B.C. Pal

Imperial College London | Imperial

A model predictive control (MPC) method for enhancing post-fault transient stability of a grid-forming (GFM) inverter-based resources (IBRs) is developed in this paper. This proposed controller is activated as soon as the converter enters into the post-fault current-saturation mode. It aims at mitigating the instability arising from insufficient de...

A detailed multi-time scale model of synchronous machines (SM) with stator transients is necessary to capture the complex interactions in inverter-integrated power systems. The conventional detailed SM model, including stator transients, is incompatible with that of the step-up transformer in the dq domain as both are modeled as current sources in...

p>The significance of system inertia, especially its nonuniform spatial distribution, is becoming paramount in the current power system scenario. This paper proposes a generalized two-level method to estimate the spatial inertia distribution, which is applicable for any given operating condition (or snapshot), as well as for ambient and transient p...

p>The significance of system inertia, especially its nonuniform spatial distribution, is becoming paramount in the current power system scenario. This paper proposes a generalized two-level method to estimate the spatial inertia distribution, which is applicable for any given operating condition (or snapshot), as well as for ambient and transient p...

The displacement of conventional synchronous generation by Inverter-Based Resources (IBRs) poses critical challenges to the frequency stability of Renewable Energy (RE) integrated power systems. An increased shift towards green energy by integrating RE sources that provide little or no inertia results in a high Rate of Change of Frequency (RoCoF) a...

When urban distribution networks are gradually modernised, the overhead lines are replaced by underground cables, whose shunt admittances can not be ignored. Traditional power flow (PF) model with ? equivalent circuit shows nonconvexity and long computing time, and most recently proposed linear PF models assume zero shunt elements. All of them are...

This paper considers detailed modeling of gear backlash in the drivetrains of a type-3 turbine-based windfarm in an interconnected power system. The detailed model has been used to: (a) thoroughly investigate the impact of backlash on the dynamic performance and response of the windfarm; (b) identify the nature of various modes and the change of th...

p>In an era where high-frequency flying capacitor (FC) multilevel inverters (MLIs) are increasingly gaining attention in energy conversion systems that push the boundaries of power density, the need for a compact, fast, and accurate FC voltage monitoring system is also increasing. In this article, we designed and developed a new FC measurement syst...

The emergence of wide bandgap power devices has brought the attention back to the flying capacitor (FC) multilevel inverters with a large number of stages, in an effort to increase the power density by minimizing the passive components. The main challenge that such systems face, particularly the ones based on high-frequency Gallium-Nitride devices...

Inverter-based resources (IBRs) are required to provide dynamic voltage support (DVS) during voltage dips to enhance the low-voltage ride-through capability. In this paper, we develop a model-free control method to achieve the optimal DVS (ODVS) without relying on the knowledge of grid parameters. Delving into the optimum trajectory of the ODVS pro...

Nonlinear excitation controllers for power systems are considered as promising replacements for their linear counterparts, such as power system stabilizers (PSSs). However, Lyapunov based nonlinear controllers currently available in literature have been derived using simplified third order machine dynamics and have not been tested on realistic powe...

p>This paper presents a systematic approach for a detailed positive sequence dq domain modeling and simulation of low inertia power systems for system stability and transients analysis. It aims to reduce the computational complexities while maintaining simulation accuracy comparable to electromagnetic transient (EMT) programs. The proposed approach...

p>This paper presents a systematic approach for a detailed positive sequence dq domain modeling and simulation of low inertia power systems for system stability and transients analysis. It aims to reduce the computational complexities while maintaining simulation accuracy comparable to electromagnetic transient (EMT) programs. The proposed approach...

With the fast expansion of the power grid and increasing complexity due to modern equipment, power flow models with non-convexity and long computing time are not suitable for network calculation and optimization problems. Therefore, this paper proposes a linearized branch flow model (LBF) considering line shunts (LBFS). The strength of LBF lies in...

With the fast expansion of the power grid and increasing complexity due to modern equipment, power flow models with non-convexity and long computing time are not suitable for network calculation and optimization problems. Therefore, this paper proposes a linearized branch flow model (LBF) considering line shunts (LBFS). The strength of LBF lies in...

With the fast expansion of the power grid and increasing complexity due to modern equipment, power flow models with non-convexity and long computing time are not suitable for network calculation and optimization problems. Therefore, this paper proposes a linearized branch flow model (LBF) considering line shunts (LBFS). The strength of LBF lies in...

As one of the most significant part of carbon neutralisation, the rapid growth of electric vehicle (EV) market in past few years has greatly expedited the transport electrification, which, however, has brought in new challenges to power system including isolated distribution network for commercial and industrial set up. Stochastic and complex EV be...

