Series-Compensated Line Protection Challenges in the CREZ Region
The Lower Colorado River Authority (LCRA) is protecting a series-compensated line on their transmission grid for the first time as part of the Competitive Renewable Energy Zone (CREZ). This paper discusses experiences in designing, setting, and validating the new protection system.
PG&E 500 kV Protection Standard Design and Development
This paper describes the development of a new Pacific Gas and Electric Company (PG&E) 500 kV transmission line and breaker protection standard, including the motivations for embarking on the project, challenges encountered, and lessons learned during the design effort.
Voltage and Current Inversion Challenges When Protecting Series-Compensated Lines – A Case Study
This paper discusses improving the security and dependability of line current differential protection schemes on series-compensated transmission lines prone to current inversion.
Southern California Edison is protecting a new 500 kV mutually coupled transmission line incorporating both overhead and underground sections. This paper discusses the protection challenges faced with this type of arrangement and describes using real-time digital simulation to evaluate the performance of the protection system.
Considerations and Benefits of Using Five Zones for Distance Protection
This paper discusses application considerations for communications-assisted line protective relays using five distance zones. This discussion includes how modern microprocessor-based relays can benefit the power system when properly applied to pilot protection and backup step-distance schemes.
Considerations When Using Charging Current Compensation in Line Current Differential Applications
Every high-voltage transmission line draws capacitive charging current that a line current differential (87L) relay must compensate for; otherwise, the protection scheme might misoperate. This paper reviews charging current theory, calculations, and compensation methods. It also provides guidelines to help protection engineers determine when charging current compensation is required for an 87L scheme.
PNM Approach to Protecting Overcompensated High-Voltage Lines
This paper discusses a Public Service Company of New Mexico (PNM) project to intersect an existing 345 kV series-compensated line. It also discusses the challenges encountered when protecting overcompensated extra-high-voltage lines and provides a performance comparison of phasor-based and ultra-high-speed protective relays using real-time digital simulation.
CT Saturation on Transformer Energization: Ensuring your Black-Start Generator Stays Online
This paper shows why correct CT selection is important for the reliable operation of generator differential protection and, for instances where the CTs cannot be matched properly, provides insight into different mitigation strategies. The paper examines a case from a user who encountered a generator misoperation during black-start conditions and discusses how the problem was solved using the strategies presented in the paper.
Protection Solutions for your Power System 