IEEE Electrification - September 2022 - 14

are replaced by power electronic inverters, the dynamics
of the resulting power system are determined by the
software of the inverters-for example, the control structures
and parameters for GFM and grid-following IBRs.
Moreover, the dynamics become much faster because
power electronic inverter controls respond much faster
to voltage and current changes at their connection point
compared to SG controls.
The power system dynamics become time varying
because of the intermittent generation from renewable
sources. Over the course of a day, the ratio of SG-based to
inverter-based generation changes, as does the geographical
location of online synchronous and inverter-based
generation as illustrated for Hawai'i Island in Figure 2.
Dynamic Performance Optimization
Critical
Contingencies
Tuned Controller
Parameters
Dynamic Security Assessment
SIGUARD DSA
State Estimate
EMS
Validated Controller
Parameters
Spectrum Power EMS
RTU
Measurements
Validated Controller
Parameters
Figure 3. An architecture overview of the operator support system
(OSS). EMS: energy management system; RTU: remote terminal unit.
Operator Support System for N-1 Security
To solve these structurally different N-1 security challenges,
the project team has developed an online operator
support system (OSS) comprising dynamic security
assessment and DPO to achieve N-1 security as the generation
mix changes (see Figure 3). This OSS has been implemented
and validated in a demonstrator consisting of a
high-fidelity, real-time simulation of the power system of
Hawai'i Island in OPAL-RT eMEGASIM, the commercial
energy management system (EMS) Spectrum Power™ 7,
the commercial dynamic security assessment tool
SIGUARD®DSA, and a custom implementation of DPO.
Figure 4 shows the operation scheme of the OSS. It
builds on standard EMS functions for state estimation
from remote terminal unit (RTU) measurements. The OSS
first utilizes the state estimate to identify critical contingencies
using dynamic security assessment (DSA). This is
achieved by the fast parallel simulation of critical N-1 contingencies
such as generator or power line outages, starting
from the current system state. If the assessment finds
that some contingencies lead to unacceptable power oscillations
or even blackouts, DPO is executed to tune the controller
parameters of different generation assets such as
IBRs and conventional power plants (see Figure 5 for
details). The optimized parameters are then validated by
re-executing the dynamic security assessment. If this
EMS
Operator Support System
State Estimation
Identify Critical
Contingencies
Tune Controllers to
Mitigate Contingencies
Validation of New
Controller Parameter
Spectrum Power 7
SIGUARD DSA
Dyn. Performance Opt.
SIGUARD DSA
RTU Measurements
Validated Controller Parameters
Figure 4. An operation scheme for a dynamic N-1 security assessment and DPO.
14
IEEE Electrification Magazine / SEPTEMBER 2022
Power System
Operator Support
System
IEEE Electrification - September 2022

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