Optimizing static interphase power controllers (SIPC) placement: A comprehensive multi-objective strategy for enhanced performance of the electric transmission networks

Deregulation of power sector leads to overloading of transmission lines due to high demand of consumers. To fulfill demand of power, generation companies produce more output, but transmission lines are the conventional ones and they get congested as they carry more power than its capacity. To reduce congestion FACTS devices are used, which control power flow and reduce losses, thus reduces congestion. In this paper Thyristor Controlled Series Compensators (TCSC) has been used, TCSC is a series FACTS device which changes reactance of transmission line and thus controls power flow through that line, leads to reducing congestion. Appropriate location of TCSC has been found out by various indices. TCSC placement is done at these locations under base case and varying load condition and improvement in transmission line loading is observed. Work is carried out on IEEE 30 bus test system.

Incorporating Flexible AC Transmission Systems (FACTS) devices into modern power systems is a crucial field of study, mainly due to the growing adoption of renewable energy sources. This paper thoroughly examines the role and efficacy of FACTS devices in improving power quality and maintaining stability in both conventional power systems and those that heavily rely on renewable energy sources. At first, the central aspect of the review centers on different FACTS devices, including Static VAR Compensators (SVC), Thyristor Controlled Series Capacitors (TCSC), Unified Power Flow Controllers (UPFC), and distributed power flow controllers (DPFC). A comprehensive analysis of each device's operational principles, benefits, and constraints is provided. The paper assesses the efficacy of these devices in addressing the challenges associated with integrating renewable energy. These functions encompass their involvement in maintaining voltage levels, stabilizing frequency, controlling power flow, and enhancing the power system's ability to respond to sudden changes. This paper compares various FACTS devices in different scenarios to emphasize their efficacy in specific contexts. Furthermore, the paper outlines the emerging difficulties in power systems caused by the incorporation of fluctuating renewable energy sources, such as wind and solar power. The challenges encompass voltage fluctuations, frequency instability, and power flow control issues. Advanced solutions are required to maintain power quality and ensure grid stability due to the variability and unpredictability of renewable energy sources. Furthermore, the paper examines the possibilities and future advancements in FACTS technology. The article explores the potential of utilizing power electronics, control strategies, and artificial intelligence integration to improve the performance and effectiveness of FACTS devices. To summarise, the review emphasizes the crucial importance of FACTS devices in modern power systems, especially concerning the growing integration of renewable energy sources. It emphasizes that the strategic deployment of these devices is essential for guaranteeing power quality and stability, enabling a more seamless shift towards sustainable and resilient power systems.

The rapid increase in the power generation from various emerging wind and solar projects are proving to be highly beneficial and eco-friendly. But adding a new renewable resource onto an existing transmission network has become a challenge. The existing transmission network should be in a position to accept the newly generated power, when a renewable source is integrated onto it. This paper explains the simulated results of various Series Compensated FACTS devices by which the enhancement could be carried out there by considering the Installation of new transmission lines as a final resort for integrating the renewable sources. An assessment carried out in this sequence to enhance the power transfer capacity to facilitate the renewable penetration will prove to be an efficient approach. The various ways for enhancing the power transfer capacity of a transmission network to enhance the power flow is totally a different concept. The application discussed in this paper is yet another concept of enhancing the power transfer capability of a transmission network by the various techniques mentioned above strictly for integrating renewable resources. Initially couple of Real Time Scenario were discussed where Series FACTS Devices had been installed on the Lines only to Increase the Power Transfer Capability for accommodating more Renewable Energy Resources. Apart from this, the main objective of this paper is to present the simulation results of a Standard 5 Bus Test System. The Series Connected FACTS devices are connected for increasing the Power transfer capability of the lines that would give more spacing for the Renewable Energy Devices like PV Solar and Wind to be integrated.

