Abstract This paper introduces the upgrading of the software and hardware of the subway line power system in a city, and analyzes the necessity and feasibility of the power system reform. Discuss specific plans for the transformation of distribution monitoring systems.
Key words metro distribution monitoring power reform
At present, subways are being built on a large scale, and the requirements for low-voltage power distribution systems at stations are also increasing. The service and safety systems of urban subways are also improving. Therefore, on the premise of meeting the increasing function of the subway, it is necessary to reconstruct the old system.
The city's Metro Line 2 was completed and operated for 10 years. It is 20.8 kilometers long and has 12 stations. Each station has a step-down substation, which supplies power for train power, station lighting, and signals. The existing power distribution monitoring system monitors and controls the equipment and disconnectors of each substation at the monitoring station, so that real-time electric parameter data and equipment operation status can be remotely read.
2 system introduction
Station control layer equipment includes master station industrial control computer, slave station industrial control computer, data maintenance computer and data server, and redundant equipment also includes GPS clock, UPS power supply, printer and so on. Network layer devices include network switches, serial servers, and communication front-end machines. The equipment layer includes data acquisition equipment and various types of sensors. Communication channel: The data transmission rate between the OCC communication processor and the remote control interruption is 9600 bps, and the data transmission is half duplex. The interface standard is RS485.
2.1 System Functions:
â— Control function;
â— Screen display function;
â— Information processing function;
â— SCADA equipment self-test function;
â— data processing, display, print function;
â— Password function, etc.
2.2 System Operation Introduction
Since the system was put into operation in 1997, various work conditions have been basically normal. However, due to the rapid development of computer technology and network technology and the limitations of the demand at that time, with the increase in the number of years of operation, the problems of the original monitoring system gradually emerged:
2.3 Status of Power System
In the past 10 years, the system of serviceability, emergency safety, and passenger convenience of urban subways has become more and more complete. Therefore, expansion of power systems, network expansion, management expansion, and requirements standards should all develop accordingly. In recent years, with the large-scale construction of the subway, the construction cost of the station's low-voltage distribution system has gradually increased. For example, the number of escalators increased with the increase in summer air-conditioning refrigeration equipment and winter heating equipment. Electrical fire system embedded and so on.
3 Basic requirements for transformation
1) System Integration Requirements:
The standardization and generalization of software and hardware interfaces are the key to the realization of an open system environment. Therefore, the basic technical requirements for system upgrade and transformation are as follows:
1. Integratability - Establish an open network environment that can be easily connected to systems of different device manufacturers;
2. Interoperability - There is no necessary supporting relationship between the software program and the hardware device, and the best hardware device can be freely selected;
3. Portability - The development of the computing environment will not cause a lot of money and time due to the installation of equipment;
4. Functional Configuration Redundancy - A system with potentially better performance/price ratio access will not disrupt current services.
2) Project organization requirements
1. Because it is necessary to ensure that all loads are operating properly and upgrades of the monitoring system are completed at the same time, the installation and commissioning of the new monitoring system must be safe and efficient, and the principle of remote monitoring of old monitoring systems that are still in operation should not be interrupted. Minimize the switching time of new and old systems as much as possible;
2. The functional testing of the reformed part of the monitoring system shall be scientifically arranged according to on-site allowable conditions, and the quality and quantity shall be completed as required to ensure the correctness of the migration of the monitoring system software and the safety and reliability of the new system equipment after it is put into operation;
3. Perform comprehensive functional commissioning on the retrofitted monitoring system to ensure that the primary equipment can be properly and effectively monitored.
4 My company's specific renovation program
Adopting top-down construction methods, the central station's control floor equipment will be reconstructed first, mainly with the replacement of communication processors, workstation hosts, and analog screens. Then gradually transform the remote terminal in the substation. Specific transformation steps:
1. Install and debug the workstation host, UPS power supply and its peripherals of the new monitoring system. Ensure that the host is operating in an optimized, most efficient state;
2. Increase data server, enhance the storage of large-capacity data, and extend data retention time;
3. Install the serial port server, pre-processor, and analog screen monitoring system to add new devices and power on. Ensure the efficient and stable data transmission;
4. Complete the new background monitoring system database and redundant function settings;
5. Replace all the old instrumentation of the substations with Bai Ruishun's Z series multi-function network power meters. The main functions of the series are: LCD display, all-electric parameter measurement (U, I, P, Q, PF, F, S); four-quadrant energy metering, multiple rate energy statistics; THDu, THDi, 2-31 times the various harmonic components; voltage crest factor, telephone waveform factor, current K coefficient, voltage and current imbalance calculation; Grid voltage and current positive, negative and zero sequence components (including negative sequence current) measurement; 4DI+3DO (DO3 overvoltage, undervoltage, overcurrent, unbalance alarm); RS485 communication interface, Modbus protocol or DL/T645 protocol. Dimensions: 120 Ã— 120mm, opening size: 108 Ã— 108mm. Suitable for high pressure important circuit or low voltage incoming cabinet
6. Test the remote monitoring, telemetry, remote control and telemetry signals of the new monitoring system. After passing the test results, the monitoring signal is sent to the analog screen. After the signal is displayed correctly, the transformation of the upper computer on this substation is completed. According to this step, the monitoring of all substations by the new monitoring system is completed;
7. A substation monitoring data from the original preprocessor RS422 interface parallel access to the new front-end machine;
8. Complete the communication configuration between the new device workstation host and the preprocessor;
9. Exit the OCC equipment of the original monitoring system;
Considering the feasibility of many factors and system implementation steps, Bai Ruishun (Beijing) Electric Co., Ltd.'s power monitoring system was eventually selected.
At this point, the reform of the power monitoring system was discussed.
5.1 When formulating the construction plan, the characteristics of the subway operation should be taken into account. After the daily collection, the maximum working time of 3 hours can be guaranteed. This requires us to meticulously organize and meticulously construct, not only to ensure construction safety and construction quality, but also to affect the normal operation of the next day.
5.2 Before replacing the hardware and software of the old and new systems, observe and record the operation status of the original hardware devices and software programs to avoid introducing the defects of the old system into the debugging and operation of the new system.
6 SignificanceThe urban rail transit industry in China is in the ascendant. The aging of the power monitoring system equipment on the urban rail line put into operation in the 1990s has gradually emerged. In addition, the development of the urban rail power distribution technology is changing with each passing day, and the original monitoring system can no longer meet the new requirements. Equipment expansion requirements. Therefore, exploring an efficient and feasible implementation plan for the transformation of the power monitoring system in the urban rail industry and accumulating practical experience in design and construction have important practical significance.