Srinivas Bhaskar Karanki

Bio: Srinivas Bhaskar Karanki is an academic researcher from Indian Institute of Technology Bhubaneswar. The author has contributed to research in topics: Topology (electrical circuits) & Boost converter. The author has an hindex of 9, co-authored 37 publications receiving 396 citations. Previous affiliations of Srinivas Bhaskar Karanki include Indian Institutes of Technology & Indian Institute of Technology Madras.

A DSTATCOM Topology With Reduced DC-Link Voltage Rating for Load Compensation With Nonstiff Source

Abstract: The distribution static compensator (DSTATCOM) is used for load compensation in power distribution network. In this paper, a new topology for DSTATCOM applications with nonstiff source is proposed. The proposed topology enables DSTATCOM to have a reduced dc-link voltage without compromising the compensation capability. It uses a series capacitor along with the interfacing inductor and a shunt filter capacitor. With the reduction in dc-link voltage, the average switching frequency of the insulated gate bipolar transistor switches of the DSTATCOM is also reduced. Consequently, the switching losses in the inverter are reduced. Detailed design aspects of the series and shunt capacitors are discussed in this paper. A simulation study of the proposed topology has been carried out using power systems computer-aided design simulator and the results are presented. Experimental studies are carried out to verify the proposed topology.

Particle Swarm Optimization-Based Feedback Controller for Unified Power-Quality Conditioner

Abstract: The unified power-quality conditioner (UPQC) is used to provide balanced and sinusoidal source currents and load voltages under unbalanced and distorted three-phase supply voltages and load currents in a power distribution network. In this paper, a particle swarm optimization-based feedback controller is designed for UPQC. This feedback controller has optimal performance in various operating conditions and is robust to parametric uncertainties when compared to the conventional feedback controllers, such as the linear quadratic regulator. The proposed method is implemented on a distribution system and detailed simulation and experimental results are presented.

Optimal location of battery energy storage systems in power distribution network for integrating renewable energy sources

Abstract: The major challenge in integrating the Battery Energy Storage System (BESS) and renewable energy sources with the existing power system network is to determine the capacity and placement of the BESS in the system. The installation of BESS units at non optimal places can result in an increase in cost, including the system losses and larger battery capacity and therefore, having an effect opposite to the desired. For this reason, the use of a methodology capable of analyzing the influence on some system characteristics of BESS allocation and sizing is very useful for system planning. In this paper, a loss sensitivity based algorithm is proposed for optimal placement and size of the BESS in the distribution system to reduce the distribution power loss. IEEE distribution test data has been used to show the performance of the proposed algorithm.

Optimal capacity and placement of battery energy storage systems for integrating renewable energy sources in distribution system

Abstract: Battery energy storage can bring benefits to multiply stakeholders in the distribution system. The integration of the Battery Energy Storage System (BESS) and renewable energy sources with the existing power system networks has many challenges. One of the major challenges is to determine the capacity and connection location of the BESS in the distribution system. The installation of BESS units at suboptimal places may increase the cost, including system losses and installation of larger battery capacity. So, it is essential to have a method capable of analyzing the influence of BESS allocation and sizing on power distribution system performance. In this paper, a loss sensitivity based algorithm is proposed for optimal placement of the BESS in the distribution system to reduce the distribution system losses. This paper also presents an algorithm for determining the optimal size of the BESS using particle swarm optimization technique. An electrical distribution utility system data in Ontario have been used to show the performance of the proposed algorithm.

Synchronous reference frame based current controller with SPWM switching strategy for DSTATCOM applications

Abstract: This paper presents sine pulse width modulation (SPWM) based switching strategy for two-level neutral-point-clamped (NPC) voltage source inverter (VSI), used in distribution static compensator (DSATCOM) for unbalanced nonlinear load compensation. DSTATCOM, is used for supplying harmonic currents and reactive power to unbalanced nonlinear loads. Thus, making the utility current balanced and sinusoidal with unity power factor (UPF) operation. Synchronous rotating (dq0) frame current controller with decoupled d, q and 0 components are used for generating the control signals, which are further used for developing gating signals for VSI using SPWM switching strategy. Neutral current compensation, which corresponds to ‘0’ axis component in dq0 frame is carried out for proper compensation of unbalanced nonlinear loads. Synchronous reference (dq0) frame theory is used for reference filter currents generation. A detailed simulation study to understand the compensation performance of DSTATCOM with dq0 current control under steady state and dynamic conditions are carried out using PSCAD 4.2.1 simulator, and the corresponding results are presented.