Stochastic flexible transmission operation for coordinated integration of plug-in electric vehicles and renewable energy sources

Series FACTS devices have been successfully used for many years in order to enhance the stability and loadability of high voltage transmission networks. The principle is to compensate the inductive voltage drop in the line by an inserted capacitive voltage or in other words to reduce the effective reactance of the transmission line to enhance available transfer capability (ATC) in the network. ATC accurately reflects the physical realities of the transmission network, all system conditions, uses, and limits in a consistent manner. It depends on other parameters namely total transfer capability (TTC), capacity benefit margin (CBM), transmission reliability margin (TRM), and existing transmission commitments (ETC) that are described in this study thoroughly. This paper investigates the optimized use of FACTS devices and mainly thyristor controlled series capacitor (TCSC) to improve ATC and maximize total transfer capability generally defined as the maximum power transfer transaction between a specific power-seller and a power-buyer in a two area designed power system. The case study has been implemented on a 13-bus multi-machine test system using PowerWorld Simulator version 12.0. Furthermore, static linear analysis methods have been taken into account in calculating ATC and the impact on various factors has been defined clearly.

Looking for optimal number and placement of FACTS devices to manage the transmission congestion

Determining maximum loading margins is an important issue in power system operation, as system operators must take proper preventive actions to avoid stability problem. This paper presents a study of parallel FACTS devices and series FACTS devices on steady-state voltage and power stability. Their steady state modeling and effects on power system performance have been studied. It also studies static stability improvement of the power system and hence power flow improvement in the network. Effects of FACTS on system loadability have been discussed and presented here. A method based on the concept of maximum loading point index has been used to compare FACTS devices. The study has been carried out on the IEEE 14 bus test system. The line power transfer capability and loadability of the system and therefore, the stability of the system is increased. It has also been observed that for the improvement of these parameters, the parallel FACTS devices are more adequate than the series FACTS devices.

Determining maximum loading margins is an important issue in power system operation, as system operators must take proper preventive actions to avoid stability problem. This paper presents a study of parallel FACTS devices and series FACTS devices on steady-state voltage and power stability. Their steady state modeling and effects on power system performance have been studied. It also studies static stability improvement of the power system and hence power flow improvement in the network. Effects of FACTS on system loadability have been discussed and presented here. A method based on the concept of maximum loading point index has been used to compare FACTS devices. The study has been carried out on the IEEE 14 bus test system. The line power transfer capability and loadability of the system and therefore, the stability of the system is increased. It has also been observed that for the improvement of these parameters, the parallel FACTS devices are more adequate than the series FACTS devices.

Conventional phase‐shifting transformers (PST) have been utilized for power flow control in transmission networks for many years. Compared to the slow reacting PSTs, recently trending unified power flow controllers (UPFC) enable much faster power flow control. This paper introduces a decentralized power flow control scheme for power flow controllers (PFCs) without the need for communication between the PFCs. For each PFC, an influence area is defined. The line loading of the transmission lines in this influence area is monitored in real‐time operation and if there is an overloading of a line, a feedback control scheme is used to mitigate the overloading of the line. As the power flow control of UPFC is dependent of the network topology and the UPFC converter limit, additional control measures are introduced to circumvent potential critical scenarios. Supplementary control measures are also developed to increase the robustness of control scheme for the simultaneous operation of UPFC with slow reacting PST. Using RMS simulation in DIgSILENT PowerFactory, the developed control method is validated in the IEEE 68‐Bus NETS/NYPS test bench network. The method is also validated for UPFCs with overlapping influence areas and the combination of fast acting UPFCs and slow acting PST devices.

Severe weather conditions are low-probability, high-impact events that affect grid operations. The majority of power outages are caused by severe weather conditions. Grid resiliency to weather events can be enhanced by decreasing the reliance on its affected sections. One way to do this is to reduce the power flow through lines vulnerable to severe weather. If a line is disconnected, its initial power flow is distributed through the neighbor lines, which may cause congestion in the grid. FACTS devices can be used to control the power flow of lines that have a higher chance of power outages. Most previous works do not consider weather events in power flow control. In this work, a linearized optimal power flow (OPF)–based algorithm is developed to minimize the real power flow of vulnerable lines considering the thermal limits of lines to prevent infeasible solutions; the simulation is fast, making it suitable for large-scale systems. The proposed optimization problem is presented as a mixed-integer linear program (MILP), making it capable of using short-term load forecasting due to its high solution speed. The proposed optimization problem considers multiple lines with different outage probabilities and the uncertainties of the weather forecast. Moreover, it estimates the power reduction in vulnerable lines due to changes in the series FACTS devices. The performance of the proposed optimization problem is tested on IEEE 14-, 30-, and 118-bus systems for several scenarios. The results are validated with the AC power flow results from MATPOWER.

