Rong Si Ci 1
1. Shanghai Acrel Electric Co., Ltd., Shanghai 201801
Abstract: To improve the reliability of the power monitoring system, a fiber optic networking approach was proposed for the power monitoring system of Wuhan Heavy Machine Tool Group, connecting instruments, configuration software, and network equipment. This system assembles the hardware circuitry within the switch cabinet, and uses configuration software to develop and design monitoring software that displays the system configuration and various electrical parameters, enabling data acquisition, monitoring, and management of the power distribution room. The entire system has a high degree of integration and can meet the requirements of Wuhan Heavy Machine Tool Group's power monitoring system for decentralization, networking, and intelligence.
Keywords: Instrumentation; Configuration software; Network equipment; Fiber optic networking
0 Overview
Currently, the development and reliability of the power supply and distribution industry play a crucial role in the development of the national economy. The rapid increase in the number of users of large-scale substations in key projects, landmark buildings, and large public facilities across the country has placed higher demands on the reliability, safety, real-time performance, ease of use, compatibility, and minimizing the impact of faults on power supply and distribution systems.
Acrel-3000 power monitoring system software from Acrel utilizes computers, communication equipment, and metering and protection devices to provide a basic platform for real-time data acquisition, switch status detection, and remote control. This power monitoring system can provide Wuhan Heavy Machine Tool Group with an integrated "monitoring and control" solution, mainly including the real-time historical database AcrSpace, the industrial automation configuration software AcrControl, and the power automation software AcrNetPower.
Wuhan Heavy Machine Tool Group Co., Ltd. (formerly Wuhan Heavy Machine Tool Plant, abbreviated as WHMT) is a large-scale backbone enterprise in China with the largest specifications and most complete range of heavy and super-heavy machine tools. All of its heavy machine tool products are CNC-machined. Most products have reached the international level of the 1990s, and its super-heavy CNC vertical lathes, super-heavy horizontal lathes, and super-heavy CNC gantry milling machines have reached the contemporary international advanced level. It is also the only manufacturer in the world capable of producing a wide variety of super-heavy machine tool products.
Shanghai Acrel Electric Co., Ltd. undertook the design and implementation of the remote automatic meter reading system project for Wuhan Heavy Machine Tool Group. The Acrel-3000 power monitoring system was adopted. The monitoring scope of this system includes the power meters in 13 distribution rooms of 8 units: Weitai Liche Company, CNC Boring Machine Company, CNC Milling Machine Company, Wuhan Shanfu Company, Wuzhong Casting & Forging Company, Large Parts Processing Plant, Small Parts Processing Plant, and the office building.
Based on the actual needs of Wuhan Heavy Machine Tool Group and the functions of intelligent components, the system design was completed. The main functions are: primary wiring diagram interface display; remote measurement of electrical parameters and alarm for exceeding electrical parameter limits; event logging and system operation anomaly monitoring; fault alarm and operation log; power report query and printing; real-time and historical curves of system load and harmonics; user permission management, etc. The seller can make feasible modifications to the actual detailed functions according to the buyer's usage habits and needs.
The entire system adopts a network distributed structure. The monitoring host is located in the 10KV monitoring room. The system adopts an open communication protocol and is connected to the communication server MOXA NPort5430 via fieldbus. The 13 power distribution rooms are connected to the low-voltage power distribution system through fiber optic networking to realize data communication functions.
1. 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:
The main equipment in the bay layer 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, audio equipment, etc. The monitoring system is installed on the computer, centrally collecting and displaying the operating status of on-site equipment, and presenting it to the user in a human-computer interactive format.
All the above network instruments use RS485 interface and MODBUS-RTU communication protocol, and RS485 uses shielded cable for transmission.
2. Main functions of the system
2.1 Data Acquisition and Processing Data acquisition is the foundation of power distribution monitoring. It is primarily accomplished by underlying multi-functional network meters, enabling real-time local display of remote data. The signals to be acquired include: three-phase voltage U, three-phase current I, frequency Hz, power P, power factor COSφ, electricity consumption Ep, and the operating status of remote equipment.
Data processing mainly involves displaying the collected electrical parameters to users in real time and accurately, in order to achieve the automation and intelligence requirements of power distribution monitoring. At the same time, the collected data is stored in a database for users to query.
