Abstract: This paper focuses on the safety protection of primary electrical equipment in integrated automation systems. An intelligent power distribution monitoring system is designed to achieve online monitoring of equipment operating conditions, local/remote control of various controllable switches, load switching, economic optimization of the power distribution system, and multiple functions including control, interlocking/linkage, communication network connection, and information sharing suitable for various operating modes. The overall system architecture adopts a modular, layered, distributed, and open system structure design, based on the principles of distributed control and centralized monitoring. It is divided by bay, unitized, and distributed to achieve a solution of equipment layering and network layering.
Keywords: primary electrical equipment, intelligent power distribution, monitoring system, distributed control, centralized monitoring
1 Introduction
As high-voltage electrical equipment directly used in the production, transmission, and distribution of electrical energy, the safe and reliable operation of primary electrical equipment directly affects the safe and stable operation of the entire automation system. Therefore, based on the specific requirements for the safety protection of primary electrical equipment in integrated automation systems, we have developed an intelligent power distribution monitoring system. The system's overall architecture adopts a modular, hierarchical, distributed, and open system structure design, adhering to the principle of decentralized control and centralized monitoring. This forms a complete operation, scheduling, and monitoring network, enabling telemetry, remote signaling, remote control, and remote viewing of the entire system. The goal is to achieve unmanned or minimally staffed substation operation and comprehensive monitoring of primary equipment. This intelligent power distribution monitoring system significantly improves production efficiency and reduces accident rates, possessing significant theoretical and practical application value.
2. System Function Introduction
To address the safety protection issues of primary electrical equipment in integrated automation systems, the intelligent power distribution monitoring system is defined to have the following functions:
1. The monitoring host centrally displays the working status, operating parameters, alarm records and other information of each electrical device. The monitoring host sends control operation commands and controls the opening and closing of each controllable switch through the output relay of the automation equipment, which is convenient for on-site operators to monitor.
2. Comprehensive information processing functions: It automatically generates standard format database files from alarm information, operating parameters, operation records, etc., and stores them for long-term use by information systems, enabling data sharing between the automated control system and the production management system.
3. Multiple operating modes coexist. Control modes include: centralized linkage, centralized manual, local linkage, local manual, and emergency stop, making the system operation flexible and reliable. In centralized mode, all equipment is operated by the operator in the central control room via a host computer;
4. By collecting power parameters, faults can be quickly located, facilitating maintenance by staff;
3. System Working Principle
The core technology of an intelligent power distribution monitoring system is to monitor the operating status of electrical equipment, identify abnormal operating status signals, analyze and determine the type, location, and hazard level of abnormal signals, predict the development trend of faults, and make corresponding decisions. As shown in Figure 2-1, the technology of mine belt conveyor status monitoring and accident early warning system mainly includes two aspects: equipment operating status identification and trend prediction. Its specific process is divided into three stages: status detection, analysis and diagnosis, and early warning and management.
Figure 2-1 Three stages of system operation
The designed intelligent power distribution monitoring system can intelligently diagnose and control the system. It can automatically detect and control various faults in the operation of electrical equipment, and provide audible and visual early warning alarms. When electrical equipment experiences abnormal operating conditions, it can automatically detect and control the operation of the electrical equipment and take timely and effective early warning alarm measures. The system design principle block diagram is shown in Figure 2-2.
Figure 2-2 System Design Principle Block Diagram
The system design principle is as follows: When the integrated automation system is running, the intelligent instruments installed on the corresponding electrical equipment can detect their corresponding signal characteristics. The intelligent instruments convert the non-electrical characteristic signals into standard electrical signal characteristics, which are used for on-site display and control, and are also transmitted to the control host. The monitoring host receives the signal, analyzes and judges it, and takes corresponding strategies, such as shutdown, early warning, and alarm control strategies for abnormal signals.