Integration of distributed renewable energy sources in Israel: Transmission congestion challenges and policy recommendations

The electrical energy produced at the generating station is conveyed to the consumers through a network of transmission and distribution systems. It is often difficult to draw a line between the transmission and distribution systems of a large power system. It is impossible to distinguish the two merely by their voltage because what was considered as a high voltage because what was considered as a high voltage a few years ago is now considered as a low voltage. In general, distribution system is that part of power system which distributes power to the consumers for utilization. Analysis of radial distribution systems with embedded series FACTS devices is facilitated by a formulation of power flow equations with bus voltage magnitudes and line flows as independent variables The line flow-based (LFB) formulation is shown to provide easy implementation with multiple series FACTS devices in the system and enable direct evaluation of the FACTS device ratings. Keywords: FACTS, LFB, Radial distribution system DOI : 10.7176/NCS/10-01 Publication date :July 31 st 2019

The increasing extension of the European power system to the east and the large offshore wind power injections within the next years demand additional measures to improve the damping of inter-area oscillations. Multifunctional FACTS devices can provide an interesting contribution to the unavoidable reinforcement of the power system. A systematic examination of the damping potential of shunt and series FACTS devices in the transmission system is presented with the evaluation of new modeshapes indicating the sensitivity of voltages and currents to inter-area oscillations. By means of an exemplary scenario, the demanded quantity, rating and siting of shunt or series FACTS devices are determined and results of various examinations are summarized to general statements regarding the benefit of multifunctional FACTS devices in the UCTE.

Deregulation and privatization are posing new challenges to high voltage transmission and distributions systems. System components are loaded up to their thermal limits, and power trading with fast varying load patterns is leading to an increasing congestion. In addition to this, the dramatic global climate developments call for changes in the way electricity is supplied. Innovative solutions with HVDC (High Voltage Direct Current) and FACTS (Flexible AC Transmission Systems) have the potential to cope with the big challenges of the evolving power markets. New power electronic technologies, using the PEBB (Power Electronic Building Blocks) concept with self-commutated modular multilevel converters (MMC) provide advanced technical features for control of voltage and power flow, the capability to supply weak or even passive networks as well as reduction in space requirements. The technology, named as HVDC PLUS and SVC PLUS <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> , is dedicated for the intensified integration of Renewable Energy Sources (RES), e.g. large wind farms. The tasks are transmission, when DC cables are applied, as well as power quality for Grid Code compliance, especially when AC cables are used [1-6].

Power flow control in double circuit transmission lines is crucial for maintaining system stability and ensuring optimal utilization of resources. This paper proposes a novel approach using a Five Level Unified Power Flow Controller (UPFC) with a Grey Wolf Optimizer (GWO) tuned Proportional-Integral (PI) controller. The Five Level UPFC acts as a flexible and efficient solution, facilitating the concurrent regulation of both active and reactive power flow in transmission lines. By applying the GWO algorithm, the aim is to improve the performance of the UPFC control system through the optimization of the PI controller's parameters. By imitating the natural hunting behaviour of grey wolves, the GWO algorithm achieves exceptional convergence and solution accuracy. The suggested control scheme is implemented and tested on a double circuit transmission line system. The system's effectiveness is evaluated under various operating conditions and compared against alternative control approaches. The findings establish the efficacy of the Five Level UPFC with a GWO-optimized PI controller in effectively regulating power flow and enhancing overall system stability. Furthermore, the proposed approach exhibits excellent robustness against parameter variations, load fluctuations, and system disturbances. The GWO optimization technique ensures optimal tuning of the PI controller, this leads to decreased power losses, enhanced voltage profile, and improved system reliability. Overall, the application of the Five Level UPFC with GWO-tuned PI controller provides an efficient and reliable solution for power flow control in double circuit transmission lines. The suggested method can make a substantial contribution to enhancing the operational efficiency of power systems, this enables the seamless integration of renewable energy sources and the progression of smart grid infrastructures. The circuit is simulated using the MATLAB/SIMULINK software. And the following results from the simulation are presented below