Showing papers by "Rajiv K. Varma published in 2019"

PV Solar System Control as STATCOM (PV-STATCOM) for Power Oscillation Damping

Abstract: This paper presents a novel control of photovoltaic (PV) solar system as a FACTS device STATCOM, termed PV-STATCOM, for power oscillation damping (POD) in transmission systems. In the proposed control, as soon as power oscillations due to a system disturbance are detected, the solar farm discontinues its real power generation function very briefly (few tens of seconds) and makes its entire inverter capacity available to operate as a STATCOM for POD. As soon as power oscillations are damped, the solar farm restores real power output to its pre-disturbance level in a ramped manner, while keeping the damping function activated. This results in much faster restoration than that specified in grid codes. During nighttime, the solar farm performs POD with its entire inverter capacity. It is shown from EMTDC/PSCAD simulations that the proposed control provides significant increase in power transfer capacity on a 24/7 basis in systems that exhibit both local inertial and interarea oscillatory modes. The proposed PV-STATCOM is about 50–100 times cheaper than an equivalent STATCOM for providing POD at the same location. This novel control can potentially bring large savings for transmission utilities and open up a new revenue making opportunity for solar farms for providing POD.

Enhancement of Solar Farm Connectivity With Smart PV Inverter PV-STATCOM

Abstract: This paper presents an innovative smart PV inverter control as STATCOM (PV-STATCOM) for obviating the need for a physically connected STATCOM in a distribution network for controlling steady-state voltage and temporary over voltages (TOVs) resulting from unsymmetrical faults. Two 10-MW PV solar systems are already connected in the distribution feeder of a utility in Ontario, Canada. A STATCOM is installed to prevent the steady-state voltage and TOV issues arising from the connection of a third 10-MW PV solar farm at same bus. It is demonstrated from PSCAD electromagnetic transient studies that if the proposed PV-STATCOM control is implemented on the incoming third 10-MW PV solar farm, all the above voltage issues are mitigated satisfactorily as required by the utility grid code. This proposed smart inverter PV-STATCOM control therefore eliminates the need for the physical STATCOM, saving an enormous cost for utilities dealing with voltage rise and TOV issues with grid-connected PV systems. Such a control can effectively increase the distributed generator hosting capacity of distribution feeders at more than an order of magnitude lower cost under similar network conditions. Moreover, this novel grid support functionality can open new revenue making opportunities for PV solar farms.

First in Canada, Night and Day Field Demonstration of a New Photovoltaic Solar-Based Flexible AC Transmission System (FACTS) Device PV-STATCOM for Stabilizing Critical Induction Motor

Abstract: Photovoltaic (PV) solar farms are typically dormant at nighttime with their entire expensive assets unused. This paper presents the first in Canada (and perhaps first in the world) utility demonstration of a novel nighttime and daytime technology of utilizing PV solar farm as a dynamic reactive power compensator (STATCOM), and named PV-STATCOM. The field demonstration was performed on a 10 kW PV solar farm installed in the utility network of Bluewater Power Distribution Corporation, in Sarnia, Ontario. It is demonstrated that the solar farm autonomously transforms into a STATCOM and ensures continuous stable operation of a critical induction motor during large disturbances which would otherwise destabilize the motor. The PV-STATCOM is thus shown to be a new FACTS device STATCOM which provides a 24/7 dynamic voltage control functionality as a STATCOM but is about 50 times less costly than an actual equivalent sized STATCOM. The PV-STATCOM is further demonstrated to be a new smart inverter which operates much faster than a conventional smart inverter and also during nighttime, which present-day smart inverters do not. Shutdown of critical induction motors used in industries such as petrochemicals, process control, mining, automotive, medicines, etc. can result in significant financial loss to the industries. This novel functionality of critical motor stabilization by solar farms as PV-STATCOM can potentially open a substantial new revenue earning opportunity for solar farms in addition to generation of active power. This paper presents the first stage results of field demonstration of PV-STATCOM technology on 13th Dec. 2016, in an ongoing project.

Reduction in System Losses and Power Demand by Combination of Optimal Power Flow and Conservation Voltage Reduction Using Smart PV Inverters

Abstract: This paper presents a new control methodology of smart PV inverters that combines Optimum Power Flow (OPF) and Conservation Voltage Reduction (CVR) in a single step for reduction of system active power demand as well as active power losses in distribution systems. The methodology has been implemented in two different types of distribution systems simulated in PSS®E. The study also underscores the added benefits pertaining to active power demand reduction, that can be extracted out of PV systems in addition to their primary function of real power generation.