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Summary In future power system operation, wide area monitoring applications will rely heavily on demand response (DR) because of its inherent characteristics mainly in ancillary services (AS). The DR is widely applied in power system; however, impact of DR loop with communication delay on dynamic performance of two‐area power system, mainly load frequency control (LFC), have not been reported by researchers. This paper presents the impact of DR control loop with communication delay in two‐area thermal power systems for improvement in frequency deviation profile. The optimal power sharing between supplementary and DR loop control is presented for different load variations. Further, efficacy of controller performance is also validated by introducing non‐linearities in generation in terms of generation rate constraint (GRC) and governor dead band (GDB). The simulations are performed with inclusion of DR for LFC control problem in (i) single‐area, (ii) two‐area thermal and (iii) thermal power system integrated with pumped hydropower system to improve the dynamic performance of system and hence minimize the frequency deviation. The controller in supplementary loop and DR loop is optimized using particle swarm optimization (PSO) technique. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, the quality of service (QoS) of communication infrastructure implemented in multi-area power system for load frequency control (LFC) application is assessed in smart grid environment. In study, network induced effects; time delay, packet loss, bandwidth, quantization and change in communication topology (CT) has been addressed to examine the system performance in closed loop. Uncertainty in time delay is approximated as deterministic and stochastic model. The network is modeled considering different network configurations, i.e. change in CT. The modeled communication network guarantees control relevant properties, i.e. stability.The decentralized controller and linear matrix inequality based linear quadratic regulator (LMI-LQR) is implemented to reduce the dynamic performance (mean square error of states variables) of power system as CT changes. Simulation results suggest that proposed scheme of networked control is superior with respect to other design method available in literature and thus robust to communication imperfections. Index Terms-Bandwidth, Communication topology, LFC, LMI-LQR, Smart Gridfuture smart grid, it is expected that PMU is installed extensively across the power grid. Smart grid (SG) incorporates a two way digital communication technology which integrates the communication technology and intelligent computer processing technology into a large scale power system for quick monitoring, control, self-healing, selforganizing and robustness for physical system, so that consumer may be benefitted [6][7]. SGs require reliable communication systems. It is well known that due to high speed open communication infrastructure, i.e. wireless networks, are unreliable because of time delay, packet loss and the communication failure. Further a comprehensive review on SG potential application and communication requirement is presented in [8].Communication technologies and their impact on power system operation need a closer study to implement the control strategy. The power systems rely on control algorithms having information exchanged via communication networks. Any network effects jeopardize failure rate of control itself. Recently, researchers have reported coupling of power system and communication networks as discrete-event triggering systems for LFC for multi area power system with communication delays [9].In real-time monitoring of smart grid operation, it is essential to exploit the high speed of throughput. The need of real-time information and strict latency requirements for bulk amounts of data has been proposed in [10]. The strict latency of most of the application of smart grid lies between 100 ms to 5 sec [11]. Further the detail description of latency requirements for power system operation is given in [1]. The time duration of transient stability is less than 100 ms, small signal stability is less than 1 sec, voltage stability between 1-5 sec and grid disturbances in range of few minutes. The communication delay on a network includes the transmission delay, propagation delay, q...

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Bidirectional dc to dc converter is used as a key device for interfacing the storage devices between source and load in renewable energy system for continuous flow of power because the output of the renewable energy system fluctuates due to change in weather conditions. In electric vehicles also, bidirectional converter is used between energy source and motor for power supply from battery to motor. Thus, bidirectional dc to dc converters are getting more and more attention in academic research and in industrial applications. Bidirectional dc to dc converters work in both buck and boost mode and can manage the flow of power in both the direction between two dc sources and load by using specific switching scheme and phase shifted control strategy and hence generated excess energy can be stored in batteries/super capacitors. Therefore, the basic knowledge and classification of bidirectional dc to dc converters on the basis of galvanic isolation, the comparison between their voltage conversion ratio and output current ripple along with various topologies researched in recent years are presented in this paper. Finally, zero current and zero voltage soft switching schemes and phase shifted controlling techniques are also highlighted.

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