Abstract: This paper introduces the design and implementation of a distributed data acquisition and centralized control management power distribution automation system based on Acrel-3000 power monitoring software and power monitoring instruments. The system enables unmanned management by a microcomputer in the power distribution room, eliminating the tedious on-site operation by on-duty personnel, improving power supply quality and management level, and has the advantages of simplicity, practicality, and low investment.
Keywords: Power monitoring software; Power monitoring instruments; Intelligent power distribution system; Application
0 Overview
Currently, many buildings in China still commonly use box-type substations with low-voltage cable junction boxes to achieve decentralized power supply, which brings a lot of inconvenience to the operation and management of the entire system. With the increasing maturity of computer technology and network communication technology, the intelligentization and networking of power distribution system measurement and control functions is an inevitable trend of development. Various problems in the operation of power distribution systems can be fully solved by microcomputers.
The intelligent power distribution system consists of switches equipped with intelligent components with communication capabilities, connected to a computer system network via digital communication, to achieve automated management of the operation of switchgear in distributed low-voltage cable junction boxes. The system can realize functions such as real-time data acquisition, digital communication and program control, and equipment maintenance information management.
This article takes the power management system of Zibo Athletes' Apartment (later renamed Qisheng International Hotel) as an example to briefly introduce the intelligent management of substations.
1 System Analysis
The 22nd Shandong Provincial Games will be held in Zibo on September 19, and the Zibo Athletes' Apartment is designed to serve this purpose.
It is reported that, to ensure the successful hosting of the 11th National Games and the 22nd Shandong Provincial Games, the Zibo Athletes' Apartment, as a sports-supporting project for the two games, entered the feasibility study stage last year. After multiple rounds of review, today, a review panel composed of experts from the Chinese construction industry began reviewing the proposed plans. According to the Zibo City Master Plan and the Zibo New Area Development Plan, the Zibo Athletes' Apartment will be built in the core area of the Zibo New City, in the northeast corner of the planned government affairs district, south of Zhongrun Avenue and west of West 10th Road, with an overall elevation sloping from south to north. The athletes' apartment is expected to have a total land area of approximately 22 hectares, a total building area of 121,660 square meters, with an above-ground building area of 102,922 square meters and an underground building area of 18,738 square meters, and a greening rate of 65%.
In terms of overall layout, the Zibo Athletes' Apartments adopt a garden-style, decentralized combination, balancing independence and connectivity. The architecture primarily follows a modern northern garden style, balancing practicality and innovation. The environment is based on modern northern garden forms, incorporating tradition and unique features. Particularly in energy-saving design, adhering to the principles of "ultra-low energy consumption, natural ventilation, natural lighting, healthy space, renewable energy, and intelligent control," the exterior walls and windows utilize high-efficiency thermal insulation systems, effectively improving the performance of the building envelope. In terms of building materials, lightweight new partition wall materials are used to reduce building weight and save on structural components.
The Zibo Athletes' Apartment Power Monitoring and Energy Management Project started in July 2010. The project aims to achieve centralized management and monitoring of the athletes' apartment's power system and realize a remote intelligent power distribution system.
Before the project commences, the buyer must provide the seller with primary system diagrams, floor plans, and secondary system diagrams for design reference. The seller will design the system according to the buyer's actual needs and the functions of the intelligent components. The main functions include: primary wiring diagram display; remote measurement of electrical parameters and alarms for exceeding electrical parameter limits; event logging and monitoring of system malfunctions; fault alarms and operation logs; energy report query and printing; system load and user access control, etc. The seller may make feasible modifications to the actual detailed functions based on the buyer's usage habits and needs.
The entire system adopts a network-distributed structure. The monitoring host is located in the power center on the basement level in front of Building 2, while the other five power distribution rooms are located on the basement levels of Buildings 1, 2, 3, and 4 (Building 3 has two power distribution rooms, one on the north side and one on the south side). This project realizes intelligent management of the power system in the four buildings of the Zibo Athletes' Apartment. The design scheme involves connecting the five power distribution rooms in the four buildings to the power center on the basement level in front of Building 2 via fiber optic cables and photoelectric converters. Communication cabinets are placed in the five power distribution rooms on-site, and instrument data is transmitted to the power center via the power distribution room through the 485 interface and MODBUS communication protocol via photoelectric converters.
2. System Structure
This system adopts a hierarchical distributed computer network structure, namely the interval layer, communication layer, and station control layer, as shown in the figure below:
Figure 1 Network topology diagram
The main equipment in the mezzanine includes: multi-functional network power meters, digital and analog signal acquisition modules, and intelligent circuit breakers. These devices are installed in electrical cabinets corresponding to the primary equipment. All devices use RS485 communication interfaces and communicate via a field MODBUS bus network to achieve on-site data acquisition.
