Summary: Many coal mining companies in our country are facing increasing difficulties in the market environment, as the continuous rise in operational costs further compresses their profit margins, making it challenging for numerous coal mining enterprises to survive and thrive in the complex market scenario. In light of this, this article mainly analyzes the transformation of underground power monitoring systems for coal mining companies.
Keywords: Power Monitoring System; Underground Coal Mines; Renovation
As technology advances and the safety transformation and modernization of coal mining enterprises deepen and develop, the construction of "Five Superior" mines and the creation of digital mines have quietly taken root in the domestic coal industry. To ensure the reliability of mine production scheduling, the addition of mine power protection and monitoring systems is crucial. This facilitates standardized and scientific power scheduling management across the entire mine, which is particularly important under current environmental conditions.
Summary
1.1 The mining area power system cannot be fully monitored.
During the initial design of the power automation monitoring equipment, high-voltage switches at underground and ground sub-stations mostly required the replacement of protective or communication devices to achieve basic electrical signal monitoring and remote control operation capabilities of some high-voltage switches. Many newly constructed and renovated sub-stations within the mining area cannot be monitored due to incompatible communication systems. Additionally, some key ground loads (such as gas extraction stations, vertical shaft fan rooms, and pressure air compressor rooms) were unable to upload data to the power monitoring system due to early financial and technological constraints. These facilities also required 24/7 human staffing for switch operation readiness and routine maintenance inspections.
1.2 Device communication capacity insufficient
The coal mine has successively added power supply for 2 new mining areas and 2 ground sub-stations during its development process. The existing power automation monitoring system's备用communication interfaces are insufficient to support the connection of additional equipment. Additionally, the original monitoring system primarily uses cable communication, with a maximum communication speed of 100 megabits per second. Given the large number of monitored devices, combined with electromagnetic interference from large equipment in the actual operating environment, communication lag frequently occurs.
1.3 The monitored electrical parameters of the monitoring device are limited.
Following a switch short-circuit trip fault underground, dispatch monitoring personnel are unable to quickly ascertain the status of the high-voltage equipment in the underground power distribution room and the fault information reported by the protective system. This hinders technicians in troubleshooting, rapid analysis of the incident, and the self-detection functions of high-voltage equipment.
Composition Analysis of Underground Coal Mine Power Monitoring System
2.1 System Hardware Composition
The system hardware is primarily composed of the following components: power monitoring stations, high-voltage distribution devices, low-voltage combination switches, intelligent protection controllers, surge protectors, explosion-proof switches, industrial control computers, printers, UPS power supplies, and accessories.
The primary functions of an electric power monitoring substation include data collection, display control, and communication transmission. Specifically, the electric power monitoring substation collects comprehensive protection information from the built-in high-voltage feeder switch, displays it on a local touchscreen, and then connects to the coal mine network, uploading the data to the ground. It also receives control signals from industrial control computers to control the operation of the high-voltage feeder switch.
The power monitoring substation is primarily composed of the following components: transformer, power supply, backup battery, display screen, keyboard, communication management unit, optical terminal or optical-electrical conversion module (at least two optical and two electrical).
2.2 Power Supply Monitoring System
The Power Supply Monitoring System is primarily used for monitoring, controlling, managing, and ensuring the safety of coal mine power supply systems and operational equipment. It provides functions such as online parameter monitoring of power supply systems and equipment, remote operation control, real-time accident alarms, data statistical analysis, operational safety protection, electricity consumption metering management, and other monitoring and management capabilities. It offers means for "eight remote controls" including remote measurement, signaling, adjustment, control, surveillance, broadcasting, communication, and testing, as well as accident alarms, protection, localization, and rapid accident resolution. The system provides practical solutions to challenges in power operation, such as power system over-voltage tripping, voltage fluctuation tripping, leakage grounding selection, sudden power outage recovery, and load control. With its high-precision metering and monitoring, professional chart analysis tools, wave recording analysis tools, and intelligent expert systems, it is the latest modern tool for strengthening power supply management, reducing accidents, reducing losses, conserving energy, and improving operational efficiency and management levels. Utilizing system network remote operation control and intelligent programmed control technology, it achieves comprehensive automation and unattended intelligent monitoring and management of coal mine power supply systems and production equipment.
The electric power monitoring system is established on a multi-layer distributed coal mine broadband industrial network platform, which consists of a 1,000 M redundant industrial Ethernet ring, a high-speed dedicated electric power monitoring fieldbus, CAN/RS485 industrial fieldbus, and wireless communication. It is equipped with various electric power monitoring application software and serves as a monitoring, display, protection, control, and collection system with multiple functions. It can be connected to various monitoring devices and environmental monitoring systems with different communication interfaces across different network layers as needed, and is compatible with various interface devices. Additionally, it provides standard data interfaces to achieve seamless connection with the mine automation information platform, supplying power data for the platform, and realizing integrated safety production monitoring and automation/information systems for the entire mine.
The system seamlessly integrates diverse data sources, including power system monitoring, substation environmental monitoring, and IP, IP broadcasting, and video, to achieve a comprehensive power monitoring system with video, voice, and broadcasting interactivity. It establishes a multimedia digital power monitoring management system with broader and more comprehensive monitoring content and scope. This allows management and operation personnel to immerse themselves in an all-encompassing multimedia information environment, enabling more reliable remote management and control.
