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Aimed at reducing the redundancy of parameters for the power system stabilizer (PSS) and static var compensator (SVC), this paper proposes a method for coordinated control and optimization based on the neighborhood rough set and improved whale optimization algorithm (NRS-IWOA). The neighborhood rough set (NRS) is first utilized to simplify the redundant parameters of the controller to improve efficiency. Then, the methods of the Sobol sequence initialization population, nonlinear convergence factor, adaptive weight strategy, and random differential mutation strategy are introduced to improve the traditional whale optimization algorithm (WOA) algorithm. Finally, the improved whale optimization algorithm (IWOA) is utilized to optimize the remaining controller parameters. The simulation results show that the optimization parameters were reduced from 12 and 18 to 3 and 4 in the single-machine infinity bus system and dual-machine power system, and the optimization time was reduced by 74.5% and 42.8%, respectively. In addition, the proposed NRS-IWOA method exhibits more significant advantages in optimizing parameters and improving stability than other algorithms. [ABSTRACT FROM AUTHOR]

This paper proposes a novel methodology to improve stability in a transmission system under critical conditions of operation when additional loads that take the system to the verge of stability are placed in weak bus bars according to the fast voltage stability index (FVSI). This paper employs the Newton–Raphson method to calculate power flows accurately and, based on that information, correctly calculate the FVSI for every transmission line. First, the weakest transmission line is identified by considering N − 1 contingencies for the disconnection of transmission lines, and then all weak nodes associated with this transmission line are identified. Following this, critical scenarios generated by stochastically placed loads that will take the system to the verge of instability will be placed on the identified weak nodes. Then, the methodology will optimally size and place a single static VAR compensator SVC in the system to take the transmission system to the conditions before the additional loads are connected. Finally, the methodology will be validated by testing the system for critical contingencies when any transmission line associated with the weak nodes is disconnected. As a result, this paper's methodology found a single SVC that will improve the system's stability and voltage profiles to similar values when the additional loads are not connected and even before contingencies occur. The methodology is validated on three transmission systems: IEEE 14, 30, and 118 bus bars. [ABSTRACT FROM AUTHOR]

In the electrical networks of mining enterprises, power supply to powerful loads, e.g., mining excavators, is carried out using cantilever lines. During operation of a cyclic, powerful, sharply variable load and energy recovery, deviations and voltage fluctuations are observed. A method to reduce voltage fluctuations in this network is considered using a static VAr compensators, the operating algorithm of which involves control over the capacitive/inductive current in the supply line in proportion to the active component of the load current. The proportionality coefficient between the reactive current of a line and the active load current is taken to be equal to the ratio of active and inductive resistance of the supply line. The complex resistance of the supply electrical network is assumed to be known or identified during operation. The equations are given to calculate currents in the power supply system for different modes. The electrical power processes during operation of a thyristor–reactor VAr compensator with a special controller have been carried simulated. [ABSTRACT FROM AUTHOR]

Flexible alternating current transmission systems (FACTSs) have been widely incorporated in electric power systems in order to control system parameters. This paper proposes the modeling of four FACTS devices, using the Branch Flow Model (BF) as an optimization problem to reduce the complexity of the Newton–Raphson (NR) load flow code with FACTS devices. The devices are represented as variable impedances, as a function of a firing angle, and as voltage source converters (VSCs) located on the buses and transmission lines. This proposed model solves the problem associated with the selection of appropriate initial conditions of the parameters of each device that guarantee convergence. The model is validated by evaluating its percentage deviation with respect to the NR method, using the standard test systems, IEEE 5-bus, IEEE 14-bus, IEEE 30-bus, and IEEE 57-bus systems. [ABSTRACT FROM AUTHOR]

This paper presents new methodologies for modeling static VAr compensators (SVCs) in the power flow problem. The proposed formulations utilize sigmoid functions to model the control equations that describe the steady-state behavior of SVCs. The first methodology introduces reactive power injection as a new state variable, while the second methodology utilizes the thyristor firing angle. These steady-state SVC methodologies were applied to the power flow problem using the full Newton formulation, which incorporates the control equations into the system of nonlinear equations. One of the main contributions of these proposed methodologies is that they eliminate the need for alternating adjustments concerning the operational limits of the SVC during the iterative power flow process. The implementation of a power flow program was tested on both small-scale tutorial systems and the medium-scale IEEE Nordic system. The presented results validate and demonstrate the effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

