Standards Development

Scope

This Technical Specification (TS) addresses the quantitative assessment of power system stability and security. Its purpose is to establish a standardized approach encompassing the use of terms and de finitions, as well as the objective and general requirements for conducting quantitative assessments. The TS covers the classification of stability and security, classification of quantitative indices, and key considerations for implementing quantitative assessments. This includes selecting appropriate assessment indices, methods for obtaining these indices, model and data requirements, and strategies for improving assessment efficiency. Exemplars of quantitative indices and assessment methods are also provided.

The application of stability and security quantitative assessment serves several purposes. Firstly, it enables the provision of a suitable digital margin to ensure the synchronous operation of the power system and the safety of primary equipment under normal and disturbed conditions. Additionally, it contributes to improving the cost-benefit ratio of power system operation. The TS is applicable to various aspects, such as system planning, operation planning, operation control, stability control syste m design, and stability control decision planning. Through stability and security quantitative assessment, it becomes possible to identify the key factors that contribute to instability and develop methods for enhancing stable operation. These requirements for stability and security can be implemented across relevant power systems. Therefore, conducting stability and security quantitative assessments becomes essential for operating power systems based on risk

Purpose

The purpose of this initiative is to establish standardized practices for the quantitative assessment of power system stability and security, with the aim of achieving multiple objectives. Firstly, it seeks to promote consistency in assessment methodologies, allowing for reliable and comparable results across different systems. Secondly, it aims to facilitate the sharing of relevant engineering experience and best practices in order to enhance the overall benefit derived from these assessments.

By employing stability and security quantitative assessment techniques, power systems can be designed and operated in a manner that prioritizes both security and stability. This entails considering expected load growth and accounting for variations in generation availability during the design phase, ensuring that the system is adequately prepared to handle different ope rating conditions and contingencies. Furthermore, continuous monitoring during operation becomes crucial to verify the presence of sufficient security margins, even if the actual conditions deviate from the initial plans. By adhering to these principles, p ower systems can maintain satisfactory performance over the long term, providing reliable and stable electricity supply.

Justification

Insufficient degree of security and stability within a power system can lead to catastrophic contingencies. In recent years, the world has witnessed several large-scale blackout events resulting from power system stability and security issues. These blackouts have had severe and unforeseen social and financial consequences, rendering the associated risks unacceptable.

Studies conducted by the IEEE Power System Dynamic Performance Committee Task Force on Stability definitions and characterization of dynamic behavior in systems with high penetration of power electronic interfaced technologies indicate that electric power sys tems worldwide are undergoing significant transformations. These transformations have given rise to new stability concerns that require appropriate solutions. The complexity of power system stability and security characteristics has increased due to rapid developments in renewable energy sources and the growing diversification of load types. The integration of converter interfaced generation (CIGs), loads, and transmission devices has further contributed to this complexity. Additionally, limited integrated system planning, market-driven transactions, and increased reliance on stability control systems (such as special protection systems and system protection systems) have exacerbated the situation. Consequently, more stringent assessment requirements are nec essary to ensure that (i) the system is adequately designed with security margins and (ii) sufficient security margins are maintained at all times.

Quantitative assessment serves as a tool to establish a suitable and digital margin for maintaining the synchronous operation of the power system and the safety of primary equipment under normal and disturbed conditions. Furthermore, it improves the cost-benefit ratio of power system operation. The application of quantitative assessment extends to system planni ng, operation planning, operation control, stability control system design, and stability control decision planning. By conducting stability and security quantitative assessments, it becomes possible to identify key factors contributing to instability, det ect weak spots, and develop methods to enhance stable operation. The same stability and security requirements can be implemented in relevant power systems, involving various stakeholders. Moreover, operating power systems based on risk necessitates the requirement of stability and security quantitative assessments.

While issues related to the assessment of power system stability and security are addressed in numerous industrial standards, specialized standards specifically focused on quantitative assessmen t are relatively scarce. Qualitative assessment content is abundant, while detailed content pertaining to quantitative assessment is relatively limited.

This New Work Item Proposal (NP) aligns with the SC 8C roadmap, as prepared by AHG 1 (now AG1), which outlines the action plan and follow-up for standardization in the field of power system stability control. The roadmap includes the development of relevant standards regarding stability control quantitative indicators and evaluation methods, as well as technical specifications for power system security and stability control calculations.

During the SC 8C plenary meeting held via ZOOM on October 19, 2022, a brief introduction was given on the proposal for a new Technical Specification (TS) titled "Guideline s for quantitative assessment of power system stability and security." Subsequently, during the SC 8C WG3 group meeting conducted via ZOOM on April 12, 2023, the proposal for the TS was discussed, covering its background, existing industrial standards on power system stability and security assessment, scope, outline, relevant existing documents, and program of work. Following this meeting, the PowerPoint presentation on the "NWIP TS Guideline for quantitative assessment of power system stability and securit y" and the meeting minutes were circulated to experts of SC 8C WG3