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Due to the large-scale integration of renewable energy and inevitable disturbing events (including natural disasters and deliberate attacks), the invulnerability of power grids is facing a great challenge, thus the security criterion is demanded to upgrade from N − 1 to N − k. However, with the increasing of k and the expanding of network scale, resource consumption of network expansion shows an exponential explosion. Therefore, it is necessary to improve the invulnerability of power grids from a new perspective. In this paper, the definition of nodal N − k security criterion is proposed, which divides buses into different security levels based on realistic demand, and decouples the security analysis from the system level to individual nodes. A two-stage robust optimization model is established, cooperating with the nodal N − k security criterion, the load demand of critical buses could be guaranteed. Moreover, the proposed discrepant upgrade scheme is flexible and has strong generalization performance, where enhanced buses and security levels can be selected independently based on the preferences of decision-makers. The effectiveness and efficiency of the proposal have been demonstrated in 5 cases, i.e., the IEEE 9-bus, 24-bus, 57-bus, 118-bus systems and an actual test system in India. • The definition of nodal N − k security criterion is proposed. • A defender–attacker–defender (DAD) model cooperating with the criterion is established. • A gradual and progressive enhancement framework is provided. [ABSTRACT FROM AUTHOR]

The bid price of power generation in a country is of extreme importance due to its obvious impact on the industry although it is difficult to explore correlation among cost of a product in any industry with fluctuations of biding price of power. This is due to the fact that the fluctuations are nonlinear and extremely complex. Recent years have witnessed the study of this type of complex systems with powerful tool involving fractal methodology. This paper reports for the first time in Indian scenario a study on the fluctuation pattern of biding price of power in five different bid areas of India with a robust and rigorous technique based on chaos and fractal behavior. The exhaustive study reveals very interesting patterns of the fluctuation process, namely in all domains, the fluctuations are multifractal in time and degree of multifractality is quite different in different zones. The data is completely new and has serious implications on product cost of industry and ultimately on stock price indices. The paper includes possible future applications including predictability of next day price. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new approach to solve the hydro-thermal unit commitment problem using Simulated Annealing embedded Evolutionary Programming approach. The objective of this paper is to find the generation scheduling such that the total operating cost can be minimized, when subjected to a variety of constraints. A utility power system with 11 generating units in India demonstrates the effectiveness of the proposed approach; extensive studies have also been performed for different IEEE test systems consist of 25, 44 and 65 units. Numerical results are shown comparing the cost solutions and computation time obtained by conventional methods. [Copyright &y& Elsevier]

[Display omitted] • Indian electricity demand reduced by 11 % vis-à-vis 2019 during the lockdown. • Sectoral demand reduction—73 % industrial, remaining 27 % commercial. • Pan India lights-off event—hydropower provides the bulk of the flexibility (60 %). • The plant load factor of coal dropped to a record low of 35 % during phase-1. • Power sector emissions reduced by 16 % (86 MtCO2) compared to 2019. This paper aims to understand the responsiveness of the power sector during the lockdown due to the COVID-19 pandemic beginning from March 25, 2020 and analyses its impact on the demand, operation and supply of electricity in the Indian power system. The role of the C&I load share in reducing the electricity demand of the different states in India has been examined using multi-sectoral regression analysis. The impact of the pan India lights-off event on the short-term operational flexibility response of the power system has also been analysed using high-temporal resolution data. The results indicate that there has been a reduction of nearly 70 TWh of electricity demand during the lockdown period, an 11 % reduction compared to 2019. The top three states recording the highest reduction were Maharashtra, Gujarat and Tamil Nadu at 11 TWh, 10.6 TWh and 8.4 TWh, respectively. Regression analysis revealed that out of the total drop in load demand — 73 % is owed to the industrial sector, while the remaining 27 % is to the commercial sector. This demand drop also impacted the upstream electricity supply mix where 96 % of the reduction in supply was borne by the coal generating units, recording its lowest national plant load factor at 35 % with a 16 % reduction in overall CO 2 emission compared to the same period in 2019. In conclusion, a case study of Maharashtra has been used to analyse the impact of this reduction in electricity demand on the supply mix, hourly load profile and cost of supply under the different lockdown phases. [ABSTRACT FROM AUTHOR]

• Commendable of planning, coordination, execution, and resilience of power sector. • Grid security analysis in the pandemic. • The status of COVID-19, statistics of global electricity demand. • Analysis of main policies implemented by countries. Technology is advancing progressively at a very sharp rate in every phase of the commercial and economic issues, where energy plays a vital role in hi-tech enrichment. After continuous and multi directive research, human is efficient enough to put their steps on the peak of all imaginable pitches. But a human cannot fight against the environment in all instances. COVID-19, or Corona Virus, is such a type of environmental pandemic. Due to a large spread rate of COVID-19, the human society of the entire Globe is getting affected within a very small period. During its first and second wave, it collapses maximum countries health, economic structures along with the electrical sector. Many countries have enforced the 'lockdown' to their citizen for minimizing the community spread rate, which directly affects the energy sector. Standing in this scenario, this study focuses on the significant effect of COVID-19 on the energy sector of the Globe, especially in India. This paper also demonstrates that how several countries are trying to secure their power sector in this pandemic situation. [ABSTRACT FROM AUTHOR]