The appeal of Electric Vehicles (EVs) is steadily growing, driven by the numerous advantages they offer to both owners and the environment. However, this surge in EV adoption places an increasing demand on the power system network for electric charging. The consequential strain on the power system may lead to instability and potential contingencies within the network. To mitigate these challenges, this paper recommends the installation of Flexible AC Transmission System (FACTS) devices. Specifically, two types of FACTS devices, Static Var Compensator (SVC) and Thyristor-Controlled Series Capacitor (TCSC), are employed to enhance the stability and loading conditions of the power system network. The study focuses on an IEEE 39 bus system network chosen for the installation of Electric Vehicle Charging Stations (EVCS). The objective is to assess the maximum loading factor of each bus within the network. This paper introduces a methodology for determining the optimal locations for both EVCS and FACTS devices. Notably, a Particle Swarm Optimization (PSO) algorithm is employed to optimize the size of FACTS devices and associated installation costs, ensuring an efficient and cost-effective enhancement to the power system's stability and loading conditions.

This paper presents a method for stability improvement for the standard IEEE14 bus system by using Static VAR Compensators (SVCs). The SVC, a shunt Flexible AC Transmission System (FACTS) device, can effectively improve the voltage profile at several buses in the system, thereby improving the overall system stability. In this system, some loads are increased by either (1) switching on a sudden load change parallel to the original loads in the system or (2) scaling the original load by a large factor. The resulting system is an overloaded version of the IEEE14 bus system. A Phasor Measurement Unit (PMU) is installed at each bus in the system to measure accurately the voltage magnitude, the frequency, and the phase angle values in every bus location. This study compares the voltage magnitude and frequency for four cases. In each case, the SVC is installed in a different location in the system. The voltage magnitude values at each bus are recorded before switching on the additional loads, during the period when the additional loads are switched on, and after switching off the additional loads. Each case has been studied separately, and the SVC parameters have been adjusted separately for each case to provide a suitable voltage compensation, while maintaining stable operation. The incorporation of SVCs has shown improvements and advantages in the system's voltage and transient stability. In addition, the overshoot and the settling time of the voltage magnitude and frequency have been recorded to study further the stability of these signals. The best results for voltage magnitude compensation have been shown to occur at the bus where the SVC is installed. The best results in terms of improvement in voltage magnitude have been achieved when the SVC has been installed at bus 3, while the best results in terms of improvements in overshoot for voltage and frequency have been obtained when the SVC has been installed at bus 6. [ABSTRACT FROM AUTHOR]

This study addresses the challenges associated with integrating photovoltaic (PV) systems into the Western Algerian power grid, primarily focusing on mitigating frequency fluctuations induced by variable electrical load profiles. These fluctuations can have adverse effects on power quality and grid stability. To address this challenge, the study introduces the benefits of frequency stability analysis and Optimal Power Flow (OPF) control within distributed and adaptable power networks. The primary goal is to enhance the integration of PV systems by ensuring the dynamic stability of the network, optimizing solar energy utilization through the Maximum Power Point Tracking (MPPT) technique, and employing var compensation methods. These strategies are designed to facilitate reliable and economically viable PV integration into the power grid, particularly in the SAIDA-NAAMA region. Through the implementation of OPF control, var compensation techniques, and PV integration, this research achieves a notable reduction in power losses, ranging from 10% to 25% within a single day. Furthermore, the utilization of reactive power control, employing NAAMA's Static Var Compensator (SVC) for the transmission network, along with localized compensatory measures for the distribution network, effectively maintains voltage levels within acceptable parameters. These combined efforts provide critical support for the advancement of PV integration, the transition towards Variable Renewable Energy (VRE) sources, and the promotion of sustainable power generation practices within the region. [ABSTRACT FROM AUTHOR]

