The substation configuration description file of a smart substation is a hierarchical information model established with the substation configuration description language, which describes the configuration information exchange and interconnection of intelligent devices. The correctness and any changes of the configuration file directly affect the functional accuracy of secondary equipment. With the gradual development of substation expansion and reconstruction projects, the versions of configuration files are also changing frequently.

The management and control of SCD files is of great importance in the commissioning, acceptance, maintenance, overhaul, expansion and reconstruction of smart substations, and there are several urgent problems to be solved:Frequent SCD file upgrades are required during system commissioning, making it difficult for the station control layer and process layer to work in parallel;The existing SCD file version control methods are too extensive to fully describe the details of upgrades;There are a large number of virtual terminals in SCD files, and the configuration of virtual terminals is often prone to missing connections, inaccurate descriptions, incorrect phase configuration and system mismatch. There is no intuitive, fast and effective detection method for the completeness and accuracy of the configuration. Missing or wrong connections of certain channels will seriously affect the safe operation of the entire substation.

At present, the configuration files of smart substations are not standardized, and the configuration process is not intuitive. The change management of smart substation configuration description files is conducted manually, which is not conducive to the design, construction, commissioning and maintenance of smart substations, and system expansion is extremely complicated. It is urgent to carry out research on visual system configuration tools to realize the visualization of virtual secondary circuits for relay protection and provide an effective tool for system maintenance and verification.

To this end, Wuhan Haomai Electric Power has designed and developed a legality detection system for the whole-station configuration SCD file of smart substations. By parsing the .scd whole-station configuration file of smart substations and flexibly saving relevant data in multiple ways, the system conducts semantic checks and virtual terminal legality checks. It can quickly and accurately detect missing IED devices, IEDs with system mismatch, missing virtual terminal channels and misconnected virtual terminal channels in accordance with the self-inspection principle of virtual terminals. This system solves the problem of using inappropriate versions of configuration files during the annual inspection and defect elimination of smart substations, reduces the difficulty of daily maintenance and management of smart substation configuration files for operation personnel, and improves work efficiency.

Functional Modules of the SCD Management and Control Platform

1. SCD Verification

Based on software algorithms for fast parsing of ultra-large XML files and graph theory-based association search, this module intelligently parses the SCD files of smart substations. Combined with the self-inspection principle of virtual terminals for 220kV substations and using the fuzzy matching principle, it not only enables convenient and fast legality checks of virtual terminals in the whole-station configuration SCD file, but also visually displays the network connections between various IEDs in the model file and automatically generates logical connection diagrams of virtual secondary circuits between IEDs.

2. SCD File Comparison

Based on the SCD merging algorithm, this module realizes the comparison function of SCD files before and after modification, and displays the connection status of different virtual terminals in the same bay in the form of lists and graphics.

1. Text Comparison

It parses the verifiable comparison content of CID files through the XML tree structure of the online model and extracts the corresponding XML format, thus realizing the comparison between the online model and the offline model.

2. Visual Comparison

It provides visual display at three levels, the first of which is the IED level, where red indicates differences between the two SCD files.A "+" sign in the line indicates the addition of a virtual terminal, a "-" sign indicates the deletion of a virtual terminal, an exclamation mark "!" indicates a modification, and a "±" sign indicates both addition and deletion of a virtual terminal.

3. File Management

This module conducts version management of SCD files in different regions, facilitating the management and control of SCD files for different substations in various regions and different versions of SCD files for the same substation.

This platform realizes the intelligent parsing of SCD files of smart substations based on fast parsing of ultra-large XML files. It studies the self-inspection principle of virtual terminals and the fuzzy matching principle to check the legality of virtual terminals in the whole-station configuration SCD file, and combines SVG technology to automatically generate logical connection diagrams of virtual secondary circuits between IEDs, thus realizing the legality check of virtual terminals in the whole-station configuration SCD file of smart substations. It solves the problems that the numerous virtual terminal configurations of a single substation require on-site operation and maintenance personnel to check item by item, which is time-consuming and labor-intensive, and the accuracy and comprehensiveness cannot be guaranteed. In addition, the platform can uniformly manage multi-version SCD files in multiple regions, ensuring the correctness and consistency of SCD files imported into devices.