network power saving optimization and loss reduction system of the present invention
FIG. 3 is a schematic diagram of an exemplary design of a production distribution intelligent controller of the intelligent power distribution network optimizing power saving and loss reduction system of the present invention
FIG. 4 is a block diagram illustrating exemplary hardware functions of the power rate adjusting and power saving system of the smart distribution network optimized power saving and loss reduction system of the present invention
FIG. 5 is a schematic diagram illustrating a service flow of the power-rate-adjusting power-saving system of the smart distribution network optimized power-saving loss-reducing system of the present invention
FIG. 6 is a flowchart of a power distribution network reconfiguration calculation algorithm of the intelligent power distribution network optimization power saving and loss reduction system of the present invention
Detailed Description
Next, referring to fig. 1 to 5, the system for optimizing power saving and loss reduction of the intelligent power distribution network is a completely novel type, and all parts of the power distribution network are optimized through comprehensive analysis, so that the comprehensive effect of energy saving and power saving of the whole power distribution network is realized; each subsystem is specially developed for realizing the analysis and optimization of a certain link of a certain part of the power distribution network, and can independently perform operation optimization operation;
the no-load loss, i.e. the iron loss, in the transformer loss mainly occurs in the lamination of the transformer core, and is caused by the fact that alternating magnetic lines of force pass through the iron core to generate magnetic hysteresis and eddy current; according to real-time dynamic data of active power P, reactive power Q, total power S and power factor COS phi of the primary side and the secondary side of the transformer, subtracting data of electric quantity of the secondary side from electric quantity data of the primary side at the same moment to give an actual generating value of electric quantity loss of the transformer, dividing the actual generating value by the data of the corresponding primary side, and calculating unit loss rate of each electric quantity parameter;
intelligent power distribution network optimizes economize on electricity and falls and decreases system includes: the system comprises a power grid flow analysis subsystem, a power distribution network breakpoint optimization system, a power distribution network reconstruction system, a transformer voltage regulation optimization system, a power regulation and power saving system, a substation main reactance optimization system, a substation reactor optimization system, a substation reactive power optimization system and a central system;
furthermore, transformer energy-saving management software and an electric charge accounting subsystem are arranged in the central system;
further, the power flow analysis subsystem: the system is a most basic subsystem of an intelligent power distribution network optimization power saving and loss reduction system and is mainly used for calculating all operation states of the whole power distribution network; for calculating the distribution of voltage and power;
as an illustration, current system load flow calculation is the main method of steady state analysis of the power system, and is the most widely, basic and important calculation used in the analysis; the rationality, economy, safety and reliability of the system operation mode can be analyzed and evaluated through calculation, and the task of the system is to determine the operation state of the whole system according to given operation conditions and a network structure, such as the amplitude and phase angle of voltage on each bus, power distribution and power loss in a network and the like; the algorithm of the power flow calculation of the power system is mainly carried out based on an improved Newton method and a P-Q decomposition method; providing basic state data and prediction data for energy conservation optimization of other subsystems;
further, the power distribution network breaking point optimizing system comprises: the system is an important component of the automation of a single power distribution line and an important measure for the safe and economic operation of the whole system;
the method is formed by carrying out deep research and modeling on reconstruction methods of closing and opening of various breaking points through retrospective analysis of history and development current situation of the power distribution network breaking point optimization, and finally designing; in any power distribution network, an optimal network structure theoretically exists, and under the optimal structure, the coordination of the operating voltage, the network loss and the load balance of each load point is superior to other possible schemes; when the load changes, the optimal structure also changes, and the optimal structure is calculated, so that the network operates in an optimal state, which is the main content of the optimization research of the breaking points of the power distribution network; the distribution network breakpoint optimization can also be called distribution network configuration, or distribution network feeder configuration and distribution network feeder reconstruction;
further, the power distribution network reconfiguration system: the reconstruction of the power distribution network is to select a power supply path of a user by changing the combination state of all section switches and interconnection switches of each branch line of the full distribution network, so as to achieve the purposes of reducing the network loss, eliminating overload, balancing load and improving the voltage quality;
furthermore, the voltage regulation optimization system of the transformer aims at improving the voltage qualification rate and reducing the active loss of the network;
as an example, a distribution transformer has a minimum of 3 high-voltage operating steps (high-voltage tap changers) namely: positive 5% of rated voltage, negative 5% of rated voltage and rated voltage;
the iron loss of the transformer is generally regarded as a constant parameter (static loss), and in fact, the iron loss changes greatly when the voltage changes, and the rule of the transformer gear change pair and energy saving is found as follows: when the voltage rises by 5%, the iron loss increases by 20%, and the copper loss decreases by 9%. At this time, the line loss decreases with the rise of the voltage (dynamic loss);