This paper proposes a novel methodology to improve stability in a transmission system under critical conditions of operation when additional loads that take the system to the verge of stability are placed in weak bus bars according to the fast voltage stability index (FVSI). This paper employs the Newton–Raphson method to calculate power flows accurately and, based on that information, correctly calculate the FVSI for every transmission line. First, the weakest transmission line is identified by considering N−1 contingencies for the disconnection of transmission lines, and then all weak nodes associated with this transmission line are identified. Following this, critical scenarios generated by stochastically placed loads that will take the system to the verge of instability will be placed on the identified weak nodes. Then, the methodology will optimally size and place a single static VAR compensator SVC in the system to take the transmission system to the conditions before the additional loads are connected. Finally, the methodology will be validated by testing the system for critical contingencies when any transmission line associated with the weak nodes is disconnected. As a result, this paper’s methodology found a single SVC that will improve the system’s stability and voltage profiles to similar values when the additional loads are not connected and even before contingencies occur. The methodology is validated on three transmission systems: IEEE 14, 30, and 118 bus bars.

The Thyristor Controlled Reactor (TCR), an operative reactive power device, is controlled non-linearly in its inductive operational mode, resulting in injection of odd current harmonics. This introduces challenges regarding power quality, which necessitates conditioning of the device. In this study, the development of a continuously and linearly controlled compensating susceptance, constructed from a TCR equipped with harmonic suppression and absorption features, is presented. The series suppression circuitry incorporated within the design consists of a series RLC circuit, resonating at the frequency of the AC source. Simultaneously, the shunt absorption circuitry is specifically designed to eliminate the third and fifth harmonic current components produced by the TCR. This innovative arrangement substantially minimizes the odd harmonics generated by the TCR. In addition, an advanced current controller has been introduced, allowing the reactive current of the proposed susceptance to be linearly controlled in both inductive and capacitive modes. The proposed susceptance was designed and simulated on PSpice, utilizing a 50Hz, 220V AC source. Simulation results demonstrate that the susceptance current reaches its steady-state value within approximately 100ms. Furthermore, the susceptance current in the steady-state region is almost completely devoid of harmonics. Notably, the proposed susceptance displays remarkable linearity during its response to reactive current demands across both inductive and capacitive operational modes. This research provides a significant step forward in addressing the challenges associated with TCR power quality. [ABSTRACT FROM AUTHOR]

Summary: This paper utilizes a static var compensator in coordination with an intelligent online controller, to enhance the oscillation damping of the power system at various operating conditions and communication delays. For system identification, a linear identifier is used that ensures a low computational burden and facilitates its real‐time implementation. This identifier accurately estimates the system's local linear model using local measurements and continuously updates its parameters in real time to account for system's changing operational states. The learning rate of the identifier is also adaptively adjusted such that the stability of the learning algorithm and optimal speed of convergence are guaranteed. The location of the controller is selected based upon the controllability and bus voltage participation factors, and an effective feedback signal is obtained using the observability. An empirical expression has also been proposed to offset the effects of communication time delays caused due to use of wide‐area signals. Time‐domain simulations are performed on single‐ and multi‐machine power systems to check the efficacy of the proposed intelligent controller. The performance of the controller is compared with the residue‐based conventional controller and also with the recently proposed wide‐area damping controller. [ABSTRACT FROM AUTHOR]

This paper presents multi-objective congestion management of transmission lines using time-of-use (TOU) based demand response (DR) program and static var compensator (SVC). Congestion of transmission lines is managed, while system parameters such as generation fuel cost and active power losses are reduced, in addition to enhancement of bus voltages. The SVC was modeled as a reactive power injector, while the TOU–based DR was modeled using the price elasticity of demand for responsive loads. Particle swarm optimization was used for the optimal placement and sizing of the SVCs, considering the rolled-out DR program in MATLAB/MATPOWER. The DR program was first tested separately on the IEEE-30 bus test system to show its effects on the afore-mentioned system parameters. Subsequently, the DR program was combined with the SVC, and again tested on the IEEE-30 bus test system. The results showed a significant improvement of 1.414% on the voltage profile, 44.65% reduction on the generation fuel cost, and much significant 71.13% reduction on the system losses with the proposed method, compared with the Base Case Scenario (the Peak Period) where there was congestion. This shows the effectiveness of the proposed hybridized DR-SVC method in congestion management of transmission lines.

