IEEE C37.113-1999 is a technical guide for protective relay applications to transmission lines, offering practical direction for power-system engineers working in power, energy, and industrial applications. It addresses how relaying can be applied to transmission line protection, helping support reliable fault detection, selective isolation, and coordinated system operation. As a superseded standard, it remains useful as a reference point for legacy designs, reviews, and technical comparisons where established relay practice matters.

About IEEE C37.113-1999

This standard focuses on the application of protective relays to transmission lines, where correct relay selection and coordination are important to system stability and equipment protection. IEEE C37.113-1999 is commonly used as a guide rather than a prescriptive product specification, so it is especially relevant when evaluating protection schemes, setting practices, and relay functions for line protection. It provides a structured technical basis for understanding how protective relays may be applied in transmission-line environments.

Where is IEEE C37.113-1999 used?

IEEE C37.113-1999 is typically relevant in transmission networks, utility substations, and industrial power systems that include high-voltage overhead or cable lines. It may be used by protection engineers, relay setting teams, and consulting specialists during design, retrofit, or coordination studies. The guide is also useful when reviewing line protection schemes that involve fault clearing, system selectivity, and interface with circuit breakers and related protection equipment.

Importance in practice

In practice, IEEE C37.113-1999 helps support consistent relay application decisions for transmission lines, which can reduce miscoordination and improve fault response. Using a recognized guide can aid compliance reviews, design control, procurement comparisons, and engineering checks for protection studies. For owners and operators of power transmission assets, it provides a technical reference that can support safer operation, more predictable performance, and clearer expectations during testing and commissioning.

• Protective relay application guidance
• Transmission line protection focus
• Utility and industrial power systems
• Legacy reference for superseded practice
• Useful for relay setting and coordination reviews