2.2 The human-machine interface system provides a simple, easy-to-use, and user-friendly interface. It adopts a fully Chinese interface, displays the primary electrical wiring diagram of the low-voltage power distribution system using CAD graphics, shows the status of power distribution system equipment and corresponding real-time operating parameters, dynamically refreshes the screen in real time, displays analog quantities, displays digital quantities, and displays alarm records, etc.
2.3 Fault Alarm and Accident Recall When an operational fault occurs in the power distribution system, an audible alarm will be issued in a timely manner to prompt the user to respond to the faulty circuit. At the same time, the time and location of the event will be automatically recorded so that the user can query and recall the cause of the fault.
2.4 Database Establishment and Query: This mainly involves the timed collection of telemetry and teleindication data, the establishment of a database, and the periodic generation of reports for users to query and print.
2.5 Electricity cost management automatically performs daily, monthly, and yearly electricity statistics, allows for the setting of peak, off-peak, and valley periods, enables time-of-use billing of electricity, and generates daily, monthly, and yearly reports, current curves, etc.
2.6 User access control allows for the addition and removal of software users and the setting of user permissions according to the buyer's requirements. Different permission groups can be set for different user levels to prevent losses to production and daily life due to human error, and to ensure the safe and reliable operation of the power distribution system.
2.7 Instrument Introduction
2.7.1 Install ACR330ELH network power meter at the low-voltage incoming line.
The device has the following functions: three-phase I, U, kW, kVar, kVA, kWh, kVarh, cosφ, Hz measurement; four-quadrant energy metering, multi-rate energy accumulation, THDu, THDi, CF (voltage crest factor), THFF (telephone waveform factor), current K coefficient, positive/negative zero-sequence components of voltage and current, harmonic content of the 2nd to 21st orders; 2DI/2DO, RS485/Modbus, LCD display.
2.7.2 Low-voltage power factor compensation circuit ARC-12/JC type automatic power factor compensation controller.
The device has the following functions: it can control the automatic/manual switching of 6 to 12 groups of capacitors, overvoltage protection, undercurrent lockout, 12DI input, Pt100 temperature detection and control cabinet temperature, etc.
2.7.3 Other circuits ACR220EL network power meters.
Features include: three-phase I, U, kW, kVar, kWh, kVarh, Hz, cosφ measurement, RS485/Modbus. It also has 2DI/2DO, two-channel 4-20mA outputs.
3. Conclusion
Previously, the monitoring systems in each power distribution room operated independently, and the various communication protocols prevented data sharing. This was not in line with the trend towards streamlined electrical staff and centralized system monitoring. Wuhan Heavy Machine Tool Group established a fiber optic network connecting all power distribution rooms, centralized in a single monitoring room. Through software on the centralized monitoring computer, information from the instruments in each power distribution room is read, enabling centralized monitoring of the entire plant's power system. This allows for a comprehensive understanding of the plant's power system status, which is highly beneficial for dispatching and command during power system emergencies.
After scientific design, installation, and commissioning, the entire system achieved its intended functions. The monitoring system controls various instruments; acquires, monitors, and manages data from the power distribution room; and handles alarms. The user-friendly interface and easy operation make the system more intuitive. Furthermore, the system assembles hardware devices in a self-designed universal switchgear, enabling centralized management and facilitating system maintenance and replacement, improving modularity, standardization, and hierarchy, and enabling system expansion. The use of configuration software reduces reliance on manual labor for power equipment status monitoring, lowers labor costs, and improves economic efficiency. It provides a scientific and accurate basis for the production, operation, and management of the power system.
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] Zhou Zhong. Application of Acrel Power Monitoring Configuration Software in Power Distribution Systems
[3] Feng Guohua, Monitoring Configuration Software and Its Application [M]. Beijing: Tsinghua University Press, 2001.
[4] Wu Aiguo. Current status of industrial Ethernet development [J]. Information and Control, 2003, 32(5):458-461.
For more detailed information, please contact:
Contact person for Jiangsu Ankerui Electric Manufacturing Co., Ltd.: Xu Yuli, Tel: 13771584106
QQ: 1759867226
MSN: [email protected]
Telephone: 0510-86179968
Fax: 0510-86179975
Email: [email protected]
Homepage: http://www.jyacrel.cn/
Address: No. 5, Dongmeng Road, Nanzha Town, Jiangyin City, Jiangsu Province