Abstract: This paper evaluates relative performance of the Electric Distribution Divisions (EDDs) of an Indian State, Uttarakhand for the period 2005–2008, through application of Data Envelopment Analysis (DEA). To improve the operational efficiency of EDDs, Uttarakhand Power Corporation Limited (UPCL) disintegrated several divisions into smaller ones over this period. However, microlevel examination revealed the ineffectiveness of this process during the period of analysis. Therefore, in the present work an alternative reorganization model for selecting the EDDs for disintegration and for selecting the optimum scale for disintegration is proposed based on the efficiency analysis of 2007. The model is verified by comparing the mean efficiency score of the EDDs derived using proposed model with that of existing ones. It is found that overall efficiency of proposed model is higher than the existing system. Reliability of the overall efficient EDDs is also examined to check the robustness of the CCR result for the same year. This study gives an assessment of UPCL to monitor and diagnose the changes in the efficiency of EDDs, so it will help regulators to formulate more effective policies on deregulation and disintegration and to determine the appropriate efficiency improvement measures when imposing yardstick competition on electric utilities. [Copyright &y& Elsevier]

Abstract: Hydro power plants are multipurpose projects, which are not only generating power but also responsible for the fulfillment of irrigation requirements of nearby zone. To harness the potential energy of released water Canal Head Power Houses (CHPHs) are also located at irrigation canals of the multipurpose projects. The present paper proposed a Novel Self Adaptive Inertia Weight Particle Swarm Optimization (NSAIW_PSO) approach to determine the optimal generation schedule of real operated cascaded hydroelectric system located at Narmada river in Madhya Pradesh, India. Here generation scheduling problem has been formulated in two cases. Case one considers natural inflows, evaporation losses and irrigation requirements assuming no generation through CHPHs. Whereas second case considers all above factors along with generation through CHPHs. Results show that in case two the amount of water discharge through all hydro power plants is less in comparison to case one to fulfill the same load demand, which shows the importance of CHPHs. [Copyright &y& Elsevier]

Abstract: Rural electrification is an integral component of poverty alleviation and rural growth of a nation. In India, electricity has not played effective role in the socio-economic growth of village. Gross Domestic Product (GDP) is increasing with 8% where as contribution of agriculture sector is 1.9%. Government of India has ambitious target of providing electricity to all villages by 2008 and all rural households by 2012. Steps are already initiated with Rural Electric Corporation, Rural Electricity Supply Technology mission, State Electricity Boards, Reforms in Power sector. An attempt has been made in this paper to assess the features of rural electrification in India and the feasibility of Photovoltaic Solar Home Systems (PV SHS). [Copyright &y& Elsevier]

• Small pumped hydro storage can replace batteries in autonomous microgrids. • Novel droop augmented control strategies for variable speed pumped hydro storage. • Pitch angle control of wind turbine is coordinated with the pumped hydro storage. • Dynamic droop coefficient results in minimum de-loading of wind turbine. • Pumped hydro storage has a forbidden region of operation, unlike batteries. An autonomous, sustainable microgrid with minimal operation and maintenance intervention would be a viable option to power the underprivileged remote communities in India. The microgrids supported by battery storage requires frequent maintenance and are prone to operational failures. So, the wind-powered agricultural pumping system is re-configured to form a hybrid microgrid with wind electric system (WES) and pico hydel energy storage (PHES) to meet the water and energy demands of the remote communities. As the frequency stability of autonomous microgrid is critical, a hierarchical frequency control framework is proposed in this paper. It has three different control aspects: firstly, novel droop augmented rapid power, and rapid speed control strategies are proposed for PHES. Secondly, the wind turbine is de-loaded by a dynamic droop integrated pitch angle controller to increase the inertial response of the system. Finally, a power management algorithm with suitable constraints is used to combine the control strategies of PHES and WES to derive the hierarchical frequency control framework. The effectiveness of the proposed framework is analysed through time-domain simulations using MATLAB/Simulink® by considering the change in wind speed, load, and the violation of water volume constraint. The proposed frequency control framework effectively managed the microgrid sources with suitable constraints and ensured minimal de-loading of the wind turbine. Furthermore, the framework also minimized the frequency nadir/peak and maintained the frequency within limits specified by the Indian Electricity Grid Code. [ABSTRACT FROM AUTHOR]

• Model order estimation methods are proposed for low frequency oscillations. • The methods detect the change in magnitude of eigenvalues of autocorrelation matrix. • A model order validation condition is proposed. • The proposed methodologies are tested on synthetic data and the field data. • The methods are compared with the existing techniques available for model order estimation. Estimation of low frequency oscillation modes is important for taking remedial actions to ensure the small signal stability of the power system. This paper proposes three approaches to estimate the model order of low frequency oscillations using ringdown data from Phasor Measurement Units. The first approach uses a sequential cumulative sum test on the eigenvalues of the autocorrelation matrix of the signal data to estimate the model order. The second approach estimates the model order based on the eigenvalue contribution in the trace of the autocorrelation matrix. The third algorithm uses sum of squares of the eigenvalues to estimate the model order. All the methods are compared to ascertain their efficacy in estimating the model. The algorithms are tested on oscillation data obtained for WSCC 9 bus system simulated on RTDS and the field data from a generating station in India. [ABSTRACT FROM AUTHOR]