Abstract: The enterprise power management system is a product that responds to the national call for energy conservation and consumption reduction and refined energy management. It aims to improve the efficiency of terminal power consumption and change the way of power consumption. While satisfying the same power consumption function, it can realize early warning of power consumption and equipment hazards. , Reduce electricity consumption and electricity demand, achieve safe electricity use, save resources and protect the environment, and achieve the goal of "safe electricity use, economical electricity use, orderly electricity use, and smart electricity use". In October 2014, the scientific research project of electric energy management system was launched in the South Station of the fourth water plant (the seventh water plant), and the first batch of 7 monitoring points were established in the power distribution network of the plant area to conduct centralized management of electric energy and electric energy indicators. Through the collection of 7 monitoring points, 24-hour online monitoring and reading of historical data and abnormal fault alarm functions are realized, providing accurate and effective data basis for safe electricity use and normal production, and timely feedback of on-site power index information; Provide reference for implementing the system in water works.
Key words : electric energy management safe use of electricity online real-time quantity control
1 Functions of the power management system
The system includes two parts: software platform and hardware acquisition terminal. The acquisition terminal mainly realizes remote meter reading function and anti-theft function, and real-time measurement of on-site electric energy monitor. The acquisition terminal directly transmits the data back to the server and saves the data to the database. C/S or B/S mode can query data. In a nutshell, it mainly has the following functions: (see Figure 1)
Figure 1 Beijing Water Group Energy Efficiency Management System
1.1 Online real-time monitoring function
(1) Realize the collection function of remote power consumption data (three-phase current, line voltage, phase voltage, electric quantity, power factor, frequency, load rate, active power, reactive power, temperature) of main electric equipment in the area under its jurisdiction.
(2) The parameters of the collection terminal equipment can be set remotely, and the software can automatically freeze the data. The system automatically collects the data every 5 minutes and displays them in the form of curves and graphs.
(3) It has the function of automatic and manual real-time calling and testing.
(4) It has the function of transcribing all and grouping as well as single main equipment.
(5) It has the function of automatic routing to complete the communication of power consumption terminals. No human intervention is required.
1.2 Power quality real-time monitoring function
(1) Carry out automatic inspection on the power quality of the enterprise, display power factor, line voltage deviation, phase voltage deviation, line (phase) voltage unbalance, current unbalance, frequency deviation, voltage (current) phase angle, voltage (current) harmonic Wave content rate, harmonic distortion rate, etc.
(2) Statistics and analysis of the above data; displayed in charts and curves to provide real-time data support for power managers, so as to facilitate the control of enterprise power status and find short boards in power consumption.
1.3 Abnormal alarm function
(1) In order to improve the reliability of power supply, the system automatically collects abnormal events of power indicators (such as frequency, temperature, current exceeding the upper limit, neutral current, harmonics and other index assessments).
(2) Realize big data processing, conduct data analysis, make statistics and submit online fault alarm page, so as to ensure safe and reliable power supply. Safety is the biggest benefit.
(3) Realize the historical (day, month, year) query, statistics and analysis of electric energy data; statistics of electricity and electricity charges. (4)
(4) Decision analysis and report function.
2 Topology structure of power management system
"Power management system" consists of two parts, one is the power management data center, which is the core part of the system; the other is the data acquisition system of the power distribution system. (See Figure 2)
Figure 2 System logic structure diagram
(1) The power management data center is the core of the system, including the data master station system, database system, and data processing and information release system, which is what we usually call a platform. Data Master Station System: The user receives and analyzes the data collected by the sensors of the power distribution system, and finally stores the data in the database; at the same time, it issues instructions to the sensors in the factory to request the required data. Database system: mainly used to store the power index data and the processing results of the data processing system. Data processing system: Process the collected electric energy data into electric energy management information. The system integrates modern electric energy management ideas and electric power technology, which is equivalent to the electric energy ERP of an electric power user. The system includes application server, data analysis model, information display model, intelligent power consumption model, etc. Information publishing system: publish the management information of the water plant to the Web server, and the relevant personnel can obtain the power management information by logging on to the Internet. The system includes Web server, Web application, information security system, etc.
(2) Data acquisition system: collect electric energy data distributed in the distribution network of No. 7 Plant, convert the analog signals of voltage, current and temperature into digital signals, and transmit the electric energy data to the data master station; the main equipment includes electric energy monitor, 485 communication server, 485 communication network, GPRS communication network, etc. The system interconnects various sensors into a network and connects with the master station system, forming the lower part of the above figure.