Supplementary damping controller (SDC) for static var compensator (SVC) can be used to damp interarea low-frequency oscillations, but the influence of signal transmission delay on damping performance is generally neglected in the previous research. Because the delay may deteriorate damping performance or even cause instability for power system, this work intensively investigates the influence of signal transmission delay on input signal selection and parameter setting in SDC design. A novel evaluation method based on delay-dependent stability criterion and model order reduction is proposed to obtain the tradeoff between damping performance and delay margin for the SDC to be designed. Delay margin, determined by the proposed method, is taken as a critical index to evaluate the delay influence on SDC design. Case studies are carried out on two-area four-generator power system. Results show that for input signals with higher mode observability by residue method, such as current magnitude and active power of transmission line, delay margin decreases with the increase of SDC gain or delay variation ratio, which indicates that appropriately setting the gain can ensure SDC with better damping performance and larger delay margin.

An electrical power system (EPS) is subject to unexpected events that might cause the outage of elements such as transformers, generators, and transmission lines. For this reason, the EPS should be able to withstand the failure of one of these elements without changing its operational characteristics; this operativity functionality is called N − 1 contingency. This paper proposes a methodology for the optimal location and sizing of a parallel static Var compensator (SVC) in an EPS to reestablish the stability conditions of the system before N − 1 contingencies take place. The system's stability is analyzed using the fast voltage stability index (FVSI) criterion, and the optimal SVC is determined by also considering the lowest possible cost. This research considers N − 1 contingencies involving the disconnection of transmission lines. Then, the methodology analyzes every scenario in which a transmission line is disconnected. For every one of them, the algorithm finds the weakest transmission line by comparing FVSI values (the higher the FVSI, the closer the transmission line is to instability); afterward, when the weakest line is selected, by brute force, an SVC with values of 5 Mvar to 100 Mvars in steps of 5 Mvar is applied to the sending bus bar of this transmission line. Then, the SVC value capable of reestablishing each line's FVSI to its pre-contingency value while also reestablishing each bus-bar's voltage profile and having the lowest cost is selected as the optimal solution. The proposed methodology was tested on IEEE 14, 30, and 118 bus bars as case studies and was capable of reestablishing the FVSI in each contingency to its value prior to the outage, which indicates that the algorithm performs with 100% accuracy. Additionally, voltage profiles were also reestablished to their pre-contingency values, and in some cases, they were even higher than the original values. Finally, these results were achieved with a single solution for a unique SVC located in one bus bar that is capable of reestablishing operational conditions under all possible contingency scenarios. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method to find the optimal location of the shunt connected Flexible AC Transmission Systems (FACTS) such as Static Var Compensator (SVC) or Static Synchronous Compensator (STATCOM) to the power system for regulating voltage levels of all buses. Three indices include Voltage Drop Index (VDI), Total Voltage Drop Index (TVDI), and Total Voltage Drop of Network Index (TVDNI) are presented to find the location of the SVC. Also, to minimize the solution space, a ranking list will be established. For the case studies, the IEEE 14-bus test system is selected, and an SVC is located in the system. Simulations are done in two cases: network loads increase with constant coefficient and randomly. According to simulation results in both cases, the proposed method can identify the optimal placement of SVC, and the voltage drop due to increasing the load will be compensated. For the IEEE 14-bus test system, the optimal location of the SVC is bus 9. Variable loads are considered for 24 h, and SVC is installed at bus 9 to validate the introduced method. Results show the voltage level for all buses is compensated so that the voltage levels are higher than the minimum voltage level, i.e. 95%. [ABSTRACT FROM AUTHOR]

Flexible alternating current transmission systems (FACTSs) have been widely incorporated in electric power systems in order to control system parameters. This paper proposes the modeling of four FACTS devices, using the Branch Flow Model (BF) as an optimization problem to reduce the complexity of the Newton–Raphson (NR) load flow code with FACTS devices. The devices are represented as variable impedances, as a function of a firing angle, and as voltage source converters (VSCs) located on the buses and transmission lines. This proposed model solves the problem associated with the selection of appropriate initial conditions of the parameters of each device that guarantee convergence. The model is validated by evaluating its percentage deviation with respect to the NR method, using the standard test systems, IEEE 5-bus, IEEE 14-bus, IEEE 30-bus, and IEEE 57-bus systems.