Underground Coal Mine Power Monitoring System Upgrade
3.1 Power Monitoring System's Main Station Upgrade
Six industrial-grade monitoring servers and four industrial-grade power monitoring workstations have been installed in the power monitoring center of the mine dispatching room. To minimize the possibility of computer virus intrusion during future use and ensure the safe and reliable operation of the monitoring system software, a Linux Chinese version operating system has been adopted. Additionally, six gigabit network switches, six fiber optic network switches, one independent uninterruptible power supply system, and one comprehensive information distribution system have been upgraded and installed.
3.2 Power Monitoring System Substation Optimization
In the upgrade of power monitoring system sub-stations at various sub-stations both underground and on the ground, new explosion-proof gigabit fiber optic switch servers have been installed in the data transmission sub-station devices of each sub-station. For newly constructed sub-stations, protection is directly connected to the fiber optic switch for communication, upgrading the previous megabit communication transmission to gigabit transmission, thus avoiding issues such as transmission lag, signal packet loss, and data delay at the source, and implementing a ring network among all sub-stations. For ensuring the power supply to monitoring sub-stations, a KDW0.3/660A type dual-circuit uninterrupted power supply device has been utilized, ensuring the normal operation of the monitoring system even in the event of power outages throughout the mine.
3.3 Internal Functional Design of the Automation Control System
During the design of an electric power monitoring system, attention should be given to the functional module design to ensure the realization of corresponding functions. 1) The system should have the four remote functions of the underground power system, capable of quickly locating fault nodes, fault types, and recording fault information. 2) The system should enable networking operation between various protective devices and equipment, combining the characteristics of different devices for parameter protection and control, achieving automated control of individual equipment, and providing online monitoring of power equipment. 3) The system should be able to monitor the operation status of various power equipment in real-time and present historical curves and chart data for various types of data information, making this content more intuitive. In terms of data information access control, user sharing should be tiered based on different user types. Fourth, the system should be able to use infrared to comprehensively adjust the parameters of various protective devices, while power supply equipment should operate without interruption, fitting well with the harsh underground environment and ensuring normal operation of all equipment. Fifth, the system interface design should be well-crafted, providing a harmonious human-machine interaction interface, and allowing free switching between sub-systems and other modules, significantly enhancing the system's operational effectiveness.
3.4 Power Monitoring System Unit Node Renovation
Each high-explosive switch is equipped with an intelligent terminal of the DMP-5102B model. This intelligent terminal can locally collect switch position information, electrical signal levels, and temperature data, and also communicates with the comprehensive protection device to package protection action event information for transmission to the monitoring station via optical fiber.
3.5 Remote Control, Telemetry, and Video Linkage Applications
The newly-added intelligent terminal can locally collect electrical data while connecting the control circuits of various circuit breakers to each intelligent terminal. This allows operators to remotely control the circuit breakers of switchgear at various substations from the control room. Additionally, automatic tracking dome cameras by Hikvision have been installed in each substation, which can be remotely aimed at the switchgear to observe the switch's position and operating status during remote operations. They also enable supervision and remote monitoring of the personnel's on-site operations.
Ankorri Power Monitoring System Product Introduction and Selection
4.1 Overview
The Acrel-2000Z Power Monitoring System is a tiered and distributed substation monitoring and management system developed by Ankorui Electric Co., Ltd. in response to the automation and unattended operation requirements of power systems, specifically for voltage levels of 35kV and below. This system, which integrates protection, monitoring, control, and communication functionalities into an open, networked, modular, and configurable system using power automation technology, computer technology, and information transmission technology, is suitable for urban, rural, and user substation networks with voltage levels of 35kV and below. It enables control and management of substation locations, meets the needs for unattended or minimally attended substation operations, and provides a solid guarantee for the safe, stable, and economic operation of substation facilities.
4.2 Application Locations
Office Buildings (Commercial Office, Governmental Office Buildings, etc.)
Commercial Buildings (shopping malls, financial institution buildings, etc.)
Tourism Architecture (hotels, restaurants, entertainment venues, etc.)
Educational, Cultural, Scientific, Research, Medical, Health, and Sports Architecture
Telecommunications Infrastructure (postal, telecommunications, broadcasting, television, data centers, etc.)
Transportation Infrastructure Construction (Airports, Train Stations, Port Buildings, etc.)
Industrial plant construction (oil, chemical, cement, coal, steel, etc.)
New Energy Building (Photovoltaic Power Generation, Wind Power Generation, etc.)
4.3 System Structure
The Acrel-2000Z Power Monitoring System utilizes a hierarchical distributed design, which can be divided into three layers: the station control management layer, the network communication layer, and the field equipment layer. The networking methods can be a standard network structure, an optical fiber star network structure, or an optical fiber ring network structure. The networking approach is determined by considering various factors such as the scale of electricity usage, distribution of electrical equipment, and land area.
Closing Remarks
In summary, the upgrade and transformation of the coal mine power automation monitoring system has achieved unattended operation of the underground substation, reducing personnel while improving efficiency. This has greatly enhanced the automation level of the mine's power supply network, providing a platform for the centralization and safety of the coal mine power supply system.
Reference
Zhou Yao, Research on the Transformation of Underground Coal Mine Power Monitoring and Control System.
Zhao Dalei. Research on the Application of Underground Coal Mine Power Monitoring System[J].
Ankorri Power Monitoring and Protection Product Selection Guide, July 2022.
Ankorri Enterprise Microgrid Design and Application Manual, May 2022.
