A. M. Kulkarni

Professor Information

University

Indian Institute of Technology Bombay

Position

India

Citations(all)

1741

Citations(since 2016)

568

Cited By

1411

hIndex(all)

22

hIndex(since 2016)

13

i10Index(all)

39

i10Index(since 2016)

16

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Research & Interests List

Power System

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Top articles of A. M. Kulkarni

An Automatable Approach for Small-Signal Stability Analysis of Power Electronic-Based Power Systems Using EMT Companion Circuits

The increasing presence of power electronic (PE) controlled devices in power systems has widened the bandwidth of transients to be studied for grid stability. While these transients are normally studied using time-domain simulation (TDS), wide bandwidth linear time-invariant (LTI) state-space models are a useful complement to TDS for diagnostics, controller design and parametric analysis. A general automatable method to compute an LTI sampled-data model of a PE-based circuit is presented in this paper. The proposed method is based on the techniques employed in electro-magnetic-transient (EMT) programs to perform TDS of PE-based circuits. The method uses the building blocks of EMT nodal formulation such as conductance matrix of companion circuit and its LU factors computed during TDS, interpolation and chatter elimination corrections, and EMT model of the firing angle control system. The method …

Authors

Vinay Chindu,AM Kulkarni

Journal

IEEE Transactions on Power Delivery

Publish By

IEEE

Publish Date

2023/4/4

Analysis of the Transformer Failure using a Measurement-Simulation Approach: A Case Study

The diagnosis of transformer failures is based on various inputs, including the behaviour prior to failures (vibration, noise etc.), relay indications, and post-failure inspection/measurements. Condition monitoring tools like Frequency Response Analysis (FRA) may also provide early evidence of an evolving problem. Transformers are often subject to close-in faults, which may precipitate their failure. Current and voltage measurements corresponding to these events, obtained from relay fault recorders or disturbance records, can also be used in conjunction with analytical tools like simulation and electromagnetic field computation software to provide additional insights and corroborative evidence for the diagnosis. This is demonstrated using a real-life example of the failure of a 315 MVA, 400/220/33 kV auto-transformer at a 400 kV substation on the 14th of February 2018, following a close-in external fault.

Authors

Santosh V Singh,AM Kulkarni,HJ Bahirat,SV Kulkarni,PK Gargava

Journal

Journal International Association on Electricity Generation Transmission and Distribution

Publish By

International Association on Electricity Generation Transmission & Distribution

Publish Date

2023

Controller-Hardware-in-the-Loop Simulation Setup using a Real-Time Hybrid Simulator for Testing of Wide-area Damping Controllers

Poorly damped low-frequency inter-area electro-mechanical oscillations are a major concern in large synchronous grids. Embedded power electronic actuators such as HVDC and FACTS devices with wide-area damping controllers (WADCs) can be an effective solution to this problem. A WADC uses the synchrophasor measurements from the phasor measurement units (PMUs) installed across the system. This paper illustrates the controller-hardware-in-the-loop (CHIL) simulation setup for testing a WADC using a real-time hybrid simulator (RTHS). The RTHS does real-time co-simulation using a transient stability program (TSAT) and a real-time simulator that simulates electromagnetic transients. A two-area four-machine test system with an embedded HVDC link is used for demonstration.

Authors

KK Gajjar,Kapil Chauhan,AM Kulkarni

Publish By

IEEE

Publish Date

2022/12/17

Passivity of Electrical Power Networks Modelled Using Rectangular and Polar Variables

The proliferation of converter-interfaced distributed energy resources has highlighted the need for decentralized small-signal stability criteria for such interconnected systems. Passivity of the admittance based on rectangular D-Q variables is a promising grid-connectivity criterion for devices connected to the network. This is facilitated by the inherent passivity of the D-Q based impedance of the electrical network. However, this criterion has been found to be too restrictive for the connected devices that have voltage magnitude and frequency-dependent power injection characteristics. Therefore in this paper, alternative formulations involving polar variables and active and reactive power are examined. The results presented in this paper indicate that (a) the wide-band polar formulation of the network is not passivity compliant, and (b) the polar formulation is suitable for developing passivity-based stability criteria for low …

Authors

Kaustav Dey,AM Kulkarni

Publish By

IEEE

Publish Date

2022/12/17

A Proposal for a PMU Based Adaptive Islanding Scheme for Mumbai City

A major grid disturbance occurred in the Mumbai region on 12th October 2020. The Mumbai islanding scheme could not ensure survival for this disturbance even though it has operated successfully in the past. One of the reasons is that the ratio of embedded generation to load has fallen over the years. This has led to very high ROCOFs being encountered during islanding. To improve the chances of survival in high ROCOF scenarios, the existing settings need to be modified to avoid excessive delays, and frequency thresholds need to be increased. However, during low ROCOF scenarios, the existing scheme may largely be retained to ensure a more secure operation. A scheme to implement adaptive settings for high and low ROCOF scenarios using PMUs is proposed in this paper. Simulations are performed to demonstrate the efficacy of the proposed scheme.

Authors

PV Navalkar,AM Kulkarni,SV Singh,SA Soman

Publish By

IEEE

Publish Date

2022/12/17

Simplified Stability Assessment of Power Systems with Variable-Delay Wide-Area Damping Control

Power electronic devices such as HVDC and FACTS can be used to improve the damping of poorly damped inter-area modes in large power systems. This involves the use of wide-area feedback signals, which are transmitted via communication networks. The performance of the closed-loop system is strongly influenced by the delay associated with wide-area signals. The random nature of this delay introduces a switched linear system model. The stability assessment of such a system requires linear matrix inequality based approaches. This makes the stability analysis more complicated as the system size increases. To address this challenge, this paper proposes a delay-processing strategy that simplifies the modelling and analysis in discrete-domain. In contrast to the existing stability assessment techniques, the proposed approach is advantageous because the stability, as well as damping performance, can be …

Authors

KK Gajjar,Kaustav Dey,AM Kulkarni

Publish By

IEEE

Publish Date

2022/7/17

Wide Area Synchronous Disturbance Recording System

Synchrophasor based Wide Area Monitoring Systems are deployed at many places in the world. This paper discusses an extension to the existing WAMS infrastructure that measures phasor data to also obtain instantaneous values in a time synchronous manner over a wide area. Extensions are made by utilizing user definable fields in the command and data frames of the synchrophasor standard C37.118 2011 Part 2. A practical implementation of the proposed extension in a free and open source PMU simulator, PDC, integrated COMTRADE reader and historian is demonstrated. A possible application of such a system is presented.

Authors

Sancho Simmy Louis,Faizan Feroz,Gopal Gajjar,AM Kulkarni

Publish By

IEEE

Publish Date

2021/12/16

Testing of WAMS-based Supervised Zone-3 Distance Relay Protection Scheme using a Real-Time Digital Simulator

Power swings, load encroachment, and low voltage conditions can cause false tripping due to the Zone-3 backup protection feature of a distance relay. To avoid this, a distance relay can be supervised using the measurements from Phasor Measurement Units (PMUs) of a Wide Area Measurement System (WAMS). The algorithm and software for this purpose was developed. Through the monitoring of differential currents of the backed-up lines, the software generates Block and Trip signals which are communicated to the relay. This paper presents the results of testing of this scheme using a real-time digital simulator. Different fault scenarios in a four-machine ten bus system were simulated. The results indicate that the scheme is effective in preventing the false tripping of distance relays.

Authors

KK Gajjar,AM Kulkarni,Gopal Gajjar,SA Soman,Rajeev Gajbhiye

Publish By

IEEE

Publish Date

2021/12/16

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