Summary:This article starts with the current application status of digital substation technology in power enterprises' transformation stations, analyzes the main advantages of digital substation technology and the path for digital upgrading of power enterprises' transformation stations. It also discusses the development direction of digital substation technology in power enterprises, aiming to provide theoretical support for the digital transformation of power enterprises' transformation stations.
Keywords:Digital Substation, Power Utility, Substation Application
- Introduction
In the production process of power enterprises, a large amount of electrical equipment is required, and the application of this equipment is crucial for the safety and stable operation of power enterprises. Moreover, the power supply and dispatching of power enterprises' power grids have high requirements in conjunction with electrical equipment. In the past, the level of automation in power enterprise substations was not high, and there were significant shortcomings in power protection facilities. In addition, there were issues with poor coordination between different electrical equipment, greatly impacting the production efficiency of power enterprises. With the advancement and improvement of overall technology in China's power system, leveraging computer-assisted and automated control equipment, power enterprise substation can achieve digital construction of electricity, laying a solid foundation for stable and effective power supply in power enterprise production. This article provides a brief analysis of the application of digital substation technology in power enterprise substations.
Current Application Status of Digital Substation Technology in Power Enterprise Substations
1.1 Current Status of Power Enterprise Substation Development
In the current production environment of power companies, most, especially small and medium-sized power companies, are still at the traditional substation equipment stage. Their main components consist of primary and secondary equipment. The primary equipment primarily includes transformer units, circuit breakers, and isolation devices. The interconnection and coordination between different equipment in power company substations are mainly achieved through cables, linking control equipment with primary equipment. This method of signal transmission has a significant impact on power control, resulting in longer equipment response times and limited functionality expansion, as well as higher overall operation and maintenance costs. With the continuous development of science and technology, power equipment has also undergone updates and replacements. The emergence and application of transformer equipment, as well as the use of intelligent circuit breakers, have provided a foundation for the development of digital substation technology. Voltage control between substations can be automated through intelligent equipment, providing strong support for the intelligent and automated transformation of power company substations. The secondary equipment is mainly composed of measuring equipment and protective devices. Upon the completion of the digital construction of power company substation, it can integrate power control and protection, enabling electrical signal control of power equipment, enhancing equipment response speed and safety.
Key Technical Points of Digital Substation Technology
From the perspective of the application of digital substation technology in power enterprises' transformer stations, on one hand, digital substation technology significantly enhances the power grid management capabilities of power enterprises and promotes the improvement of distribution efficiency. The application of digital technology in power enterprise transformer stations has a notable effect on the overall efficiency of transformer stations. Therefore, during the transformation and upgrading of power enterprise transformer stations, attention should be paid to the comprehensive application of digital software and hardware systems, combined with the actual production and power consumption needs of power enterprises and the actual grid settings, ensuring detailed records of the transformation process. This enhances the number of digital intelligent devices in use, ensuring that the power grid of power enterprises always operates within a safe and reliable range. On the other hand, in terms of control methods for power enterprise transformer stations, compared to the traditional manual adjustment of power lines, digital substation technology, under computer control, can utilize various intelligent terminal devices to automate line adjustments, reducing the reliance of power enterprise transformer stations on manual labor and greatly improving the efficiency of transformer operations.
1.3 Digital Development Foundation for Power Enterprises Substation
In the domestic power industry, substation transformation towards digitalization is advancing, with the rapid popularization of intelligent grid transformation equipment. Among the digital substation technologies used by power companies, hybrid optical current transformers and pass combination switchgear are particularly representative. The quantity and quality of intelligent equipment installed in power company substations are crucial for the success of digital transformation. Intelligent equipment in power company substations requires relevant technical standards and is interconnected within a unified technical framework. The IEC61850 communication protocol provides effective technical standards for the construction of digital substations, holding significant guiding value for their digitalization. The IEC61850 communication protocol supporting the digital transformation of power company substations is mainly composed of the substation layer, bay layer, and process layer (Figure 1). The application of digital substation technology in power company substations can effectively reduce the impact of human factors on power production and supply, alleviate the workload of power staff, strengthen the power company's control over power resources, maintain high-level power dispatching, and improve power utilization.
2. Key Advantages of Digital Substation Technology
Compared to digital substation technology, traditional power substation applications for power companies have significant technical deficiencies, particularly in terms of electrical safety and power supply stability. When it comes to major adjustments to electrical equipment, the flexibility of the power network in making adjustments is notably lacking, failing to meet the power demands of mining equipment for power companies, resulting in lower power supply efficiency. During the digital transformation of power company substation, distinct characteristics emerge. The replacement of electromagnetic protection devices with electronic protection devices, transitioning from simple computerized remote protection systems to integrated automatic protection. With continuous equipment upgrades, power company substation gradually achieves digitalization, specifically through the intelligent enhancement of primary equipment, the networking of secondary equipment, and both through computer control technology, effectively controlling power lines and enhancing the automation level of the power network. The practical advantages of digital transformation in power company substation are mainly reflected in:
- The electronic current transformer terminal device boasts excellent performance, with good installation and maintenance properties, as well as superior insulation. The CT dynamic range is wider compared to traditional transformers, exhibits no magnetic saturation, and offers a significant improvement in performance compared to conventional transformers.