Voltage and reactive power become one of the most critical aspects to monitor and sustain at an appropriate level in vast alternative current networks to ensure good functionality, load satisfaction, network integrity, and service quality. The network's spending should be obtained by calculating the load flow or applying more controllable variables to it, defined as the optimization power flow. In this vein, this paper focuses on improving the network's voltage profile, reactive power generation, and losses. The study begins with load flow estimation in various situations using the Newton–Raphson process, followed by an optimization capacity calculation using the simplified Reduced Gradient power flow method. For each system, four cases are simulated, one with and one without the SVC (Static Var Compensator) device, which is positioned in an ideal position on the IEEE 57 bus network. The confirmation of the data is carried out using the MATLAB program. A distinction is made between the two approaches based on the SVC device's position and its reactive power generation into the network. The simulation results indicate that the generalized Reduced Gradient optimization approach (GRG-OPF) offers reasonable efficiency, quick iteration in the simulation results, the best power budget with minimal active/reactive losses and the best voltage profile specifically in the case where SVC reactive power is taken as a variant into the GRG-OPF method. [ABSTRACT FROM AUTHOR]

The strategic intent of the African Union is to develop a "Smart Integrated African Electric Power Super Grid" driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa's sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Thus, the application of innovative technologies such as HVDC links can stabilize weak power systems. It is established that HVDC delivery systems reduce losses in long transmission lines transporting bulk power compared with high-voltage alternating current (HVAC) transmission lines for power wheeling. This paper evaluates the parallel operation of the Cahora Bassa 1414 km bipolar HVDC link and a weak parallel 400/330 kV alternating current (AC) link. It demonstrates the use of FACTS controllers to enhance the technical performance of an existing network, such as voltage control, and technical loss reduction. It combines an HVDC line commutated converter (LCC) and HVAC transmission lines, in hybrid notation to increase the voltage stability of the system by controlling the reactive power with a Static Var Compensator (SVC). These modern tools can increase the transmission power controllability and stability of the power network. In this study, HVDC–LCC was used with a setpoint of 1000 MW in conjunction with the 850 MVAr SVC. The results show that the technical losses were reduced by 0.24% from 84.32 MW to 60.32 MW as Apollo 275 kV SVC was utilized for voltage control. The network analysis was performed using DIgSILENT PowerFactory software that is manufactured by DIgSILENT GmbH at Gomaringen, Germany [ABSTRACT FROM AUTHOR]

A constant worldwide growing load stress over a power system compelled the practice of a reactive power injection to ensure an efficient power network. For this purpose, multiple technologies exist in the knowledge market out of which this paper emphasizes the usage of the flexible alternating current transmission system (FACTS) and presents a comparative study of the static var compensator (SVC) with the static synchronous compensator (STATCOM), inducted in a real electric substation. The aim is to improve the power factor (PF) and power quality and to encounter reliably extreme conditions. A 220 kV electric substation was opted for the analysis, and both the static and dynamic conditions were observed with the help of a power system analysis tool termed PowerFactory-DIgSILENT. Multiple aspects were investigated via software simulations to assess the performance of the aforementioned FACTS devices, such as the voltage profile evaluation via the load flow analysis method (LFA), the harmonic response via the power quality and harmonic analysis tool, and the short-circuit response via the RMS simulation tool. The outcomes were verified and compared with permissible values included in the universal standards, such as IEC and IEEE. The superiority of the STATCOM over the SVC was proven in light of the simulative results. [ABSTRACT FROM AUTHOR]

