N. Bhatt et al.
The SRN 3.0 generates a restoration plan under the users’ guidance iteratively. The step by step evolution of
the restoration plan can be displayed in substation one-line diagrams and transmission overview diagrams. As
components are energized, they are colorized so that the extent of the electrical islands is apparent to the user.
The SRN 3.0 determines a sequence of efficient circuit breaker operations to energize various system compo-
nents. It finds a feasible sequence, which has shortest estimated time duration to crank non-black start (NBS)
generating units and to pick up loads for the purpose of controlling voltage and frequency and meeting unit
minimum limits.
Once SRN 3.0 module is integrated with an operator training simulator, its usefulness is enhanced signifi-
cantly. The OTS power system map, the underlying power system model and the station one-line displays can be
used to show the impact of the breaker operations produced by SRN 3.0. The OTS AGC function can be used to
maintain frequency in islands as load is added to the system. The AGC function can also be used to ensure that
the generators observe their minimum and maximum operating limits, and ramp rates.
2.2. Integration of SRN 3.0 Module into an OTS
SRN 3.0 has been developed for integration with Operator Training Simulators of multiple vendors. SRN 3.0
can be integrated with an existing operator training simulator using the API software as the reference. Once the
integration is complete, SRN 3.0 can establish a system restoration plan following a complete or partial outage.
The plan can then be displayed on OTS maps and one-line diagrams. Users can control the restoration process
interactively by selecting the sequence of generating units and loads that are organized.
Commercial Operator Training Simulators typically consist of two subsystems:
• A Power System Model that simulates the long term dynamics of the power system as a base.
• A Control Center Model that simulates the control center software and hardware including SCADA, AGC
and possibly other network applications such as State Estimator and Contingency Analysis. A Control Cen-
ter Model may be an exact replica of an existing Control Center or it may be software that emulates the op-
eration of a variety of control centers.
The instructor interacts with the Power System Model and can create all sorts of events to simulate normal as
well as emergency events such as hurricanes, tornados, ice storms, cyber-attacks, physical attacks etc. The in-
structor also plays the roles of neighboring system operators, Reliability Coordinators and field crews.
The system operator works with the Control Center Model, and monitors and controls the simulated power
system through SCADA, AGC and network application displays.
2.3. SRN 3.0 Functionality
SRN 3.0 has been designed and developed to provide system operators and engineers with a new tool that can
significantly improve the quality, efficiency and robustness of system restoration analyses. SRN 3.0 is scalable
to handle practical large systems and operational models that include node-breaker details.
In a similar way to how automobile GPS navigation software provides someone that is in unfamiliar territory
or complicated road conditions with very helpful step by step directions, the EPRI SRN 3.0 can provide an en-
gineer or system operator that is unfamiliar with a power system or a system condition with prioritized feasible
options and specific step by step directions for implementing the selected options.
SRN 3.0 has been designed to help a student or an engineer to emulate the thought processes and control ac-
tions of an expert system operator.
Further, in a similar way to how automobile software provides real time updates of the driver’s location on
geographic maps to assist with overall orientation, transmission system overviews provide the engineer or sys-
tem operator with real-time orientation of the current state of the power system. The step by step evolution of
the restoration plan can be displayed in substation and transmission overview diagrams. As components are
energized, they are colorized so that the extent of the electrical islands is apparent to the user. The transmission
overviews show the extent of electrical islands along with bus voltages and line flows.
With SRN 3.0, engineers and operators can focus on studying the benefits of different restoration methods.
SRN 3.0 takes care of the error prone routine switching operations efficiently and reliably. As an example, iso-
lating and building a path to restore power from gas turbines to a shutdown nuclear power plant might take
around 10 to 20 minutes in a real-time simulation. The system operator has to carefully open all the required
circuit breakers to clear the energization path. If one breaker is inadvertently left closed the island will blackout