further, the power-rate-adjusting power-saving system can reduce the loss of the transformer by improving the power factor (namely, the power rate) of the transformer; the intelligent production and distribution controller installed on the low-voltage side of the distribution transformer is used for dynamically compensating the transformer and automatically adjusting the force rate, so that over-compensation and under-compensation are avoided, the force rate of the transformer is effectively improved, and the loss of the transformer is reduced;
according to case data statistics implemented by the power regulation rate, a power regulation rate electricity-saving technology is implemented, so that the loss of a distribution transformer can be greatly reduced, electricity is saved, meanwhile, the compensation process of a production and distribution intelligent controller is fed back to a central server in real time, the central server can master the process of power regulation at any time, intelligent power grid compensation is realized, and electricity and energy saving is realized;
further, the main reactance optimization system of the substation: according to the characteristics of a power distribution network of an actual oil field enterprise, under a relatively stable load level, the electrical parameter data of a sensor and main transformer equipment of a substation are transmitted to a central system in real time, and the central system changes the operation of a main transformer into multiple modes through load flow calculation to perform load flow calculation, so that a solution of an optimal operation mode is obtained and proposed;
further, the electric reactor optimization system of the electric substation: the reactor can absorb the redundant line charging power of the power grid, improve the running voltage of the power grid during the low-valley load, reduce the phase-entering running depth of power generation and improve the running performance of the power grid, but the reactor of the substation of an enterprise has larger energy-saving space; entering a central system for calculation according to real-time electric parameters of the substation and factory parameters of the electric reactor, so that an electric reactor optimization scheme can be obtained, and a solution of the most energy-saving and optimized electric reactor operation mode is realized;
further, the reactive power optimization system of the substation: the reactive compensation equipment of the transformer substation mainly comprises a parallel capacitor compensation device, a series capacitor compensation device and a static compensator; a high-voltage transformer substation usually adopts a circuit breaker to switch a reactive compensation device and a reactive static compensation device; the central system can monitor the load condition and the stable condition of the power grid in real time, so that the load flow is calculated by reactive compensation of the substation, an optimal reactive compensation optimization scheme is obtained, and scientific and reasonable compensation is realized. (ii) a According to the load flow calculation data analysis of the reactive power optimization of the central system, the substation can implement a reactive power compensation optimization scheme at any time, so that energy can be greatly saved;
further, the functions and design principles of the production and distribution intelligent controller and the transformer energy-saving management software are as follows:
the method mainly aims to realize the optimization of a transformer end, keep the power supply stable and keep the communication state return of the transformer and the transformer energy-saving equipment;
the working state of the large horse-drawn trolley is determined by the working property between the production and distribution intelligent controller and the electric equipment, the power factor of the distribution transformer is very low, and a large amount of electric energy of a power grid is converted into reactive electric energy to become main loss of the power distribution network.
The loss of the power distribution network consists of line loss and variable loss, wherein the line loss accounts for 5-7% of the total electric quantity, and the variable loss accounts for 18-20% of the total electric quantity;
the production and distribution intelligent controller is a product developed aiming at the loss of a power distribution network, is a power-saving product produced aiming at different operation data of a distribution transformer, can reduce the loss of the power distribution network, and can increase the capacity of the distribution transformer;
as an example, the intelligent production and distribution controller can be used as a remote control system, so that the loss of the network can be more scientifically and reasonably reduced by remotely correcting data according to the wirelessly acquired real-time data;
further, the core function design requirement of the system is as follows:
1. the numerical values of the total network loss and other parameters of each line of the power distribution network in a multi-state can be calculated;
2. the loss reduction scheme of each power line can be quantitatively provided;
3. thirdly, the optimal combination can be carried out through the disconnection state of the switch, and the percentage of the network loss can be reduced by not less than 3% through disconnection optimization;
furthermore, the intelligent power distribution network optimized power-saving loss-reducing system takes a secondary substation as a unit, all 10kV outgoing lines, switches and distribution transformers are in a calculation range, and the design values of load nodes calculated by the intelligent power distribution network optimized power-saving loss-reducing system are within 400;
furthermore, the transformer energy-saving management software establishes a dynamic database of each parameter according to the calculation result (the unit loss rate of each electric quantity parameter is calculated), calculates the minimum value of each parameter in the economic operation state of the transformer, and outputs a control or alarm signal after the difference value exceeds a certain range, thereby realizing the real-time control of the transformer loss; the running operation of the transformer can meet the infinite approach to the optimization of economic running parameters, thereby realizing the effects of increasing the yield, saving energy and reducing consumption; the method provides reliable basis for scientific calculation and power supply of power supervisor personnel and higher quality of power grid operation quality.