In order to improve the Power Quality (PQ) of traction power supply system and reduce the power rating and operation cost of compensator, a Static VAR Compensator (SVC) integrated Railway Power Conditioner (RPC) is presented in this paper. RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network. The next generation of this equipment is Active Power Quality Compensator (APQC). The major concern of these compensators is their high kVA rating. In this paper, a hybrid technique is proposed to solve aforementioned problems. A combination of SVC as an auxiliary device is employed together with the main compensators, i.e., RPC and APQC that leads on to the reduction of power rating of the main compensators. The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system. The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents. The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents. In this paper firstly, the PQ compensation procedure in AC electrified railway is analyzed step by step. Then, the control strategies for SVC and the main compensators are presented. Finally, a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.

An electrical power system (EPS) is subject to unexpected events that might cause the outage of elements such as transformers, generators, and transmission lines. For this reason, the EPS should be able to withstand the failure of one of these elements without changing its operational characteristics; this operativity functionality is called N−1 contingency. This paper proposes a methodology for the optimal location and sizing of a parallel static Var compensator (SVC) in an EPS to reestablish the stability conditions of the system before N−1 contingencies take place. The system’s stability is analyzed using the fast voltage stability index (FVSI) criterion, and the optimal SVC is determined by also considering the lowest possible cost. This research considers N−1 contingencies involving the disconnection of transmission lines. Then, the methodology analyzes every scenario in which a transmission line is disconnected. For every one of them, the algorithm finds the weakest transmission line by comparing FVSI values (the higher the FVSI, the closer the transmission line is to instability); afterward, when the weakest line is selected, by brute force, an SVC with values of 5 Mvar to 100 Mvars in steps of 5 Mvar is applied to the sending bus bar of this transmission line. Then, the SVC value capable of reestablishing each line’s FVSI to its pre-contingency value while also reestablishing each bus-bar’s voltage profile and having the lowest cost is selected as the optimal solution. The proposed methodology was tested on IEEE 14, 30, and 118 bus bars as case studies and was capable of reestablishing the FVSI in each contingency to its value prior to the outage, which indicates that the algorithm performs with 100% accuracy. Additionally, voltage profiles were also reestablished to their pre-contingency values, and in some cases, they were even higher than the original values. Finally, these results were achieved with a single solution for a unique SVC located in one bus bar that is capable of reestablishing operational conditions under all possible contingency scenarios.

In this paper, new and efficient heuristic algorithm, Differential Search Algorithm (DSA), is used for optimal choice and allocation of shunt Flexible AC transmission systems (FACTS) devices, Static Var Compensator (SVC) and Static Synchronous Compensator (STATCOM). In the proposed optimal location method, SVC and STATCOM devices are located randomly and dynamically with objective of minimizing the real power loss, improving the voltage profile and enhancing the voltage stability. The best solution sets for objectives aforementioned are achieved by minimizing each objective functions by the proposed approach. In order to evaluate the proposed methodology, it has been tested on IEEE 30 bus system and compared to another widely used optimization algorithm, Artificial Bee Colony (ABC) algorithm. The validity of the proposed optimization algorithm is proven by the results and comparative analysis with other method. [ABSTRACT FROM AUTHOR]

The Flexible AC Transmission Systems (FACTS) are the static power electronic devices that are installed and used in AC transmission networks to enhance the capability of transferring the power for providing the controllability and stability. However, the optimization of site and size of these devices is a crucial task due to their high capital cost and practical capabilities. In this paper, the optimal reactive power dispatch (ORPD) embedded with two effective controllers including the Static VAR Compensator (SVC) and Thyristor Control Series Capacitor (TCSC) is solved using a Modified Lightning Attachment Procedure Optimizer (MLAPO). The searching capability of basic LAPO is enhanced and the stagnation of basic LAPO is avoided by application of levy flight distribution and spiral orientation motion. The optimization for these devices is for reducing the power losses, voltage deviations, and the operating cost. MLAPO is examined and tested on modified IEEE30 and IEEE57 bus-standards considering SVC and TCSC. The effectiveness of MLAPO is further analyzed and compared with the outcomes of the well-known optimization techniques namely LAPO, PSO, ALO, EO, MPA, WOA and SCA with and without FACTS devices.