3 System Hardware Design
The overall architecture of the intelligent power distribution monitoring system adopts a modular, hierarchical, distributed, and open system structure design. It follows the principles of decentralized control and centralized monitoring, and is divided by interval, designed in a unitized manner, and processed in a distributed manner to achieve a solution of equipment layering and network layering. The entire system is divided into a field-level control layer and a station-level control layer, as shown in Figure 3-1.
The station-level control layer is located in the centralized control room and typically consists of computers, printers, communication equipment, and uninterruptible power supplies. The computers are connected via a high-speed Ethernet (TCP/IP) network to form a local area network. The hardware uses high-performance, high-reliability industrial PCs, and the system software uses a Microsoft Windows NT preemptive multitasking, multi-threaded operating system to achieve functions such as telemetry, remote signaling, remote control, remote adjustment, alarm display, data storage, statistical reporting, and substation optimized operation control. The integrated monitoring system platform has powerful configuration capabilities and is suitable for the technical requirements of this project. The station-level control layer's monitoring host and other operation workstations all have full access to and control capabilities for various intelligent devices at the field-level control layer. External audible and visual alarm devices are connected to provide alarm functionality, and an external printer is used to print out relevant information.
The automation equipment in the field-level control layer requires highly stable and reliable operation, maintenance-free use, and must also meet the automation design requirements of the project. TPDCMS series intelligent measurement and control instruments are selected as protection and control devices, connected to the monitoring host of the station-level control layer via fieldbus, forming an organically coordinated low-voltage intelligent monitoring system together with the station-level control layer. The TPDCMS series instruments replace traditional power grid parameter detection instruments for data monitoring, mainly including multiple electrical energy parameters such as three-phase voltage, three-phase current, active power, reactive power, apparent power, power factor, frequency, 31st harmonic, and electricity consumption. The instruments automatically perform A/D conversion on the detected data internally, and simultaneously transmit the converted power grid parameters to the fieldbus and host computer through the standard data communication interface configured on the monitor.
The entire system's communication is based on the RS-485 communication interface, using the Modbus communication protocol for data transmission. The TPDCMS3032 is configured with a standard RS-485 communication port, allowing for both centralized panel setups and distributed installations. RS-485 is a two-wire local area network with a communication rate ranging from 300 to 19200 baud. The TPDCMS3032 instrument allows online modification of the communication address and rate, while providing users with an open communication protocol.
Figure 3-1 Structure diagram of intelligent power distribution monitoring system
4 System Software Design
The system software design mainly includes two parts: tool software design and configuration software design. The tool software handles functions such as parameter setting, system configuration, diagnostics, calibration, and testing of switches, controllers, and remote I/O modules in the network system. The configuration software handles functions such as monitoring and early warning information management for each substation and the central station, dynamic graphical display, data report printing, historical data storage, and dynamic trend analysis.
This system combines Visual Basic, Matlab, and SQL database technologies. It is programmed using a dialog box model and implements data acquisition, analysis, and remote control functions through button operations. Matlab is used to calculate the operating parameters of electrical equipment to identify system fault types. A human-machine interface is built using VB to input specific data into the database. The configuration software uses ForceControl, which can display the overall operation screen of the monitoring process, including historical curves, alarm records, parameter settings, status viewing, operation help information, and equipment operation statistics. The system monitoring interface is shown in Figure 4-1, and the interface is required to be simple, user-friendly, and easy to operate.
Figure 4-1 Monitoring interface of intelligent power distribution system
5 Conclusion
This paper introduces an intelligent power distribution monitoring system that improves the automation level of integrated automation systems, reduces worker errors, and enables rapid fault diagnosis and convenient troubleshooting. The system employs visualization technology and object-oriented programming methods, providing a user-friendly human-machine interface. Its overall architecture adopts a modular, layered, distributed, and open system structure design, enabling real-time monitoring of the entire automation system's operation, improving work efficiency, and generating benefits for enterprises. This system significantly enhances the safety and reliability of primary electrical equipment in integrated automation systems, as well as the modern and scientific management level of enterprises, ensuring safe production and yielding substantial social and economic benefits.
References:
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