Kamal Garg

System planning and protection engineering - An overview

System planners are responsible for future planning of system and substation/protection engineers are responsible for the protection system and design. An engineer with an experience of both planning and protection can plan and design an adequate system and protection for the future. This paper aims to provide a comprehensive reference document to the practicing engineers, researchers, and academicians of fast growing developing countries about the system planning and protection engineering techniques and tools practiced in North American Power System, which is one of the largest and most advance power systems.

Capturing generator rotor angle and field quantities - SDG&E experience and approach to using nontraditional generator measurements

Measurements of signals associated with a generator beyond the traditionally measured terminal voltage and current are receiving more attention recently due to their promise of increased insight into the operation of the machine and electrical system during transient conditions. Mechanical measurements such as speed, vibration, shaft strain, pressure, and other physical quantities are already used for turbine protection and monitoring, but the use of mechanical quantities for generator protection has not been investigated in detail. One promising measurement, rotor angle, has historically been of limited use due to a lack of synchronization of the measurement to electrical system events. Present data acquisition technology allows for the highly accurate measurement of machine rotor angle, and when coupled with IEEE C37.118 synchrophasors, such a measurement can be synchronized with other power system measurements to gain a broader understanding of the relationship between the electrical and mechanical systems. In addition, taking time-synchronized measurements of the field voltage and current allows us to gain greater insight into the operation of the machine and has implications beyond traditional generator protection. Such measurements bring greater insight into mechanical transients occurring within the machine during electrical system events and can provide us with a deeper practical understanding of the electromechanical relationship between the generator and the power system. This paper discusses a first-hand experience with the installation and commissioning of a rotor angle measurement system installed on the generators in a 740 MVA combined cycle plant. This installation provides real-time monitoring and recording of the generator rotor angle as well as field excitation quantities. This paper discusses the lessons learned and possible applications using these measurements.

Variable renewable generation and grid operation

With the advancement in wind and solar technology, now large wind-farms and PV systems are being integrated in the power system. This brings new level of challenges for both protection and planning engineers. This paper reviews the renewable power generation technologies available in the current market and challenges in integrating these in the grid. An introduction is provided for the renewable energy available; including wind, solar and ocean etc. This paper also discusses an example of the large renewable project including system planning; establishing the type of generation sources available and discussion of benefits. The paper also discusses the information required for the planning engineer, types of study and challenges before integrating in the existing system. In the end this paper discusses a real life example and sub-synchronous resonance interaction between wind-farm and series capacitor.

Catching falling conductors in midair — detecting and tripping broken distribution circuit conductors at protection speeds

When an overhead electric power distribution circuit conductor breaks—for example, when a car strikes a pole or a splice or clamp fails—the energized conductor falls to ground. The resulting high-impedance ground fault may be difficult or impossible to detect by relays located in the substation. In any case, no ground fault protection relay can operate until well after the time the fault has occurred—after the falling energized conductor has hit the ground and created a hazardous situation. For decades, utilities and equipment manufacturers have worked to develop methods for tripping these hazardous ground faults as quickly as possible. This paper describes a new falling conductor detection scheme that trips the affected circuit section in the narrow time window between the moment of the break and the time the conductor hits the ground. The affected circuit section is de-energized while the conductor is still falling, eliminating the risk of an arcing ground fault or energized circuits on the ground.

Automatic Decoupling System: Preventing the Uncontrolled Shutdown of a Petrochemical Plant

This article is a case study of a dual-primary redundant automatic decoupling system (ADS) for a critical petrochemical process. GPIC selected a new dual-primary redundant ADS to island its system from the external system disturbances. The operation of an as-built ADS was validated against a real-time digital simulation system. Real-time system modeling made it possible to validate the decoupling system operation for various system disturbances and select the set points accordingly. After installation, the new ADS has successfully islanded the GPIC system several times. IE E I n