With diminishing fossil fuel resources and increasing environmental concerns, large-scale deployment of Renewable Energy Sources (RES) has accelerated the transition towards clean energy systems, leading to significant RES generation share in power systems worldwide. Among different RES, solar PV is receiving major focus as it is most abundant in n...

This paper investigates the dynamic voltage support (DVS) from inverter-based resources (IBRs) under voltage sags to enhance the low-voltage ride-through performance. The DVS problem is formulated as a nonconvex optimization program that maximizes the positive-sequence voltage magnitude at the point of common coupling (PCC) subject to the current,...

Dynamic state estimation (DSE) accurately tracks the dynamics of a power system and provides the evolution of the system state in real-time. This paper focuses on the control and protection applications of DSE, comprehensively presenting different facets of control and protection challenges arising in modern power systems. It is demonstrated how th...

In this paper, we investigate the control of inverter-based resources (IBRs) for optimal voltage unbalance attenuation (OVUA). This problem is formulated as an optimization program under a tailored dq-frame, which minimizes the negative-sequence voltage at the point of common coupling (PCC) subject to the current, active power, synchronization stab...

div>This paper proposes a completely non-centralized Volt/VAr control (VVC) algorithm for active distribution networks which are faced with voltage magnitude violations due to the high penetration of solar photovoltaics (PVs). The proposed VVC algorithm employs a two-stage architecture where the settings of the classical voltage control devices (VC...

div>This paper proposes a completely non-centralized Volt/VAr control (VVC) algorithm for active distribution networks which are faced with voltage magnitude violations due to the high penetration of solar photovoltaics (PVs). The proposed VVC algorithm employs a two-stage architecture where the settings of the classical voltage control devices (VC...

Since the publication of the original paper on power system stability definitions in 2004, the dynamic behavior of power systems has gradually changed due to the increasing penetration of converter interfaced generation technologies, loads, and transmission devices. In recognition of this change, a Task Force was established in 2016 to re-examine a...

p>Grid-forming control (GFC) for photovoltaic (PV) systems is seen lately as a promising solution for enhanced grid support and improved power system stability. However, various factors, such as the non-monotonic nature of the power-voltage (P-V) characteristic and the maximum power point (MPP) estimation accuracy, affect the controller performance...

This paper investigates the dynamic voltage support (DVS) control of inverter-based resources (IBRs) under voltage sags to enhance the low-voltage ride-through performance. We first revisit the prevalent droop control from an optimization perspective to elaborate on why it usually suffers from suboptimality. Then, we formulate the DVS problem as an...

This report of TF on dynamic state and parameter estimation aims to 1) clearly review its motivations and definitions, demonstrate its values for enhanced power system modeling, monitoring, operation, control and protection as well as power engineering education; 2) provide recommendations to vendors, national labs, utilities and ISOs on the use of...

This report of TF on dynamic state and parameter estimation aims to 1) clearly review its motivations and definitions, demonstrate its values for enhanced power system modeling, monitoring, operation, control and protection as well as power engineering education; 2) provide recommendations to vendors, national labs, utilities and ISOs on the use of...

Power system dynamic state estimation (DSE) remains an active research area. This is driven by the absence of accurate models, the increasing availability of fast-sampled, time-synchronized measurements, and the advances in the capability, scalability, and affordability of computing and communications. This paper discusses the advantages of DSE as...

Dynamic state estimation (DSE) accurately tracks the dynamics of a power system and provides the evolution of the system state in real-time. This paper focuses on the control and protection applications of DSE, comprehensively presenting different facets of control and protection challenges arising in modern power systems. It is demonstrated how th...

This paper presents a two-stage framework for optimal Electric Vehicle (EV) charging/discharging strategy for DC Microgrid (MG) with Distributed Generators (DGs). A multi-objective optimisation task aimed at minimising system losses and EV battery degradation with Vehicle-to-Grid (V2G) peak shaving service has been realised. This coordinated EV int...

p>Maintaining power reserves in a photovoltaic (PV) system, i.e. operating at a curtailed power level, is a promising method towards grid support functions without energy storage. A major challenge in this approach is to monitor the maximum power (i.e. the available headroom) as it changes over time with the irradiance and temperature. This paper p...

Maintaining power reserves in a photovoltaic (PV) system, i.e. operating at a curtailed power level, is a promising method towards grid support functions without energy storage. A major challenge in this approach is to monitor the maximum power (i.e. the available headroom) as it changes over time with the irradiance and temperature. This paper pre...

