Showing papers by "Rajiv K. Varma published in 2018"

PV-STATCOM: A New Smart Inverter for Voltage Control in Distribution Systems

Abstract: This paper presents a novel smart inverter PV-STATCOM in which a photovoltaic inverter can be controlled as a dynamic reactive power compensator—STATCOM. The proposed PV-STATCOM can be utilized to provide voltage control during critical system needs on a 24/7 basis. In the night-time, the entire inverter capacity is utilized for STATCOM operation. During a critical system disturbance in the daytime, the smart inverter discontinues its real power generation function temporarily (for about a few seconds), and releases its entire inverter capacity for STATCOM operation. Once the disturbance is cleared and the need for grid voltage control is fulfilled, the solar farm returns to its predisturbance real power production. The low voltage ride through (LVRT) performance of the PV-STATCOM is demonstrated through both EMTDC/PSCAD simulations and laboratory implementation using dSPACE control. This proposed PV-STATCOM with a response time of 1–2 cycles can provide an equivalent service as an actual STATCOM in a given application and possibly seek revenues for providing this service.

PV-STATCOM – A New Smart Inverter for Voltage Control in Distribution Systems

Abstract: This paper presents a novel smart inverter PV-STATCOM in which a PV inverter can be controlled as a dynamic reactive power compensator - STATCOM. The proposed PV-STATCOM can be utilized to provide voltage control during critical system needs on a 24/7 basis. In the nighttime, the entire inverter capacity is utilized for STATCOM operation. During a critical system disturbance in the daytime, the smart inverter discontinues its real power generation function temporarily (for about a few seconds), and releases its entire inverter capacity for STATCOM operation. Once the disturbance is cleared and the need for grid voltage control is fulfilled, the solar farm returns to its pre-disturbance real power production. The Low Voltage Ride Through (LVRT) performance of the PVSTATCOM is demonstrated through both EMTDC/PSCAD simulations and laboratory implementation using dSPACE control. This proposed PV-STATCOM with a response time of 1-2 cycles, can provide an equivalent service as an actual STATCOM in a given application and possibly seek revenues for providing this service.

Control of STATCOMs – A Review

Abstract: This IEEE Working Group paper presents a review of selected journal papers published on control of STATCOM – a Flexible AC Transmission System (FACTS) device, during the period 2016-2017. This review includes STATCOM controls utilized in different applications such as voltage control, stability improvement, mitigation of subsynchronous resonance (SSR), integration of renewable energy systems, energy storage systems, and coordination with HVDC systems. Journal papers have been searched through different search engines such as, IEEE Xplore, SCOPUS and others. This review includes papers published during 2016 to October 2017 (until the submission of this Review paper). The total journal papers found in this search were 260, of which only 75 were found through IEEE Xplore, while the remaining 170 were discovered from other non-IEEE search engines. Due to the page limitation, a total of 60 papers are included in this Bibliography. The bibliographic citations of the remaining papers will be provided on the website of this IEEE Working Group. The objective of this Working Group paper is to disseminate information and thereby educate the power and energy systems community worldwide about the controls of STATCOMs for providing various grid benefits.

Increasing Hosting Capacity of PV Solar Systems using Smart Inverter Volt-Var Control

Abstract: The steady state voltage rise caused by reverse power flows and intermittency in renewable power is the main limiting factor for integration of distributed generators in medium and low voltage distribution lines. With the advancement in smart inverter technologies, the Volt-Var control using the remaining capacity of the inverter can be used to provide effective voltage control in distribution systems. In this paper, the efficacy of Volt-Var control on two PV solar farms connected to a realistic feeder in Ontario, Canada, is demonstrated for increasing the hosting capacity up to the thermal limit of the feeder. Implementation of such smart inverter controls will greatly help in the integration of PV solar systems in power grids.

A Novel Reactive Power based Frequency Control by PV-STATCOMs during Day and Night

Abstract: This paper presents a novel reactive power-based frequency support service through large-scale PV plants. Frequency is conventionally controlled through real power, which may not be always available from PV solar systems. In addition, PV power may need to be curtailed during high power production periods (e.g. noontime) for frequency support. On the other hand, reactive power is always available, which provides the PV plants with the opportunity of being controlled as a STATCOM, known as PV-STATCOM both during night and day. Although less effective, reactive power can also influence the system frequency through modulation of voltages at the terminals of loads. This paper investigates the feasibility, challenges and effectiveness of Reactive power-based Frequency Controller (RFC) added to PV-STATCOMs. The proposed controller aims to enhance the stability of the "frequency regulation mode" of the system. The design of RFC through small signal residue-based technique and time domain simulations are performed in Matlab to demonstrate the benefits of the proposed control in a two-area power system. This novel control of PV solar farms as PV-STATCOM can effectively complement the frequency support from other generators in the power grid, on a 24/7 basis.