Distributed generation is gaining greater penetration levels in distribution grids due to government incentives for integrating distributed energy resources (DERs) and DER cost reductions. The frequency response of a grid-connected single inverter changes as other inverters are connected in parallel due to the couplings among grid inductance and/or inverter output filters. The selection of the inverter- or grid-side currents as feedback control signals is then not trivial because each one has tradeoffs. This paper analyses the system stability for multiple parallel- and grid-connected inverters using the inverter- or gridside currents as feedback signals. Modeling of both feedback signals is performedmore »
Method of Assessing Voltage Response of Inverter-Based Generation Due to System Faults
The increasing capacity from inverter-based resources (IBR) creates challenges for designing and operating electric power systems. In particular, wind and solar generation has very different characteristics compared to conventional turbo generators. This research investigates the critical clearing times for IBR as larger amounts of wind generation brought online. This paper develops a new six-bus transmission test systems for which multiple wind stations are interconnected. An exhaustive study of fault locations with respect to load levels and line impedances for a wide range of IBR penetration levels was performed with respect to inverter stability analysis to determine the corresponding critical clearing times. The results show that voltage stability at IBR points of interconnection can occur at not only higher penetration levels, but at lower penetrations as well.
- Award ID(s):
- Publication Date:
- NSF-PAR ID:
- Journal Name:
- IEEE Green Technologies Conference (GreenTech)
- Sponsoring Org:
- National Science Foundation
More Like this
Probabilistic Transient Stability Assessment of Power System Considering Wind Power Uncertainties and CorrelationsThis paper proposes a simple yet effective method for power system probabilistic transient stability assessment considering the wind farm uncertainties and correlations. Specifically, the inverse Nataf-transformation-based three-point estimation method and the Cornish-Fisher expansion have been integrated together to deal with the uncertainties and the correlations among different wind farms. Then, by resorting to the extended dynamic security region approach, the transient stability criterion is derived as a linear combination of nodal injection vector under a given fault condition. New indices for the identification of critical lines have also been developed. Extensive simulation results carried out on four different systems, includingmore »
Increased capacity associated with renewable energy sources has created a need for improved methods for controlling power flows from inverter-based generation. This research provides a comparative study of finite-control-set model predictive current control (FCS-MPC-based) with respect to conventional proportional-integral-based (PI-based) synchronous current control for a three-phase voltage source inverter (VSI). The inverter is accompanied by an inductive-capacitive-inductive (LCL) filter to attenuate pulse width modulation (PWM) switching harmonics. However, an LCL filter introduces a resonance near to the control stability boundary, giving rise to substantial complexity from a control perspective. In order to avoid potential instability caused by the resonance, activemore »
Security of a Power System Under High Penetration of Wind Energy Considering Contingencies and Stability MarginsSecurity is a well-known function to any transmission operator and system planner. As the world is moving toward the decarbonization of the power industry, it is more complicated for the system operators to maintain an acceptable level of security in the power system operation. More large-scale wind farms are being incorporated into the grid, and thus, the voltage stability concern is increasing. In practice, several contingencies are imagined by the system operators to assess the reliability of the grid. Since voltage stability is one of the major menaces that can trigger voltage instability in a power system, this paper ismore »
Virtual inertia based control of renewable energy sources (RESs) helps to enhance the frequency stability of power systems. In this paper, a Control Area Network (CAN) communication-based method is demonstrated to emulate virtual inertia using commercial off-the-shelf inverters. This allows the currently installed systems to be retrofitted with virtual inertia in a cost-effective manner which would allow for higher RES penetration in power systems. The proof-of-concept is demonstrated using a Xantrex XW6048 hybrid inverter/charger and OPAL-RT real-time digital simulator. Results show that CAN-based communication can be an effective way to reduce frequency variations in the power system.