In the big data era, problems existing in enterprises can be rapidly solved by using big data analysis; how to reduce the loss of the oil field distribution network, the big data plays an important role; the intelligent power distribution network optimization power saving and loss reduction system provides more valuable data information and analysis conclusion after acquiring, storing, managing, analyzing, processing and processing big data;
effective data required by the intelligent power distribution network optimization power saving and loss reduction system are mainly divided into three types:
firstly, the type, capacity, iron loss and copper loss of a main distribution transformer of a distribution network, and the type, length, resistance, reactance and other equipment parameters of a line conductor;
secondly, running states of transformers of the power distribution network and closed state parameters of the breaking switches;
thirdly, operating parameters of the power distribution network such as active electric quantity, reactive electric quantity, current, voltage and the like; the power distribution system has the characteristics of an annular structure and open-loop operation. The power distribution system comprises a large number of normally closed disconnecting switches and a small number of normally open disconnecting switches. Under normal operating conditions, the distribution dispatcher periodically (e.g., seasonally) performs a disconnecting link operation to adjust the network structure (reconfigure the network). Through network reconstruction, on one hand, the load is balanced, the overload is eliminated, and the quality of the power supply voltage is improved; on the other hand, the network loss is reduced, and the economical efficiency of the system is improved. And under the condition of a fault, closing some normally-open disconnecting switches and isolating the fault branch. And opening some normally-closed disconnecting switches simultaneously to make the system maintain an open-loop operation state and transfer all or part of the load of the fault branch to another feeder line or another branch of the same feeder line. Therefore, the network reconfiguration is an important means for improving the safety and the economy of the power distribution system;
the optimization objective function of the network reconstruction of the intelligent power distribution network optimization power saving loss reduction system comprises the following steps:
1. the stability and the reliability of the system are improved, so that the system can carry more loads, and the possibility of load shedding is reduced. A typical objective function is:
Figure GDA0002479916980000181
in the formula NPIs the sum of the number of system load points;
Laviis the annual average load at load point i;
Luithe annual outage time for load point i;
r is the state of all interval switches in the network.
There are generally two ways to improve system reliability: firstly, the reliability performance of each element of a composition system is improved; secondly, the redundancy of the system is increased; however, both methods require increased investment and are not very economical; the reconstruction of the power distribution network can improve the reliability of the system under the condition of not increasing investment; further, there are two types of methods for evaluating the reliability of the power distribution network: one is analytical method, and the other is simulation method; the analytic method is to evaluate and calculate the expected outage events one by one to finally obtain the reliability indexes of the user and the system; the analytic method is simple in principle and accurate in model, and is widely used for reliability evaluation of the radiation type power distribution network; however, when the structure of the power distribution system is complicated, the calculation is complicated. A minimum path method commonly used for reliability evaluation of a power distribution network belongs to an analytical method, simultaneously considers the influence of element faults on the minimum path and element faults on non-minimum paths on load point reliability indexes, can find out weak links of the network, and is a very effective algorithm; the simulation method is used for evaluating the reliability index by simulating the actual condition of the service life process of the element and observing the simulation process for a plurality of times, and is suitable for calculating with a complex system, and even is the only feasible solving method in some specific occasions;
2. the method takes the shortest fault recovery time and the smallest power failure range as an objective function, and the typical objective function is as follows:
Figure GDA0002479916980000191
in the formula yi，ziIs the state of the switch and tie switch; a isiIs a weight coefficient; the power supply of the blackout area is recovered to the maximum extent, meanwhile, the overload of the non-blackout area is not caused, the operation is the simplest and the most convenient, and the problem of the reconstruction of the power distribution network is solved. In the past, Expert System (ES) methods were mostly used. However, since the ES cannot handle special cases that have not been encountered in the knowledge acquisition process, it is difficult to cover all failure modes and operation modes; the workload of knowledge acquisition is large, and some knowledge is not easy to express in a regular form; the optimal solution cannot be guaranteed, etc. This limits the application of the ES;
various algorithms are currently found in the literature. 3 switch indexes containing voltage drop and line parameters are defined, and fault recovery is realized through calculation of the switch indexes. And providing a power distribution network fault recovery reconstruction model comprehensively considering the minimum switching operation times and the minimum network loss. However, the regional power failure recovery problem is a multi-objective, multi-constraint and discrete optimization problem, and the ES and conventional optimization can not be well solved.