This paper presents a fully distributed algorithm for the stochastic Volt/VAr control (VVC) problem in active distribution networks. Exact convexification of the VVC problem is achieved through the use of second-order cones on the continuous relaxation of the original optimization structure. The global optimum solution of the relaxed problem is obt...

A task force set up jointly by IEEE Power System Dynamic Performance (PSDP) Committee and CIGRE had addressed the issue of stability definition and classification in power systems from a fundamental viewpoint and had closely examined the practical ramifications. The relevant report published in 2004, primarily dealt with fairly slow, electromechani...

Recently, the Lambert W function has emerged as a valuable mathematical tool in photovoltaic (PV) modeling and other scientific fields. This increasing interest is because it can be used to reformulate the implicit equations of the single-diode PV model into explicit form. However, the computation of the Lambert W function itself is still not clear...

Trends support low voltage distribution networks will soon experience significant uptake of customer-owned low-carbon technology (LCT) devices especially rooftop photovoltaics (PVs) and small-scale energy storage (SSES) systems. This paradigm shift will introduce some significant challenges in modern distribution network planning and operations owi...

In this paper, the conventional Newton–Raphson fast decoupled (NRFD) power flow formulation is extended to allow the analysis of transmission and distribution systems (T&D) in a unified approach. The proposed extension associates the well-known computational efficiency of NRFD algorithms to the application of the complex per unit normalization (cpu...

Recently, the Lambert W function has emerged as a valuable mathematical tool in photovoltaic (PV) mod-eling and other scientific fields. This increasing interest is because it can be used to reformulate the implicit equations of the single-diode PV model into explicit form. However, the computation of the Lambert W function itself is still not clea...

This article proposes a power system state estimation (PSSE) capable of dealing with distribution and transmission networks. The proposed approach combines decoupled techniques, complex per unit (cpu) system, and a switching branch representation to meet the increasing complexity of state estimation issue when associated with the emerging electrica...

Example embodiments described herein are directed towards dynamic state estimation of an operating state of a generator in a power system. Such estimation is performed for an individual generator in realtime with improved accuracy and without the use of Global Position System (GPS) synchronization.

Large-scale photovoltaic (PV) integration to the network necessitates accurate modeling of PV system dynamics under solar irradiance changes and disturbances in the power system. Most of the available PV dynamic models in the literature are scope-specific, neglecting some control functions and employing simplifications. In this paper, a complete dy...

Dynamic estimation and control is a fast growing and widely researched field of study that lays the foundation for a new generation of technologies that can dynamically, adaptively and automatically stabilize power systems. This book provides a comprehensive introduction to research techniques for real-time estimation and control of power systems....

Owing to generation and demand mismatch, the frequency deviation and the rate of change of frequency (RoCoF) may become drastic at times in an islanded micro-grid. This is due to increased penetration of non-inertial renewable energy sources that brings down the system's resilience to any kind of disturbance. Therefore, efficient control algorithms...

This paper proposes a rigorous anomaly detection scheme, developed to spot power system operational changes which are inconsistent with the models used by operators. This novel technique relies on a state observer, with guaranteed estimation error convergence, suitable to be implemented in real time, and it has been developed to fully address this...

The hybrid power system state estimation problem requires computing the state of the power network using data from both legacy and phasor measurements. Recent research has shown that the normal equations approach in complex variables is computationally advantageous, particularly in the presence of phasor measurement values, and that its software im...

This paper proposes a decentralized method for estimation of dynamic states of a power system. The method remains robust to time-synchronization errors and high noiselevels in measurements. Robustness of the method has been achieved by incorporating internal angle in the dynamic model used for estimation and by decoupling the estimation process int...

Wide-area monitoring of power systems is important for system security and stability. It involves the detection and localization of power system disturbances. However, the oscillatory trends and noise in electrical measurements often mask disturbances, making wide-area monitoring a challenging task. This paper presents a wide-area monitoring method...

The inclusion of the governor droop and dead-band in dynamic models helps to reproduce the measured frequency response accurately and is a key aspect of model validation. Often, accurate and detailed turbine-governor information are not available for various units in an area control centre. The uncertainty in the droop also arise from the nonlinear...

Doubly-fed induction generators are suitable for systems having limited speed range as the overall control can be carried out by fractionally-rated converters. However, brushes and slip-rings used in these generators reduce system reliability and demand greater maintenance. Dual stator winding induction generator(DSWIG), being brushless, removes th...

This paper proposes a decentralized method for nonlinear control of oscillatory dynamics in power systems. The method is applicable for ensuring both transient stability as well as small-signal stability. The method uses an optimal control law which has been derived in the general framework of nonlinear control using normal forms. The model used to...