The middle layer mainly consists of a communication server, whose main function is to centrally collect data from the scattered field acquisition devices and transmit it to the station control layer, thus completing the data interaction between the field layer and the station control layer.
Station control layer: Equipped with high-performance industrial computers, monitors, UPS power supplies, printers, alarm buzzers, and other equipment. The monitoring system is installed on the computer, centrally collecting and displaying the operating status of field equipment, presenting it to users in a human-machine interactive format. Users can also send commands to field equipment via system software to achieve remote control functionality.
All the above network instruments use RS485 interfaces and the MODBUS-RTU communication protocol. RS485 uses shielded wires for transmission, typically requiring only two wires for simple and convenient wiring. The communication interface is half-duplex, meaning both parties can send and receive data, but only one can send or receive data at a time. The maximum data transmission rate is 10Mbps. The RS-485 interface uses a combination of balanced drivers and differential receivers, enhancing noise immunity. Up to 32 devices can be connected on the bus, with a maximum transmission distance of 1.2km.
3. Acrel-3000 Power Monitoring Configuration Software Solution Acrel-3000 power monitoring configuration software is a dedicated software for collecting and controlling on-site production data. Its biggest feature is that it can be used for system integration through flexible and diverse "configuration methods" rather than programming methods. It provides a user-friendly development interface and simple engineering implementation methods. By simply "configuring" its various pre-set software modules, various functions of the monitoring layer can be easily implemented and completed. For example, in distributed network applications, all applications (such as trend curves, alarms, etc.) use the same method to reference remote data as they do to reference local data. The "configuration" method can shorten the system integration time for automation engineers and improve integration efficiency.
After the system was implemented, it realized functions such as displaying the primary system diagram of various electrical equipment, remotely measuring the real-time electrical parameters of each circuit, power reports of important circuits, load power consumption trends of incoming circuits, alarms for opening and closing of important circuits, and user access management. The charts are shown in Figures 2, 3, 4, 5, 6, and 7 respectively.
Figure 2 System diagram
System primary diagram: intuitively displays the three-phase current and operating status of each circuit in the low-voltage system.
Figure 3 Real-time electrical parameters
Real-time electrical parameters: query, print, and export three-phase current, voltage, power, frequency, and energy data for each low-voltage circuit.
Figure 4 Electricity Report
Electricity reports: Energy consumption of important circuits can be queried, calculated, printed, and exported by time period.
Figure 5 Trend Curve
Trend curves: Historical records of current load trend curves for each incoming circuit and important outgoing circuits can be queried.
Figure 6. Circuit breaker opening and closing alarm information
Circuit breaker opening and closing alarm information: remote signaling alarms for opening and closing of important circuits, real-time alarms and historical alarm queries.
Figure 7 User Access Management
User permission management: Users can configure different user permissions, add or remove users, change passwords, etc.
System features: fewer communication cable connections, intuitive screen display, fast data refresh, timely response to the operating status of field equipment, simple system operation, user-friendly interface, various functions can be flexibly changed according to user needs, quick and easy system design, and simple software modification.
4. Conclusion
Configuring network power meters in a power monitoring system offers significant advantages, including ease of implementation and low investment. It allows for convenient and real-time monitoring of the power distribution system's operational status, unified management of on-site electrical equipment, and eliminates the tedious work of on-site recording by personnel. The system manages and analyzes historical operating data and status of various electrical devices, enabling maintenance personnel to clearly understand equipment conditions, develop detailed maintenance plans, reduce manpower, and improve efficiency. Furthermore, based on the established electricity metering system, it is possible to understand and analyze the overall energy consumption of a building, propose energy-saving plans, and implement energy-saving measures to gradually improve electricity efficiency.
References
[1] Ren Zhicheng and Zhou Zhong, eds. Principles and Application Guide of Digital Instruments for Power Measurement, China Electric Power Press, 2007.4
[2] Zhu Liquan. Analysis of Intelligent Management System for Power Distribution System. Intelligent Building Electrical Technology, Vol. 1, No. 4, 2007.
[3] Wang Zhensheng's analysis of "Computer Monitoring System for Substations", Intelligent Building Electrical Technology, Vol. 5, No. 3, 2006
For more detailed information, please contact:
Contact person for Jiangsu Ankerui Electric Manufacturing Co., Ltd.: Xu Yuli, Tel: 13771584106
QQ: 1759867226
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