Summary:The Substation Integrated Automation System combines and optimizes the secondary equipment within the substation, utilizing advanced computer technology, communication technology, and signal processing techniques to achieve comprehensive automation functions, including automatic monitoring, measurement, control, protection of the main equipment and transmission and distribution lines in the entire substation, as well as communication with the upper-level dispatching center.
Keywords:Substation Integrated Automation System; Automatic Monitoring; Protection; Dispatch Communication
Overview
The Qingdao Marine Science Park is situated at the intersection of Jiangshan South Road and planned Zhujiang Road in Huangdao District, Qingdao City, with a planned construction area of approximately 230,000 square meters. The industry is focused on applied marine technology research and development, artificial intelligence, industrial internet, IC design, advanced manufacturing and equipment research. The construction includes scientific research offices and supporting facilities, marine research laboratories, and marine innovation promotion platforms. It is planned to become an integrated platform for Qingdao's applied marine technology resources, a gathering platform for marine technology talents, an incubation and outcome transformation platform for marine technology enterprises, and a cultivation and acceleration platform for marine technology service industries.
The construction encompasses the Marine Technology Industrial Park Production Base (Phase I) project, located north of Shizhai Mountain Road and east of Fenghuang Mountain Road in Qingdao, Shandong Province. It includes Building 1, Building 2, and Building 3, covering a total land area of 53,333.31 square meters and a total floor area of 81,329.49 square meters.
The plant is equipped with one 35kV substation and two regional substations. The 35kV substation includes 35kV switchgear, 35kV transformer armor cases, 10kV switchgear, and 0.4kV switchgear. The regional substations are located in a separate area on the first floor of the equipment building, with 10kV switchgear, transformers, and 0.4kV low-voltage cabinets. This project uses a 35kV single-power supply input, with this substation serving as the main station. The 10kV 1# and 10kV 2# substations derive their power from this substation. The 35kV transformer capacity is 1X10000kVA, the 10kV transformer capacity is 2X800kVA, and there is a backup generator of 1X800kW. The substation houses 4 35kV high-voltage switchboards, 9 10kV medium-voltage switchboards, 1 10000kVA transformer, 2 800kVA transformers, 16 0.4kV low-voltage switchboards, 1 set of 10kV capacitor cabinets, dispatch communication screens, main transformer protection screens, and 1 set of backend equipment, as well as 1 set of 100Ah DC screens, 10kV reactive power compensation totaling 2700kvar, and 0.4kV reactive power compensation totaling 480kvar. The actual power factor after reactive power compensation should reach above 0.95. If not, the compensation capacity must be increased.
Image 1: Qingdao Marine Science and Technology Park on-site photo
System Architecture
The Substation Integrated Automation System refers to a combination of interrelated units that, through the execution of specified functions, achieve a given objective. The Substation Integrated Automation System utilizes advanced computer technology, modern electronics, communication technology, and information processing techniques to recombine and optimize the functions of secondary equipment in substation, and to monitor and measure the operational status of all equipment within the substation.
The system is divided into three layers: the field equipment layer, the network communication layer, and the platform management layer.
On-site equipment layer: Comprises microcomputer protection, intelligent control, multifunctional instruments, and meters, which are used to collect electrical operation parameters, switch states, and electrical junction temperatures within the substation switchboards. Additionally, multiple sets of DC power supplies are configured at both the 35kV substation and the 10kV substation to ensure a favorable operating environment for the on-site equipment.
Network Communication Layer: Includes the ANet-2E8S intelligent gateway. The gateway actively collects data from equipment at the field equipment layer, performs protocol conversion, data storage, and uploads data from the 10kV substation through data collection boxes (integrated with intelligent gateways) via fiber optics to the communication room's comprehensive substation automation monitoring system platform. Simultaneously, the gateway acts as a remote control communication device, collecting field equipment data and uploading it to the dispatching network after encrypting the data through switches.
Platform Management: Substation Integrated Automation Monitoring and Control Platform, Anqing Power Dispatch and Control Center Platform of State Grid Anhui Province.
Figure 2: Network Structure Diagram of the Monitoring System
Solution
This project includes one 35kV substation and three regional substation buildings. The 35kV substation is a two-story independent structure, with the ground floor housing the 35kV switchgear room, 35kV transformer room, and 10kV switchgear room, and the second floor featuring 10kV transformers and a 0.4kV switchgear room, as well as a communication room. The regional substation is a dedicated area on the ground floor of a building, equipped with 10kV switchgear, transformers, and 0.4kV low-voltage cabinets.