3 Power management system software
The software functions of "electric energy management system" mainly include main functions such as online (real-time) management of electric energy, power consumption analysis, auxiliary decision-making, orderly power consumption, and equipment operation management. system interface.
The function interface of "Power Management System" is as follows: (See Figure 3)
The home page shows the operating environment of the enterprise's overall distribution network and electric energy parameters to detect whether the distribution network is safe and reliable. Display abnormal information and alarm function to provide reliable forecast data for enterprise users.
Figure 3 Function interface of "Power Management System"
3.1 Electric energy operation diagram
The power movement diagram reflects the movement of power in the current power distribution area and the real-time power indicators of each sampling point, such as: electricity statistics, total load, total power factor, load rate, three-phase current, voltage, zero line current and the The real-time statistics of the power consumption of the load, through this page, you can fully understand the transmission and movement of the purchased electric energy in your own distribution network. The following is the legend: (See Figure 4)
Figure 4 Electric energy operation diagram
3.2 Electricity structure diagram
It reflects the power consumption structure of each power consumption point, which is the proportion of production, office, living and other power consumption at the monitoring point. Through this chart, it can objectively reflect the rationality of the power consumption structure of the monitoring point and guide the rational distribution of power consumption, so that Its power consumption is more reasonable and orderly. The following is the legend: (See Figure 5)
Figure 5 Power structure diagram
3.3 Power real-time operation chart
Through the real-time collection, analysis and statistics of electric energy data, from the aspects of load, power factor, current, and voltage, it reflects the changes and abnormalities of the power index of the power consumption point, the power quality index, and the power consumption of the monitoring point. Provide electricity safety standards and maintenance basis for electric energy management personnel, so as to achieve safe electricity use and prevent problems before they happen. The following is the legend: (See Figure 6)
Figure 6 Real-time power operation chart
4 Work objectives of the electric energy management system of the seventh water plant
The seventh water plant is located in the west of Majiabao, Fengtai District, with a daily water supply capacity of 22,000 cubic meters, ensuring the water supply pressure from the east of Nancheng to the west of Fangzhuang to Yangqiao. Establish an electric energy management system in the No. 7 Water Plant to realize measurable, evaluable, assessable, and sustainable improvement of electric energy management. It speaks through data, and realizes "quantity control" by comparing with its own historical conditions and energy efficiency standards.
5 job content
The power supply system of the seventh water plant is 10KV high-voltage two-way power supply, with a total of 2 sets of SCB9-800/10 transformers, and the reported installed capacity is 850KVA. The electric energy management system has established 7 monitoring points in the seventh water plant, namely 413 (office lighting general), 414-1 (1" water distribution machine power supply), 414-2 (2* water distribution machine power supply), 423-1 (3 "Water distribution machine power supply), 423-2 (heat pump), 401 (incoming line), 402 (incoming line) conduct centralized management of electric energy and electric energy indicators. Collect data on 54 operating parameters (current, voltage, power, temperature, etc.) through a wired network channel, and then transmit the collected data to the server of the fourth water plant through wireless GPRS, and save it in the oracle database to achieve 20 Four-hour online monitoring, reading of historical data and abnormal fault alarm function, adopting B/S structure to realize mobile phone and computer logging into the software system at any place. (See Figure 7)
Figure 7 Power supply system of the seventh water plant
6 System effect analysis
6.1 Improve the level of electricity management
The management system can monitor the electricity load in the factory area. According to the statistical data of the management system platform, the load rate of the transformer is relatively low (load analysis), and the total maximum load rate of the plant area: 54.12% (average load/maximum load).
Figure 8 Analysis of peak, valley and flat power consumption
6.1.1 Analysis of Peak, Valley and Average Power Consumption
From the display of platform operation data, it is known that the peak, flat, and valley power consumption methods of the seventh water plant can be considered or improved in combination with the actual production process and demand, and whether there is room for reasonable use. Beijing's current electricity price policy is: peak electricity price: 1.0044 yuan/kWh, flat electricity price: 0.695 yuan/kWh, valley electricity price: 0.3946 yuan/kWh. The optimization function through the platform preview is as follows: transfer 20% of the peak power load to the valley power, transfer 10% of the flat power load to the valley power, and reduce the electricity fee by 17%. (See Figure 9)
Figure 9 Comparison chart of platform preview optimization
6.1.2 Analysis of Orderly Power Consumption
Through the monitoring of the platform, it can be found that the proportion of power-based systems is accounted for. For example, the average daily power consumption of "413 Lighting" reaches about 100kWh, accounting for about 10% of the total power consumption of 1" transformers.