3. Load is uniformly distributed, equipment overload is avoided, and the safety and the power supply quality of a power grid are improved: a typical objective function is:
Figure GDA0002479916980000201
Figure GDA0002479916980000202
in the formula, LBi，LBsysLoad balancing indexes of the branch and the system respectively;
Si，Si maxpower flowing through the branch and capacity of the branch, respectively; n isbThe system is a total branch tree.
Due to the rapid change of the load and the lag of the power construction, the load distribution of the power distribution network is greatly unbalanced, thereby bringing great harm, such as increasing the energy loss of the system, influencing the electric energy quality of the system and increasing the risk of overload of the system. There are two main ways to achieve load balancing: firstly, load transfer is carried out among feeder lines of a system level; and secondly, the interphase load exchange of the feeder line level is carried out. A mixed integer nonlinear optimization model is provided and decomposed into two submodels of transformer load balancing and feeder load balancing. However, the decomposition makes the capacity of the feeder line uncertain, and an optimal solution cannot be obtained. A linear integer programming model of network reconstruction is provided for the load balance problem, the objective function and the constraint condition of the problem are accurately represented by a mathematical analysis expression, and the global optimal solution is sought by an analytical method. A new load balancing index is proposed and applied to evaluate the load balancing of the network. A load balancing algorithm for a three-phase unbalanced distribution network is provided. The branch load balancing factors and the overall load balancing factors of the system are used to determine the load level of the system and the capacity of the system.
4. And the active power loss of the system is minimized. A typical objective function is:
minPloss
currently, most of the literature on power distribution network reconfiguration aims at minimizing the real power. But do not
Figure GDA0002479916980000211
The load on each node in an actual power distribution system varies from time to time, and the optimal configuration, which aims at minimizing active power loss, is not likely to be fixed, changes over time, and results in frequent switching operations, which is uneconomical and impractical. Therefore, a practical scheme for minimizing the active power loss is to select a load at a specific time within a specific time period as a calculation load, usually select a peak load, and then propose an optimization scheme of switching operation for minimizing the active power loss in this representative state, so as to complete network reconfiguration. Because an approximate scheme is adopted, the real minimization of the active loss of the system is not realized at the moment of non-peak load, so that a real optimal solution cannot be obtained.
5. The typical objective function for a given period of time (one day, one week or one quarter) with minimal system energy loss is:
in the formula cosTSWIs the operating cost of the switch.
For ease of calculation, a staircase curve is typically used to approximate the actual continuous load curve of the replacement power distribution system while ignoring fluctuations in load over a small period of time (one hour). The essence of the method is to discretize continuous variables, pay attention to the variation trend and ignore small variable quantities, and the purpose is to save energy and simplify calculation. It ensures that the system energy consumption over a given time period is minimal. The method is characterized in that the reduction of the electric energy loss is taken as an objective function of network reconstruction, the former adopts a simulated annealing method to solve, but because a large number of multilevel switch exchanges are needed, the calculated amount is large; the latter adopts genetic algorithm to solve, and the main shortcoming of the method is that different initial gene strings are selected to have different optimization results.