The 35kV substation's 35kV switch room single system diagram is shown in Figure 1, featuring 4 switch cabinets: 1 incoming line cabinet, 1 outgoing line cabinet, 1 metering cabinet, and 1 PT cabinet.
Figure 3: 35kV Switchgear Room One-time System Diagram
As shown in Figure 4, the 10kV section of the 35kV substation features a single system diagram with a total of 9 switchgears, including 1 10kV incoming line cabinet, 2 transformer outgoing line cabinets, 2 feeders to the substation, 1 isolation cabinet, 1 PT cabinet, 1 metering cabinet, and 1 spare feeder cabinet.
Figure 4: One-time System Diagram of the 10kV Switchgear Room
Figure 5: One-time System Diagram of the 10kV Substation Transformer Primary Switchgear
Figure 6: Single-line diagram of the 10kV substation's incoming cabinet system, Circuit 2#
Solution Overview
This project involves configuring micro-computer protection devices in 35kV and 10kV distribution systems. Each 35kV and 10kV high-voltage switchgear is equipped with switch status control devices. The system monitors and controls the electrical quantities and the status of electrical equipment (such as circuit breakers). In the event of a fault, the micro-computer protection device collects, monitors, and controls transient electrical quantities, quickly disconnects faulty equipment, and completes post-accident recovery operations.
One multifunctional meter is installed in each 35kV/10kV high-voltage transformer substation switchgear. A metering instrument is fitted at the 35kV substation metering cabinet, where a load collection terminal box is also installed at the 35kV substation. This box collects power information from the metering points, for remote monitoring and electricity data collection.
A DC220V/100AH cabinet-type DC power supply system has been installed in the 35kV substation's secondary control room, while DC220V/50AH distributed DC power supplies are configured in the high-voltage cabinets of various regional substations, ensuring a stable and reliable power supply for critical equipment such as circuit breakers, secondary equipment, and monitoring hosts. A clock synchronization device has been installed to achieve synchronization of the clocks in all microcomputer protection devices, monitoring hosts, protocol conversion devices, and remote control devices within the substation. A comprehensive automation system for the substation has been configured, collecting data from the main transformer temperature patrol instrument, main transformer position transmitter, and DC screen data through protocol conversion devices, and communicating with the decentralized 10kV substation in various regions via fiber optic networking for integrated monitoring and management. A communication screen and a dispatch data network screen have been installed in the secondary control room, along with a set of SDH-type STM-4 optical transmission equipment and a set of PTN access layer optical transmission equipment, all mounted on the optical communication screen. A 48-core 0DF, 16-unit DDF, and 4-port IAD are mounted on the communication wiring screen. At the 110kV Jiangjia substation, two STM-4 optical interface boards and two GE optical modules have been installed on the existing SDH and PTN equipment. One 24-core fiber optic wiring unit cabinet has been installed in the current communication wiring cabinet of Jiangjia substation. Communication between the substation and the dispatching end is achieved through a dedicated point-to-point channel. The dispatch data network screen is equipped with one router, two switches, and two纵向 encryption devices.
Feature Requirements
Microcomputer Protection Requirements
In the integrated automation system of substation, the majority of subsystems are composed of micro-structures, each possessing fault diagnosis capabilities, thereby enhancing the reliability of both primary and secondary equipment in the substation.
The 35kV/10kV step-down transformer circuit utilizes a complete main transformer protection system, featuring a centralized screen assembly. The screen cabinet is located in the electrical monitoring room, equipped with 1 AM5SE-D2 differential protection device, 1 AM5SE-TB high backup protection device, 1 AM5SE-TB low backup protection device, 1 AM5SE-K high side measuring and controlling device, 1 AM5SE-K low side measuring and controlling device, 1 ARTM-8 transformer temperature controller, 1 UP858-19AN position transmitter, and other control equipment such as conversion switches, pressure plates, and circuit breakers.
Differential Protection Device: As the primary protection for internal and external short-circuit faults in the step-down transformer, its function is to monitor the current and voltage on one side of the transformer. If any issues are detected, it promptly issues a warning message. Upon activation, it trips the high and low side circuit breakers of the step-down transformer to prevent transformer faults.