6.2 Analysis of Electricity Consumption in Safe Production
6.2.1 Power Factor Analysis
According to the platform data analysis, the assessment standard of the power supply company in the factory area is: 0.9, and the actual platform monitoring is: 0.92. The operation is good, and the power supply bureau reduces or exempts the electricity fee by about 300 yuan/month. (Figure 10)
Figure 10 Three-phase power factor recording chart
6.2.2 Current imbalance analysis
According to the analysis of the data platform, it can be known that the maximum value of the current unbalance is reached, and it may cause two major problems of electrical fire and electric energy waste. Put forward treatment suggestions according to the actual situation, and conduct on-site investigation and treatment to prevent problems before they happen, and the safety of water supply is the greatest benefit.
6.2.3 Analysis of Abnormal Report on Power Operation Environment
According to the platform's 24-hour real-time detection of the on-site power consumption environment, abnormal report documents are automatically generated. Provide scientific, effective and timely data for electric energy management personnel, so that they can troubleshoot quickly.
7 Acrel-3000WEB Power Management Solution
7.1 Overview
The user end consumes 80% of the electric energy of the entire grid, and the intelligent power consumption management of the user end is of great significance to the user's reliability, safety, and power saving. Build a smart power service system, comprehensively promote power management solutions for equipment such as user-side smart meters and smart power management terminals, and realize two-way benign interactions between the power grid and users. The research content urgently needed to be solved on the client side mainly includes: advanced meters, smart buildings, smart appliances, value-added services, customer power consumption management systems, demand side management and other topics.
The Acrel-3000WEB power management solution subdivides and counts the power consumption at the user end, and displays the power consumption of each sub-item to managers or decision-makers with intuitive data and charts, so as to find out the high Energy consumption points or unreasonable energy consumption habits can effectively save electricity and provide accurate data support for users to further energy-saving transformation or equipment upgrades.
7.2 Application places
(1) Office buildings (commercial offices, large public buildings, etc.);
(2) Commercial buildings (shopping malls, financial institution buildings, etc.);
(3) Tourist buildings (hotels, entertainment venues, etc.);
(4) Science, education, culture and health buildings (culture, education, scientific research, medical and health, sports buildings, etc.);
(5) Communication buildings (posts and telecommunications, communications, radio, television, data centers, etc.);
(6) Transportation buildings (airports, stations, wharf buildings, etc.).
7.3 System structure
7.4 System functions
7.4.1 Real-time monitoring
The system has a friendly man-machine interface, visually displays the operating status of the distribution line in the form of a distribution diagram, monitors the voltage, current, power, power factor, electric energy and other electrical parameters of each circuit in real time, and dynamically monitors the circuit breakers, Closing and opening states of isolating switch, ground knife, etc., as well as signals related to faults and alarms.
7.4.2 Statistical report of electric energy
The system supports the integrity of the measurement system with rich reports. The system has the function of timing meter reading and summary statistics. Users can freely query the power consumption of each power distribution node in any time period since the system was in normal operation, that is, the statistical analysis report of the power consumption of the incoming line of the node and the power consumption of each branch circuit. This function makes the electricity consumption visible and transparent, and can be analyzed and traced when the electricity consumption error is too large, so as to maintain the correctness of the metering system.
7.4.3 Detailed electrical parameter query
In the primary power distribution diagram, when the mouse moves near each circuit, the mouse pointer changes into a hand shape, and the detailed electrical parameters of the circuit can be viewed by clicking the mouse, including three-phase current, three-phase voltage, three-phase total active power, total Reactive power, total power factor, forward active energy, and 24-hour phase current trend curve and 24-hour voltage trend curve can be viewed.
7.4.4 Running Reports
The system has the storage and management functions of real-time power parameters and historical power parameters. All real-time collected data and sequential event records can be saved to the database. In the query interface, you can customize the parameters that need to be queried, specify the time, or choose to query and update Record data, etc., and display them in a report form. Users can customize and run daily and monthly reports according to their needs, and support exporting Excel format files, and can also export PDF format files according to user requirements.
7.4.5 Transformer operation monitoring
The system conducts online real-time monitoring of the operating status of the main incoming line, main transformer, and important load outgoing line of the power distribution system, and uses curves to display operating trends such as current, transformer operating temperature, active power demand, active power, apparent power, and transformer load rate. Analyze the load rate and loss of the transformer, so that the operation and maintenance personnel can grasp the operation level and power demand in time, and ensure the safety and reliability of power supply.
