Transient Testing of Transmission Relays

Ferro-resonance Study

Protection system transient study of a 500 kV transmission corridor between two major US utilities.  The objective of the study was to create transient files to test the relay settings and performance through factory and field tests.  COMTRADE files were produced for various fault locations, fault types, incidence angles and fault resistances using a thoroughly validated system model.  The study generated over 30,000 transient scenarios.  We also provided the real-time playback (RTP) test equipment and facilitated in the factory tests.

Ferro Resonance for Instrument Transformers: Third party review of a study to investigate over voltage operation of auxiliary voltage transformers during switching transients at Exelon nuclear switchyards. This study involved a detailed parametric study of the protection circuit including the CCVT. The review provided several recommendations that helped to justify a detailed laboratory test by the vendor to provide a satisfactory modification of the protection circuit to avoid ferro-resonance.

Fast Bus Transfer in Nuclear Plants

Photo Voltaic Cell Systems

Fast bus transfer study of the Indian Point III nuclear power plant using PSCAD/EMTDC. PSCAD was already validated for nuclear applications in a similar project for the Indian Point II nuclear station.  The plant model consisted of many induction motors, bus-work, 230kV and 138kV feeders, transformers and sequencing logic.

Protection system study of a distribution system with Photo-Voltaic Cells using PSCAD/EMTDC. The study focused on protection system performance during faults and various system conditions.

Fuel Cell Systems

Electric Ship Systems

Protection system study of a distribution system with Fuel Cells using PSCAD/EMTDC. The study focused on protection systems during faults and control performance under islanded operation.

Detailed modeling of an electric ship (Navy) power system including propulsion motors, power generators, variable speed drives and frequency converters.

Bus Transfer Study

Transformer Inrush Study

Fast bus transfer study of the Indian Point II nuclear power plant using PSCAD/EMTDC. This involved verification of PSCAD models against other simulators and field tests to validate for nuclear applications. The plant model consisted of many induction motors, bus-work, 230kV and 138kV feeders, transformers and sequencing logic.  Click Here for a journal article on the study.

Study of emergency transfer to a diesel generator at the Limerick nuclear power plant using PSCAD/EMTDC. This project studied the transformer inrush transients and relay performance. 

Large System Modeling

Wind Farm Systems

Modeling of the WECC transmission system including the HVDC System in PSCAD. This was a huge modeling effort that included 500 kV systems from Southern California up to British Columbia.

Transient performance study of a distribution system with wind generation using PSCAD/EMTDC. The model was designed to study the performance of a doubly fed induction generator wind system under islanded conditions.

HVDC Controls Modeling

Capacitor Switching Studies

Modeling of Cheju-Haenam HVDC System in PSCAD/EMTDC and RTDS. This was an extensive project consisting of modeling the HVDC controls at the circuit board level and modeling the adjacent AC system. This project took about four person-years to complete over a one year period. This work was later used by the client to model their HVDC system on a RTDS real-time simulator.

The installation of shunt capacitor banks at transmission line substations raises various concerns regarding the protection of the banks themselves, as well as the protection of other substation equipment. These concerns are mainly due to the high inrush/outrush currents and overvoltages that are generated during capacitor switching and close-in fault clearing. Transient concerns include phenomena such as ferro-resonance, temporary overvoltages (TOV), transient recovery voltages (TRV), high frequency system resonances and voltage magnification at nearby locations.  The first objective of this study is to optimally determine the ratings of the inrush and outrush reactors and the surge arrestors. The second objective is to investigate any unfavorable system interactions due to the presence of these capacitors on the system as well as their switching operations.  Nayak Corporation has performed several capacitor switching transient studies using PSCAD to address these issues.