- Function switches widely used in digital substation applications enable the digital control of power supply network signals for power enterprises, significantly enhancing the efficiency and speed of signal transmission. This effectively reduces the cable usage between primary equipment and other electrical devices, thereby lowering the maintenance and construction costs of the power grid.
- In traditional power enterprise substation construction, various types of electrical equipment with different specifications are commonly used, leading to low compatibility between different manufacturers and models. This results in poor harmony between systems, causing equipment connection failures during actual use. Not only does this reduce the efficiency of power transmission, but it can also trigger faults in the power supply system, halting production for power enterprises. The application of digital substation equipment, utilizing the standardized IEC61850 communication protocol, enables effective equipment integration over a broader range and offers high equipment scalability, allowing for efficient upgrades as needed.
- In the application of IEC61850 communication protocols, through the communication functions of digital devices, the interlocking logic of substation operations can be achieved without reliance on switching equipment, significantly enhancing the overall reliability of substation equipment over traditional power enterprise substations.
3. Digital Transformation Path for Power Utility Substations
Currently, there are generally three approaches to the digitalization of power enterprises' substation transformation. The first is to adopt the IEC61850 communication protocol for the digital transformation of traditional power enterprise substations, constructing transitional substations with preliminary grid intelligence. The second is to build practical digital substations for power enterprises based on the IEC61850 communication protocol. The third is to construct fully digitalized substations from the outset, utilizing intelligent equipment. Due to the relatively low level of technical exploration and accumulation in primary equipment of the power grid in our country, the latter approach can be adopted in the construction of new power enterprise substations, significantly enhancing the digitalization level. Moreover, traditional substation equipment can be digitally upgraded to save costs in constructing a digitalized power grid. By utilizing the IEC61850 communication protocol for equipment integration, the digital transformation of power enterprise substations can be achieved. This transitional digital substation primarily connects through the IEC61850 communication protocol, allowing intelligent power equipment that supports the protocol to be integrated into the digital substation network, enabling intelligent control.
In this system, digital power equipment boasts good system compatibility, all supporting the IEC61850 communication protocol. It can upgrade and enhance the substation system through interface functions. Software upgrades can effectively reduce maintenance costs for power enterprises' substations while making the substation system more adaptable to the production needs of power companies. In the secondary circuits of power enterprise substations, relay devices can be upgraded through programming, and all equipment can be linked to the control system via fiber optics, optimizing the control system circuit settings. Power equipment in the transition phase must support the IEC61850 communication protocol, with device information transmitted via industrial Ethernet. If only equipment supporting the IEC61850 communication protocol is available, it can be directly connected via industrial Ethernet. If intelligent devices cannot effectively connect to the IEC61850 communication protocol, they must be connected through relevant conversion devices, and then data connections are made via industrial Ethernet.
4. The Development Direction of Digital Substation Technology in Power Enterprises
4.1 Automated Control System
In today's power industry production environment, an increasing number of power companies recognize the role of digital substations in enhancing energy efficiency and ensuring power supply safety. They are now transforming traditional power substation into digital ones, integrating a wealth of digital equipment to achieve intelligent transformation of the power supply system, thereby improving production efficiency. Compared to traditional power substation, digital substations can effectively prevent and manage power substation faults, and after a fault occurs, they can accurately detect the fault location through intelligent devices, significantly reducing fault handling time and enhancing equipment maintainability. The automation of power substation primarily includes分流交换自动化, data recording, power work data, and information stratification. Maintenance staff of power company digital substations can monitor the operation status of the substation through automatic monitoring systems, achieving automated system operations.
4.2 System Integration
A key feature of digital substation is the highly integrated power system, which, supported by various types of intelligent terminals, allows for effective system integration through common communication protocols. Compared to traditional power enterprise substation systems, the transformer systems are more integrated in nature. Overall, digital substation mainly includes the following aspects. Firstly, the effective integration of intelligent power equipment using the IEC61850 communication protocol is a crucial foundation for constructing digital substation systems in power enterprises. Currently, the majority of power enterprises' digital transformer systems are built based on the IEC61850 communication protocol. In terms of practical application, the compatibility of the communication protocol is good, enabling effective integration of transformer intelligent equipment resources and achieving intelligent control of the substation. Therefore, the application of the IEC61850 communication protocol in the construction of future power enterprise digital substation systems will be even more widespread. Secondly, the hierarchical control of digital substation. When applying digital systems, power enterprises need to centrally manage and control the hierarchical control of substation systems. Different from traditional transformer management models, the automatic control systems of digital transformer systems will operate through hierarchical control to effectively operate various power facilities based on transformer demands. This requires digital transformer equipment to have a certain level of intelligence, enabling information exchange within the control system in automatic mode and achieving seamless connection with control equipment, thereby improving the response speed of power enterprise substation systems.