7.4.6 Real-time alarm
The system has a real-time alarm function, and the system can monitor the remote signal displacement, protection action, accident tripping, voltage, current, power, power factor over-limit and other events such as distribution circuit breaker, isolating switch, grounding knife opening and closing action, etc. Real-time monitoring and alarming according to the event level. When the system alarms, the real-time alarm window will pop up automatically, and a sound or voice reminder will be issued.
7.4.7 Historical event query
The system can store and manage remote signal displacement, protection actions, accident trips, and event records such as voltage, current, power, and power factor exceeding limits, which is convenient for users to trace the history of system events and alarms, query statistics, and analyze accidents.
7.4.8 Power quality monitoring
The system can continuously monitor the power quality within the entire power distribution system. Operation and maintenance personnel can grasp the voltage, current harmonic distortion rate and harmonic content of incoming lines, transformers and important circuits through harmonic analysis bar graphs and reports. , voltage unbalance, etc., take corresponding measures in time to reduce harmonic loss, reduce abnormalities and accidents caused by harmonics (this function needs to be equipped with a power meter with harmonic monitoring function, and can be deleted if not needed.
7.4.9 Remote Operation
The system supports the remote operation of opening and closing of circuit breakers, isolating switches, grounding switches, etc. The system has strict password protection and operation authority management functions. For each remote operation, the system automatically generates an operation record, which includes the operator, operation time, operation type, etc. To realize this function, the circuit breaker itself needs the support of hardware equipment such as electric operating mechanism and protection, measurement and control device with remote control function.
7.4.10 User rights management
In order to ensure the safe and stable operation of the system, the system has set up the user rights management function. Unauthorized operations (such as modification of distribution circuit names, etc.) can be prevented through user rights management. The login names, passwords and operation rights of users at different levels can be defined to provide reliable security for system operation, maintenance and management.
7.4.11 Communication state diagram
The system supports real-time monitoring of the communication status of each device connected to the system, and can completely display the network structure of the entire system; it can diagnose the communication status of the device online, and automatically display the faulty device or component and its fault location on the interface when a network abnormality occurs. In this way, it is convenient for the operation and maintenance personnel to grasp the communication status of each equipment on site in real time, maintain abnormal equipment in time, and ensure the stable operation of the system.
7.4.12 Video surveillance
The video surveillance shows the current real-time picture (live video broadcast). Select a certain substation to view the video information in the substation.
7.4.13 User Reports
The user report page is mainly used to automatically summarize the operation data of the selected substation for one month, and conduct statistical analysis on transformer load, power consumption of distribution circuit, power factor, alarm events, etc.
7.4.14 APP support
The power operation and maintenance mobile phone supports five modules of "monitoring system", "equipment file", "to-do list", "inspection record" and "defect record", and supports primary map, demand, power consumption, video, curve, temperature Humidity, year-on-year, month-on-month, power quality, various event alarm query, equipment file query, pending event processing, inspection record query, etc.
7.5 System hardware configuration list
8 summary
(1) The on-site power consumption data can be collected in real time through the statistics of the power platform. If any power consumption problems such as current imbalance are found, the detection efforts should be strengthened, the maintenance personnel should be notified, and the on-site load situation should be checked and the problem should be solved. Eliminate potential safety hazards.
(2) Targeted control of shortcomings in electricity consumption to save investment on the basis of solving problems.
(3) Under the condition that the power factor of the current plant area is relatively high and can meet the assessment standards of the power supply company, in view of the actual situation that the power factor of the terminal equipment is not high, it is possible to detect whether the existing capacitor compensation is over-compensated or under-compensated, so as to improve Overall standard, to achieve the purpose of reducing or exempting electricity charges. At the same time, local compensation for specific equipment can be considered to improve the service life of the equipment.
(4) According to the actual production time and process of the factory area, it is recommended to make reasonable use of the current electricity price policy. Adopt methods such as "shifting peaks to fill valleys" and "shifting peaks to fill valleys" to reduce production costs of enterprises.
(5) According to the existing monitoring data, if one of the existing two transformers is in operation and the other is in standby, and it is found that the load is not high, one transformer can be used to carry three water distribution machines. Save production costs. To cope with the low pressure of the pipe network in summer and the possible overload operation of water distribution equipment, choosing a reasonable operation mode can ensure the safety of water supply. It can be considered to reduce the transformer capacity in the future transformation. With the long-term operation of the system, in view of the abnormal alarms provided by the system and related problems detected, it provides optimized power consumption structure or production process, provides relevant system guarantees, and predicts the changing trend of power consumption environment to guide production and operation.