At present, the idea of online monitoring the state of the distribution network switch in the industry is mostly focused on monitoring the internal contact, and whether the internal mechanical contact of the switch is contacted or not is monitored by using a certain technology to judge the opening and closing of the switch. Due to the fact that the types and the models of the switches are various, the switches are required to be modified and different monitoring modules are developed aiming at different switches, and therefore labor is wasted and the cost is increased. Based on the situation, the idea is determined to be changed, and the switch state is judged by using a switch two-end state monitoring method. The principle is that the current-voltage state measuring technology is utilized to monitor the current-voltage change conditions at two ends of the switch to judge the opening and closing of the switch. The method has the advantages that only the state change of the current and the voltage on the two sides of the switch needs to be measured, and the type, the model and the health state of the switch do not need to be concerned. The current and voltage detection unit has the advantages of unified development work, accurate judgment and convenient installation.
The communication type switch inductor is hung near a power line switch and mainly comprises a detection circuit, a trigger circuit, a wireless transmission circuit module, a power circuit and the like. The wireless communication type switch inductors are only one group. Can be directly installed and disassembled in a live way.
Further, a distribution network power flow optimization algorithm: the method for reducing the line loss of the breaking point optimization algorithm platform in the power distribution system is more and more generally concerned and emphasized. The distribution network has the characteristics of closed-loop design, open-loop operation, has a large amount of normally closed section switches and a small amount of normally open contact switches in the distribution lines, and this makes can change distribution network's power supply direction and structure through the state that opens and shuts of transform section switch and contact switch.
Theoretically, the breaking point optimization has an optimal structure, so that the line loss is minimized. The purpose of the power distribution network breakpoint optimization is to seek an optimal power supply mode which minimizes line loss and meet the actual operation requirement. The breaking point optimization can utilize the characteristics of the power distribution network to carry out network optimization, does not need additional hardware investment, reduces the network loss, and can balance the load and improve the voltage quality, thereby being an important means for controlling and operating the power distribution system and also being an important content of the power Distribution Management System (DMS).
Mathematically, the break point optimization belongs to the nonlinear combination optimization problem, and as the system scale increases, the traditional mathematical programming method is adopted to generate the 'combination explosion' problem. At present, methods for solving the breakpoint optimization mainly include a branch exchange algorithm, an optimal flow pattern algorithm, and intelligent algorithms such as SA and GA. The breaking point optimization currently used by people is a novel complex algorithm combining the advantages of a branch exchange algorithm, an optimal flow pattern algorithm and SA and GA algorithms, and the breaking point optimization algorithm has good global optimization capability and relatively small calculation amount. The method is a heuristic search method for expanding the neighborhood, and is also a successful application of artificial intelligence in a combined optimization algorithm. The method adopts effective measures to jump out the local optimal point with higher probability, thereby having strong global optimization performance.
The principle process of our breaking point optimization algorithm: and switching on the interconnection switch with the maximum voltage difference at the two ends to form a ring network in the power distribution network, and switching on a normally closed section switch in the ring network to restore the power distribution network to be radial, thereby balancing the load of each branch and reducing the network loss. These operations are continued until there are no more switches in the network that can reduce the network loss. Many studies have been made on the selection of the interconnection switch and the switch to be opened in the corresponding ring network. The network loss variation caused by switch exchange is approximately calculated by using a method of simplifying a power flow equation and neglecting voltage influence (Ui is approximately equal to 1pu) and a method of heuristic estimation in advance, the maximum network loss variation corresponding to each interconnection switch exchange is calculated at the same time, corresponding switch exchange is executed according to the maximum network loss variation, the calculation efficiency of a branch exchange algorithm is improved to a certain extent, and a simple algorithm of maximum loss reduction switch exchange is determined;
after the device of the intelligent power distribution network optimizing power-saving loss-reducing system is installed, the existing power factor can be improved to 0.75 from 0.37 through the force adjusting rate (power factor), and the efficiency is improved by more than one time. The loss reduction rate of active power is close to 50%, and the loss reduction rate of reactive power is 40%. The power regulation rate saves electricity, 6-10% of the total electric quantity can be saved, and the voltage regulation optimization system aims at improving the voltage qualification rate and reducing the network active loss;
