Pterra was founded to provide premier consulting services exclusively for the electric power industry. Most of Pterra engagements are per diem, best effort contracts with an agreed upon scope of work, schedule, set of deliverables and budget limit.
Analytical Studies
Power flow analysis
To determine thermal and voltage capabilities on an electrical circuit or grid. This may also include contingency analysis to determine impacts of outages, power factor tests to determine adequacy of voltage support, and transfer limit analysis to measure power injection capacity.
Short circuit analysis
To determine fault levels. This may include breaker-by-breaker analysis for substations, and protection relay setting and coordination.
Positive sequence dynamic simulations
To determine transient and dynamic stability of synchronous systems. The analysis may also be applied to voltage stability and collapse assessment.
Three-phase electromagnetic transient simulations
Also known as EMTP studies applied to simulate transient overvoltages, capacitor switching, recovery of voltage, subsynchronous resonance, among others.
Harmonic analysis
To determine the magnitude of harmonics in an electrical circuit or grid, and design filters.
Flicker analysis
To measure the variation of voltage as it can be tolerated or perceived by electric customers.
Relay coordination
For transmission and distribution circuits to set and adjust relay protection and sensitivity.
Insulation coordination
The necessary and sufficient insulation characteristics of the various network components in order to obtain uniform withstand to normal voltages and to overvoltages that the study system may experience.
Ground overvoltage and grounding bank
Application to determine appropriate size and rating ensuring sufficient protection against high voltages without reducing the sensitivity of relays
Capacitor sizing and switching analysis
To determine the potential overvoltages that a capacitor bank may be exposed to as a function of its planned interconnection, operation and use.Analysis includes measurement of outrush currents.Typical application is to determine type of switching and need for pre-insertion resistors.
Islanding assessment
Is conducted for distribution circuits for which there are planned distributed generation resources. The assessment determines any changes to protection schemes and potential operating conditions that may be a concern from the aspect of islanding.
Transient recovery voltage
Simulations determine if circuit breakers can withstand the high voltage stresses coming from various switching events.