This paper proposes a decentralized derivative-free dynamic state estimation method in the context of a power system with unknown inputs, to address cases when system linearisation is cumbersome or impossible. The suggested algorithm tackles situations when several inputs, such as the excitation voltage, are characterized by uncertainty in terms of...

This paper has discussed transformer tap position estimation with continuous and discrete variables in the context of three phase distribution state estimation (SE). Ordinal optimization (OO) technique has been applied to estimate the transformer tap position for the first time in unbalanced three phase distribution network model. The results on 12...

This paper presents a new method to detect power system disturbances in a multivariate context, which is based on Fourth Order Moment (FOM) and multivariate analysis implemented as Singular Value Decomposition (SVD). The motivation for this development is that power systems are increasingly affected by various disturbances and there is a requiremen...

This work presents a probabilistic economic dispatch tool for energy management (EM) studies in the context of remote hybrid AC/DC microgrids (MGs). An EM approach is proposed to ensure a reliable power supply at the minimum cost of the hybrid MG operation. A comprehensive operational framework is presented, which considers topological features of...

This paper demonstrates a concept to detect bad data in state estimation when the leverage measurements are tampered with gross error. The concept is based on separating leverage measurements from non-leverage measurements by a technique called diagnostic robust generalized potential (DRGP), which also takes care of the masking or swamping effect,...

This paper presents a new approach in adaptive out-of-step (OOS) protection settings in power systems in real time. The proposed method uses extended equal area criterion (EEAC) to determine the critical clearing time and critical clearing angle of the system, which are vital information for the OOS protection setting calculation. The dynamic model...

Variable over voltage, excessive tap counts, and voltage regulator (VR) runaway condition are major operational challenges in distribution network while accommodating generation from photovoltaics (PVs). The conventional approach to achieve voltage control based on offline simulation for voltage set point calculation does not consider forecast erro...

This paper presents modeling and analysis of electrical oscillations in a wind farm system. The detailed modeling and modal analysis of a wind farm system are presented in this paper. The approach to modeling uses detailed representation of a wind turbine generator and collection system including high voltage direct-current (HVDC) power converter s...

This paper proposes a method for three-phase state estimation (SE) in power distribution network including onload tap changers (OLTC) for voltage control. The OLTC tap positions are essentially discrete variables from the SE point of view. Estimation of these variables in SE presents a formidable challenge. The proposed methodology combines discret...

This paper proposes a decentralized algorithm for real-time control of oscillatory dynamics in power systems. The algorithm integrates dynamic state estimation (DSE) with an extended linear quadratic regulator (ELQR) for optimal control. The control for one generation unit only requires measurements and parameters for that unit, and hence the contr...

This paper presents a generalized solution to the problem of optimal control of systems having an extra set of exogenous inputs besides control inputs. The solution is derived in the framework of linear quadratic control and it is termed ‘extended linear quadratic regulator (ELQR)’. The ELQR is applied for control of unstable or poorly damped oscil...

This study proposes a probabilistic multi-objective optimisation method for the operation of three-phase distribution networks incorporating active network management (ANM) schemes including coordinated voltage control and adaptive power factor control. The proposed probabilistic method incorporates detailed modelling of three-phase distribution ne...

State estimation has become an important task in modern energy/ distribution management systems. However, the state estimation is not very popular in modern unbalanced three-phase distribution systems. This paper proposes a method for three-phase state estimation with detailed three-phase modelling of system components including switches and star a...

This paper summarizes a set of six benchmark systems for the analysis and control of electromechanical oscillations in power systems recommended by the IEEE Task Force on Benchmark Systems for Stability Controls of the Power System Dynamic Performance Committee. The benchmark systems were chosen for their tutorial value and particular characteristi...

Large offshore wind farms are usually composed of several hundred individual wind turbines, each turbine having its own complex set of dynamics. The analysis of the dynamic interaction between wind turbine generators (WTG), interconnecting ac cables, and voltage-source converter (VSC)-based high voltage DC (HVDC) system is difficult because of the...

This paper proposes a novel implementation of a multiphase distribution network state estimator which employs industrial-grade modeling of power components and measurements. Unlike the classical voltage-based and current-based state estimators, this paper presents the implementation details of a constrained weighted least squares state calculation...

This paper presents a method for processing real-time data error in generalized state estimation (GSE). Attention is focused on the two main types of error: network topology errors and bad data on analog measurements. The proposed approach is able to handle both errors without making any previous assumption regarding the nature of those errors. The...

Variable over voltage, excessive tap counts, and voltage regulator (VR) textit{runaway} condition are major operational challenges in distribution network while accommodating generation from photovoltaics (PVs). The conventional approach to achieve voltage control based on offline simulation for voltage set point calculation does not consider forec...