4.3 Network Technology
In the technological composition of power enterprises' digital substation, network technology is the core that ensures the construction and operation of the digital substation. Due to the large scale of production, power enterprises utilize local area networks to link various positions and work content in both management and production. Similarly, in substation operations, local area networks transmit information about electrical equipment to the digital substation system, where computers analyze and issue different command signals, enabling more effective control over power transmission. The use of fiber optics for information transmission is fast and has lower construction costs, making it more suitable for modern power enterprise production compared to traditional cable transmission.
5. AcrelCloud-1000 Substation Operation and Maintenance Cloud Platform
5.1 Overview
The cloud-based management platform, developed based on technologies such as the Internet+, big data, and mobile communications, meets the needs of users or operation and maintenance companies to monitor the operating status and parameters of numerous transformer substation circuits, indoor environmental temperature and humidity, cable and busbar operating temperatures, as well as on-site equipment or environmental video scenes. It achieves centralized storage and unified management of data, facilitating usage. It supports authorized users to access and receive alerts through various terminals such as computers, smartphones, and tablets, and completes daily and regular inspection and dispatching management of equipment.
5.2 Application Venue
New and expanded power distribution and maintenance systems for the telecommunications, finance, transportation, energy, healthcare, culture and sports, education and scientific research, agriculture and water conservancy, commercial services, and public utilities industries.
5.3 System Structure
The system is divided into four layers: the perception layer, transmission layer, application layer, and presentation layer.
The perception layer includes multifunctional meters, temperature and humidity monitoring devices, cameras, and switch quantity acquisition devices installed at the substation. Apart from the cameras, the other equipment is connected to the on-site intelligent gateway's RS485 port via the RS485 bus.
The Transmission Layer includes devices such as field intelligent gateways and switches. The intelligent gateway actively collects data from devices at the field equipment layer, performs protocol conversion, data storage, and uploads the data to the server port via the switch. In the event of a network failure, data can be stored locally and then continued to be uploaded from the point of interruption when the network is restored, ensuring that no data is lost on the server side.
Application Layer: Comprises the application server and database server, which can be configured together if there are less than 30 substations. Servers must have a static IP address to receive data actively transmitted from each smart gateway.
The Display Layer: Users can access platform information through multiple terminals such as smartphones, tablets, and computers.
5.4 System Features
5.4.1 Monthly Energy Consumption Report
The Energy Consumption Monthly Report supports users in querying the electricity consumption of their managed stations by total electricity usage, substation name, and substation number, etc.
5.4.2 Site Monitoring
Site monitoring includes an overview, operational status, daily event log, hourly electricity consumption curve for the day, and a summary of electricity usage.
Transformer Status now supports users to query all or specific station transformers' power, load rate, and other operating status data. It also allows ranking in ascending or descending order based on load rate and power.
Operations showcases the current location and total information of transformer substations on the map for user management.
5.4.5 Power Distribution Diagram
The distribution diagram showcases the power distribution information of the selected substation. It illustrates the switch status and operating conditions, such as current, of each circuit, and supports detailed queries of operating parameters, including voltage, current, and power.
5.4.6 Video Surveillance
Video surveillance displays the live feed (video streaming). Select a specific substation transformer, and you can view the video information within it.
5.4.7 Electric Power Operation Report
The power operation report shows the real-time and average values of the operation parameters and electricity meter readings for each loop of the selected equipment at the selected station, with statistics performed on the collection intervals.
Analyze all alarm information on the platform.
The task management page allows for the posting of inspection or defect elimination tasks, viewing the status and completion of these tasks, and clicking to view specific inspection details.
The User Report Page is primarily designed to automatically compile one month's worth of operational data for selected transformer substations. It provides statistical analysis of transformer loads, power consumption of distribution circuits, power factor, and alarm events. It also lists various defects found during inspections within this period and the corresponding corrective actions.
5.4.11 APP Monitoring
3.12APP supports the "Monitoring System," "Equipment Records," "To-Do List," "Inspection Records," "Defect Records," "Document Management," and "User Reports" modules for power operation and maintenance on mobile devices. It offers functionalities such as one-image display, demand, electricity consumption, video, curves, temperature and humidity, year-on-year and month-on-month comparisons, power quality, and various event alarm inquiries. It also includes equipment records search, to-do event management, inspection record inquiries, user reports, and document management.
6. Closing Remarks
In summary, as power companies undergo modernization and transformation, it is essential to update production equipment and organizational methods. Prioritizing the digitalization of substation construction is the first step in modernizing production equipment. The application of digital technology in power company substations is a crucial aspect of the modernization transformation of China's power industry. Effective digital substation construction aids in enhancing production efficiency, improving grid power supply stability, and ensuring smooth operations for power companies. Substations serve as energy hubs for power production. With the continuous advancement of China's power technology, the digital transformation of power company substations will be a major trend in future power industry reforms. While undergoing digital transformation, power companies must consider their power consumption needs and transformation models, selecting appropriate production transformation methods based on the maturity of technology. By installing intelligent power equipment, the gradual digital transformation of substation facilities can be achieved, and the transformation of power company substations can be safely and steadily advanced.
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