the intelligent power distribution network optimized power-saving loss-reducing system provides an optimal voltage-regulating power-saving scheme by utilizing production and distribution intelligent controllers and related power professional software which are installed on lines mainly according to the model, capacity, active electric quantity, reactive electric quantity, distribution transformer secondary voltage and distribution transformer primary voltage data of all transformers on an oil field distribution line. The voltage is regulated to save electricity, so that 0.8 to 1.44 percent of the total electric quantity can be saved; the production and distribution intelligent controller is a product developed aiming at the loss of a power distribution network, is a power-saving product produced aiming at different operation data of a distribution transformer, can reduce the loss of the power distribution network, and can increase the capacity of the distribution transformer; through years of experiments, the novel product can use the production and distribution intelligent controller as a remote control system, so that the loss of the network can be more scientifically and reasonably reduced by remotely correcting data according to the wirelessly acquired real-time data; enabling entrepreneurs to know the electricity utilization conditions of all production links. The power supply side taps of the transformer in the factory are optimized and adjusted according to the corresponding gear when the total electric charge expenditure is minimum by checking among branch cars, and the power supply side taps of the distribution transformer of the personnel department in the factory are optimized and adjusted to implement the whole-factory power saving and consumption reduction), thereby scientifically and reasonably guiding the power consumption and maximally reducing the power consumption loss of enterprises. Providing a power saving scheme which is practical and is omnibearing for a user; the breaking point optimization system is an important branch of power distribution network reconstruction. In any distribution network, an optimal network structure theoretically exists, and under the optimal structure, the coordination of the operation voltage, the network loss and the load balance of each load point is superior to other possible schemes. When the load changes, the optimal structure also changes, the optimal structure is calculated, and the network operates in an optimal state, which is the main content of the optimization research of the breaking points of the power distribution network. The power distribution network breakpoint optimization is also called power distribution network configuration, or power distribution network feeder configuration and power distribution network feeder reconstruction. The reconstruction of the power distribution network is to select a power supply path of a user by changing the combination state of the section switch and the interconnection switch, so that the aims of reducing the network loss, eliminating the overload, balancing the load and improving the voltage quality are fulfilled. The breakpoint optimization can reduce the total electric quantity by 2-6%; increasing the power factor (power rate) of the transformer reduces the losses of the transformer. The intelligent power saver arranged on the low-voltage side of the distribution transformer is used for dynamically compensating the transformer, automatically adjusting the power rate, effectively improving the power rate of the transformer and reducing the loss of the transformer, and the power-saving technology of the power regulation rate is implemented according to case data statistics of the power regulation rate implementation, so that the loss of the distribution transformer can be reduced by about 50%. About 8-10% of the total charge.
The disclosure above is only one specific embodiment of the present application, but the present application is not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present application.

Claims (9)

1. Intelligent power distribution network optimizes economize on electricity and falls and decreases system, its characterized in that includes: the system comprises a power grid flow analysis subsystem, a power distribution network breakpoint optimization system, a power distribution network reconstruction system, a transformer voltage regulation optimization system, a power regulation and power saving system, a substation main reactance optimization system, a substation reactor optimization system, a substation reactive power optimization system and a central system;
the central system is internally provided with transformer energy-saving management software and an electric charge accounting subsystem;
the power flow analysis subsystem comprises: the system is a most basic subsystem of an intelligent power distribution network optimization power saving and loss reduction system and is used for calculating all operation states of the whole power distribution network; for calculating the distribution of voltage and power;
the power distribution network breaking point optimization system comprises: the system is an important component of the automation of a single power distribution line and an important measure for the safe and economic operation of the whole system;
the power distribution network reconfiguration system comprises: the reconstruction of the power distribution network is to select a power supply path of a user by changing the combination state of all section switches and interconnection switches of each branch line of the full distribution network, so as to achieve the purposes of reducing the network loss, eliminating overload, balancing load and improving the voltage quality;
the voltage regulation optimization system of the transformer aims at improving the voltage qualification rate and reducing the active loss of a network;
the power regulation power saving system can reduce the loss of the transformer by improving the power factor of the transformer; the intelligent production and distribution controller installed on the low-voltage side of the distribution transformer is used for dynamically compensating the transformer and automatically adjusting the force rate, so that over-compensation and under-compensation are avoided, the force rate of the transformer is effectively improved, and the loss of the transformer is reduced;
the power substation main reactance optimization system comprises: according to the characteristics of a power distribution network of an actual oil field enterprise, under a relatively stable load level, the electrical parameter data of a sensor and main transformer equipment of a substation are transmitted to a central system in real time, and the central system changes the operation of a main transformer into multiple modes through load flow calculation to perform load flow calculation, so that a solution of an optimal operation mode is obtained and proposed;
the electric reactor optimization system of the substation: the reactor can absorb redundant line charging power of a power grid, improve the running voltage of the power grid during low-valley load, reduce the phase-entering running depth of power generation and improve the running performance of the power grid;
the reactive power optimization system of the substation: refers to reactive compensation equipment of a transformer substation;
the intelligent production and distribution controller and the transformer energy-saving management software have the functions of optimizing the transformer end, keeping power supply stable and keeping the communication state of the transformer and the transformer energy-saving equipment to be returned.