Enhancing Electric Power Quality Using UPQC: A Comprehensive Overview

Abstract: This paper presents a comprehensive review on the unified power quality conditioner (UPQC) to enhance the electric power quality at distribution levels. This is intended to present a broad overview on the different possible UPQC system configurations for single-phase (two-wire) and three-phase (three-wire and four-wire) networks, different compensation approaches, and recent developments in the field. It is noticed that several researchers have used different names for the UPQC based on the unique function, task, application, or topology under consideration. Therefore, an acronymic list is developed and presented to highlight the distinguishing feature offered by a particular UPQC. In all 12 acronyms are listed, namely, UPQC-D, UPQC-DG, UPQC-I, UPQC-L, UPQC-MC, UPQC-MD, UPQC-ML, UPQC-P, UPQC-Q, UPQC-R, UPQC-S, and UPQC-VA. More than 150 papers on the topic are rigorously studied and meticulously classified to form these acronyms and are discussed in the paper.

Lithium-Ion Battery Storage for the Grid—A Review of Stationary Battery Storage System Design Tailored for Applications in Modern Power Grids

Abstract: Battery energy storage systems have gained increasing interest for serving grid support in various application tasks. In particular, systems based on lithium-ion batteries have evolved rapidly with a wide range of cell technologies and system architectures available on the market. On the application side, different tasks for storage deployment demand distinct properties of the storage system. This review aims to serve as a guideline for best choice of battery technology, system design and operation for lithium-ion based storage systems to match a specific system application. Starting with an overview to lithium-ion battery technologies and their characteristics with respect to performance and aging, the storage system design is analyzed in detail based on an evaluation of real-world projects. Typical storage system applications are grouped and classified with respect to the challenges posed to the battery system. Publicly available modeling tools for technical and economic analysis are presented. A brief analysis of optimization approaches aims to point out challenges and potential solution techniques for system sizing, positioning and dispatch operation. For all areas reviewed herein, expected improvements and possible future developments are highlighted. In order to extract the full potential of stationary battery storage systems and to enable increased profitability of systems, future research should aim to a holistic system level approach combining not only performance tuning on a battery cell level and careful analysis of the application requirements, but also consider a proper selection of storage sub-components as well as an optimized system operation strategy.

On the Inertia of Future More-Electronics Power Systems

Abstract: Inertia plays a vital role in maintaining the frequency stability of power systems. However, the increase of power electronics-based renewable generation can dramatically reduce the inertia levels of modern power systems. This issue has already challenged the control and stability of small-scale power systems. It will soon be faced by larger power systems as the trend of large-scale renewable integration continues. In view of the urgent demand for addressing the inertia concern, this paper presents a comprehensive review of inertia enhancement methods covering both proven techniques and emerging ones and also studies the effect of inertia on frequency control. Among those proven techniques, the inertia emulation by wind turbines has successfully demonstrated its effectiveness and will receive widespread adoptions. For the emerging techniques, the virtual inertia generated by the dc-link capacitors of power converters has a great potential due to its low cost. The same concept of inertia emulation can also be applied to ultracapacitors. In addition, batteries will serve as an alternative inertia supplier, and the relevant technical challenges as well as the solutions are discussed in this paper. In future power systems where most of the generators and loads are connected via power electronics, virtual synchronous machines will gradually take over the responsibility of inertia support. In general, it is concluded that advances in semiconductors and control promise to make power electronics an enabling technology for inertia control in future power systems.

Load compensating DSTATCOM in weak AC systems

Abstract: The paper discusses load compensation using a distribution static compensator (DSTATCOM). It is assumed that the DSTATCOM is associated with a load that is remote from the supply. It is shown that the operation of a DSTATCOM assuming that it is connected to a stiff source in such situations will result in distortions in source current and voltage at the point of common coupling. To avoid this, the DSTATCOM is connected in parallel with a filter capacitor that allows the high frequency component of the current to pass. However, this generates control issues in tracking, as standard controls such as a hysteresis control are not suitable in these circumstances. This paper proposes a new switching control scheme and demonstrates its suitability for this problem. It also proposes a scheme in which the fundamental sequence components of a three-phase signal can be computed from its samples. The overall performance of the proposed scheme is verified using digital computer simulation studies.

Review on the optimal placement, sizing and control of an energy storage system in the distribution network

Abstract: Energy storage system (ESS) has developed as an important element in enhancing the performance of the power system especially after the involvement of renewable energy based generation in the system. However, there are a few challenges to employ ESS in distribution network, one of which is to ensure the best location and capacity so as to take the full advantage of installing ESS in the grid. In this paper, an extensive literature review on optimal allocation and control of ESS is performed. Besides, different technologies and the benefits of the ESS are discussed. Some case studies of ESS application in different part of the world are also presented. Finally, this paper emphasizes the future improvement of ESS control and performance to solve more complicated problems originated from the participation of renewable energy generation in the power system.