The voltage source converter VSC mimicking the behavior of a synchronous machine provides many advantages for grid operation. This “virtual synchronous generator (VSG)” will be implemented as a real-time simulator model on the RTDS simulator and used to investigate several operating scenarios.
The VS G behaves like a synchronous machine, which is one of the most widely used components of the legacy power system, and so it is well understood. The VSG can provide inertia and damping to the network.
With increased levels of series compensation of transmission lines (Which is the most economical solution for bulk power transmission over long distances) and with more power electronic controllers such as HVDC, FACTS and converter based distributed generation in the power network, Sub Synchronous Interaction (SSI) problems arise. It is necessary to identify different types of SSI that could occur in the power network through proper means and to prevent such at the design stage or to take counter measures if required.
Voltage instability is one of the major causes of many blackouts such as Canada-United State blackout (2003), Sweden-Denmark blackout (2003), India blackout (2012), and Turkey blackout (2015). If reliable methods are available for online voltage stability assessment, operators can be warned and automated corrective actions can be initiated to prevent voltage collapse. Although, a large number of Voltage Stability Indices (VSIs) are reported in literature, they are not practically applicable for real-time monitoring or not sufficiently reliable under all operating conditions.
In this research, a new approach to efficiently simulate large RLC represent power systems will be introduced and implemented in RTDS. The new approach utilize principle component analysis to search the subspace of state space vectors corresponding to a customer designed frequency band excitations and using projection method to form the reduced order system. Unlike other frequency dependent network equivalent methods, the proposed method reserves all internal information of original system and also inherently guarantees the passivity of the equivalent network.
Modern power systems wherein renewable energy sources are prevalent will exhibit larger frequency deviations than conventional power systems due to the diluted share of conventional generation based upon large electric machines with massive spinning rotors. To combat this, power-electronic converters that are used to interface renewable sources need to provide ancillary, such as frequency support and inertia emulation. This research will investigate this functionality for a class of power-electronic converters, namely modular multilevel converters.
The widespread use of phasor measurement units (PMUs) in power-grids can greatly enhance state-estimation (SE) by making use of accurate, GPS time-stamped synchronous phasor measurements. Unlike conventional SCADA measurements which are reported every 4 seconds, synchro-phasor measurements are typically available as frequently as 30-60 measurements per second. While the availability of more measurements can provide accurate state estimates in real-time, the sheer amount of data can overwhelm the computational capabilities of most data processing systems.
Batteries are becoming popular options for storage of energy at large scales for application in power systems. A battery energy storage system may be developed using batteries of different chemistries and also batteries that are not necessarily at the same state of health. The capabilities of a battery energy storage system are affected by the characteristics of the batteries that form it. Therefore, it is essential that a storage systems be developed and operated with a full understanding of how these differences affect its performance.
As a result of the advancement of renewable energy and power electronic (PE) converter technologies, renewable energy sources are increasingly interfaced to the grid through PE based interconnections such as Voltage Sourced Converters (VSC) and Modular Multi-level Converters (MMC). It is essential to model and predict the behavior and effects of these components in the power system for safe and reliable operation. This proposed research project will focus on how renewable sources connected to the grid through PE converters, affect the stability power transmission system.
Protection systems perform vital function in power distribution systems to ensure safety of public and equipment during network faults, and usually designed assuming a single power source supply. Distributed Energy Resources (DERs) are fast becoming an integral part of most Electric Power Systems around the world. Improvement in reliability, efficiency, power quality, and reduction in greenhouse emissions are some of the reasons behind this.
By creating real-time and hardware porotypes, the proposed research provides opportunities for better investigation of these converters and for development of advanced and effective methods for their control. The three interns that will be trained during this research partnership will gain in-depth knowledge of modern power system equipment and knowledge of the latest developments in real-time simulation of such systems.