The High-Low Backup Protection Device: Serving as the backup protection for the 35kV side/10kV side and the non-electric protection for transformers, its role is to monitor and protect the entire transformer operation through the collaboration of intelligence and manual operation when both the first two devices fail to function properly. After activation, it trips the high and low side circuit breakers of the step-down transformer, preventing any faults and ensuring the smooth operation of the entire substation.
High/Low Side Measurement Devices: Used for monitoring measurement current and voltage on the 35kV side/10kV side.
Transformer Temperature Controller: Monitors the internal winding temperature of step-down transformers, feeds measured data back to the control system for analysis, and promptly protects the transformer in the background in case of issues.
Tap Changer: Monitors the tap position of the main transformer during operation, used for measuring tap positions on step-down transformers and for on-load voltage regulation.
Local Data Collection
The Substation Integrated Automation System requires the collection of 7 units for group screen protection, 14 units for distributed protection, and 180 instruments, totaling 201 devices. Local equipment is mainly categorized into two types of data: telemetering and telesignaling. Some data are displayed as follows:
- Remote Measurement
- Remote Signal Quantity
Scheduling Upload Requirements
The Huangdao District, named after Huangdao Island, was established in January 1979 when Jiaonan County was reorganized under Qingdao City. That same year, the three people's communes of Huangdao, Xian'an, and Xuejiadao were separated from Jiaonan County to form Qingdao City's Huangdao District. The Qingdao Economic and Technological Development Zone was founded in 1984. In December 1990, Jiaonan County was dissolved and Jiaonan City (a county-level city) was established. In November 1992, Qingdao Bonded Zone was established within the Huangdao District. In 1993, the Qingdao Economic and Technological Development Zone expanded to cover the entire Huangdao District, merging the two district systems. In September 2012, the Huangdao District and the county-level Jiaonan City were dissolved, and the Huangdao District was re-established. The local power grid requires data to be uploaded through two channels: one to the Huangdao District dispatching department and the other through the Huangdao District aggregation center to the Qingdao City platform. Both uploads are done via dual channels, with redundant configurations for the overall scheme to ensure the stability and reliability of the dispatching uploads.
Real-time monitoring
The Acrel-1000 Substation Integrated Automation System features a user-friendly human-machine interface. It can visually display the operation status of distribution lines in the form of a single-phase distribution diagram. It can real-time monitor electrical parameters such as voltage, current, power, and power factor for each circuit. It also dynamically supervises the closing and opening status of circuit breakers, disconnect switches, earthing switches, and related fault and alarm signals.
Primary Transformer Monitoring
Our focus in the 35kV substation is primarily on the main transformer. With an independent interface for analysis, one can view basic transformer information (model, capacity, voltage regulation, temperature), as well as directly check detailed electrical parameters, including three-phase current, voltage, total active power, total reactive power, power factor, and forward active energy. Additionally, a 24-hour power operation curve can be viewed.
Substation monitoring
Each substation transformer independently monitors its interface, allowing direct viewing of detailed electrical parameters and circuit breaker switch states. In the 10kV distribution system, the monitored switch quantities include: circuit breaker opening and closing signals, handcart operation and test position signals, remote/local switching position signals, spring energy storage state signals, grounding switch opening and closing signals, protective tripping signals, and accident warning signals.
Guangzi Brand
The real-time database from the monitoring system is utilized to obtain protection information tables, which are displayed in a multi-column format to show individual equipment spacing protection signals. This system monitors the operational status of various devices, implements limit alarms, and is used by maintenance personnel of the centralized monitoring system for power substations.
Conclusion
The intercommunication between various devices within the substation integrated automation system facilitates data sharing, enabling monitoring and control of substation operations. This plays a significant role in achieving automated grid dispatch and modernized operation and maintenance management, enhancing the safety and reliability of the power grid. Therefore, user substations need to further strengthen their integrated automation system capabilities, improve the skills of operation and maintenance personnel, and ensure the safe and stable operation of the power grid.
Reference
Zhang Xiaochun. Integrated Automation of Substation. Beijing: Higher Education Press, 2006
Liu, S. H. (2016). 10kV Substation Integrated Automation Design. Abstract Edition: Engineering Technology (Architecture), 39.
Hu, Yumin. Discussion on Comprehensive Automation Technology of Substation[J]. Innovation and Technology Guide, 2019: 174-175.
