The research conducted at ASPIRES broadly spans the following topics:
Electric power quality is concerned with supplying and delivering electric power to end user equipment in a manner that is suitable to the operation of the equipment. Many power quality problems arise from incompatibilities between electrical supply characteristics and equipment loads. This can include power outages, voltage variations, overvoltage transients, harmonic resonance, and voltage flicker.
In recent years, due to the increased use of new types of loads, concern about power quality problems has grown. Furthermore, the integration of smart grid technologies such as electric vehicles (EVs), distributed generation technologies (DGs), energy storage, etc., into distribution circuit can further deteriorate system power quality (PQ). The future distribution grid should be able to accommodate these loads and simultaneously provide desired power quality to the customers. Our lab specializes in studying current and future potential power quality concerns. Specific research areas include:
- Time-domain modeling and simulation of power systems electromagnetic transient phenomena
- Power quality analysis and solutions: voltage sags, transients and harmonics
- Detection and classification of power quality events
- Fault location and analysis
- Intelligent systems for power quality assessment and diagnostics
- Autonomous intelligent monitoring and assessment systems, predictive maintenance, self-optimizing and reconfiguration of distribution systems
Wind Power Integration
Increasing penetration of wind power raises concerns regarding its impact on the power system. Operating wind turbines in weak distribution circuits or isolated microgrids may cause power fluctuations or unbalanced power problems due to the variation of wind speed. Capacitor banks, voltage regulators, static var compensators (SVCs), and static synchronous compensators (STATCOMs) may be required to regulate these fluctiations. Wind turbines can also contribute to harmonic problems. Specific research areas include:
- Modeling and simulation of wind turbines and wind power plants for load flow, dynamic stability, and electromagnetic transient studies
- Control of wind turbines
- Short-circuit contribution form wind turbines
- Impact of wind farms on transmission and distribution systems
- Capacity value and wind power firming
Solar PV Integration
The decrease in capital cost of rooftop photvoltaic (PV) panels and expansion of available subsidies have promoted a significant increase in PV installations in some parts of US, such as California, Hawaii and Arizona. With a further decreasing trend in capital costs of PV, it is expected that the total PV installations will increase over time. However, high PV penetration in the distribution grid can create voltage and protection related concerns. The research in this field involves:
- Estimating maximum PV capacity that can be integrated in a given distribution grid
- Mitigating the impacts of high PV penetration with the help of smart inverters and energy storage
- Evaluating the total cost of increasing the PV penetration in a distribution grid
- Analysis of overcurrent protection issues arising due to high PV penetration in a distribution grid
Power electronics is related to the implementation of semi-conductor devices such as diodes, thyristors, IGBTs or MOSFETs to convert and deliver electric power. The use of power electronics in the power system has significantly grown in the last few decades to improve the grid system efficiency and reliability. The semiconductor devices are also utilized in the high-voltage direct current (HVDC) system for the bulk transmission of electric power. Additionally, power electronics applications in the transmission system can be found in various shunt and series compensators such as static compensator (STATCOM), thyristor controlled series compensator (TCSC), and other flexible AC transmission system (FACTS) controllers. In the distribution level, power electronics appears in the static circuit breaker (SCB) device, dynamic voltage restorer (DVR), and unified power quality conditioner (UPQC).
With the increasing usage of renewable energy generation, such as wind and photovoltaic, the penetration of these energy sources and consequently the power electronics devices raises challenges in power system stability and voltage quality. Our lab research focuses on the effects of power electronics integrated into the grid. This research also includes the development of power electronics devices that can diagnose and manage the power quality.