2. The system according to claim 1, wherein the grid power flow analysis subsystem analyzes the steady state of the power system through power flow calculation of the current system, and can analyze and evaluate the rationality, economy, safety and reliability of the system operation mode through calculation, and the system has the task of determining the operation state of the whole system according to given operation conditions and network structures and providing basic state data and prediction data for energy conservation optimization of other subsystems.
3. The system of claim 2, wherein the reactive compensation equipment of the substation comprises a parallel capacitor compensation device, a series capacitor compensation device and a static compensator.
4. The system of claim 3, wherein the central system monitors the load condition and the grid stability condition in real time, so as to calculate the load flow of the substation through reactive compensation, thereby obtaining an optimal reactive compensation optimization scheme and realizing scientific and reasonable compensation.
5. The system of claim 4, wherein the production distribution intelligent controller is a product developed for the loss of the distribution network, and is a power saving product produced for different distribution transformer operation data, and is capable of reducing the loss of the distribution network and increasing the capacity of the distribution transformer.
6. The system of claim 5, wherein the production distribution intelligent controller is configured to be a remote control system, so as to perform network loss reduction more scientifically and reasonably by performing remote data correction according to the wirelessly collected real-time data.
7. The system according to claim 6, wherein the core functional design requirements of the system are as follows: the numerical values of the total network loss and other parameters of each line of the power distribution network in a multi-state can be calculated; the loss reduction scheme of each power line can be quantitatively provided; thirdly, the optimal combination can be carried out through the disconnection state of the switch, and the percentage of the network loss can be reduced by not less than 3% through disconnection optimization; the intelligent power distribution network optimized power-saving loss-reducing system takes a secondary substation as a unit, all 10kV outgoing lines, switches and distribution transformers are in a calculation range, and the design values of load nodes calculated by the intelligent power distribution network optimized power-saving loss-reducing system are within 400.
8. The system according to claim 7, wherein the effective data required by the system is classified into three categories:
the method comprises the following steps of firstly, the type, the capacity, the iron loss and the copper loss of a main distribution transformer of the power distribution network, and the type, the length, the resistance and the reactance equipment parameters of a line lead;
secondly, running states of transformers of the power distribution network and closed state parameters of the breaking switches;
and thirdly, operating parameters of active electric quantity, reactive electric quantity, current and voltage of the power distribution network.
9. The system according to claim 8, wherein the reconstructed optimization objective function of the system comprises:
the method aims at improving the stability and the reliability of the system, so that the system can carry more loads and reduce the possibility of load shedding, and a typical objective function is as follows:
Figure FDA0002479916970000031
in the formula NPIs the sum of the number of system load points;
Laviis the annual average load at load point i;
Luithe annual outage time for load point i;
r is the state of all interval switches in the network;
secondly, the shortest fault recovery time and the smallest power failure range are taken as an objective function, and a typical objective function is as follows:
Figure FDA0002479916970000041
in the formula yi，ziIs the state of the switch and tie switch; a isiIs a weight coefficient;
the load is uniformly distributed, the equipment overload is avoided, and the safety and the power supply quality of the power grid are improved: a typical objective function is:
Figure FDA0002479916970000042
Figure FDA0002479916970000043
in the formula, LBi，LBsysLoad balancing indexes of the branch and the system respectively;
Si，Si maxpower flowing through the branch and capacity of the branch, respectively; n isbA system main branch tree;
minimizing the active power loss of the system; a typical objective function is:
min Ploss
the system energy loss over a given time period is minimal, and a typical objective function is:
Figure FDA0002479916970000044
in the formula cosTSWIs the operating cost of the switch.
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