Aiming at the deficiencies and shortcomings of traditional reactive power compensation devices in controlling and improving voltage quality, a bilevel programming model for the coordinated optimal allocation of active and reactive power capacity of photovoltaic power generation systems, wind-driven generators, shunt capacitors and static var compensators is established based on chance-constrained programming. In the optimization model, the randomness and intermittence of the output power of the distributed generation and the reactive power regulation ability of the distributed generation are considered. The correlation of illumination, wind speed and load fluctuation is considered and affected by seasonal variation. Latin hypercube sampling method is used to deal with the correlation of random variables. Monte Carlo probabilistic power flow method is used to calculate the power flow of distribution network with intermittent distributed generation systems. The location and capacity of active and reactive power sources in outer programming are optimized by adaptive artificial fish swarm algorithm, and the allocation scheme of active and reactive power sources determined by outer programming is optimized by inner adaptive artificial fish swarm algorithm. The two-layer nested adaptive artificial fish swarm algorithm is used to solve the optimal allocation problem constructed in this paper, and the optimal allocation scheme of active and reactive power supply capacity is determined. Taking IEEE33 distribution system as an example, the feasibility and applicability of the proposed model and algorithm are verified. [ABSTRACT FROM AUTHOR]

This paper presents multi-objective congestion management of transmission lines using time-of-use (TOU) based demand response (DR) program and static var compensator (SVC). Congestion of transmission lines is managed, while system parameters such as generation fuel cost and active power losses are reduced, in addition to enhancement of bus voltages. The SVC was modeled as a reactive power injector, while the TOU-based DR was modelled using the price elasticity of demand for responsive loads. Particle swarm optimization was used for the optimal placement and sizing of the SVCs, considering the rolled-out DR program in MATLAB/MATPOWER. The DR program was first tested separately on the IEEE-30 bus test system to show its effects on the afore-mentioned system parameters. Subsequently, the DR program was combined with the SVC, and again tested on the IEEE-30 bus test system. The results showed a significant improvement of 1.414% on the voltage profile, 44.65% reduction on the generation fuel cost, and much significant 71.13% reduction on the system losses with the proposed method, compared with the Base Case Scenario (the Peak Period) where there was congestion. This shows the effectiveness of the proposed hybridized DR-SVC method in congestion management of transmission lines. [ABSTRACT FROM AUTHOR]

The use of the static Var compensator in the power system allows for greater flexibility in controlling system variables. Therefore, electric power systems expansion investments can be delayed. Inserting the static Var compensator into the transmission line alters the power flow parameters and, consequently, the voltage and current amplitudes and angles in the system to which they are connected. This work analyzes the influence of the static Var compensator on the alteration of the actuation times and the reach of the protection zones of the transmission lines that compose the electric power systems. PSCAD/EMTDC software is used to perform all modeling of electrical and control components. After the modeling, disturbances are simulated in the system, and the ANSI 21 protection function is evaluated against these abnormalities in the scenario with and without the presence of static Var compensator. The results showed an underreach of the ANSI 21 function, given the disturbances from the perspective of static Var compensators presence. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method to minimize the system losses of electrified railway traction systems by utilizing static var compensators (SVCs). We suggest a power flow analysis model for a railway system considering two types of SVC connections: line-to-ground and line-to-line connections. Furthermore, an optimal operation whose objective is to minimize the system loss is presented based on particle swarm optimization by utilizing the power flow calculation method. The proposed power flow model and optimal operation are verified using MATLAB and PSCAD simulation programs. An electrified railway traction system can be operated economically by exploiting the proposed method.

The uncertain nature of renewable energy resources (RERs) and fast demand response lead to recurring voltage violations in the power systems, which causes frequent transformer tap shifting and capacitor switching. Therefore, this paper resorts to the static var compensators (SVCs) to manage the bus voltages based on the multi-agent deep reinforcement learning (MA-DRL) algorithm. The proposed scheme includes several system agents and SVC agents to collaboratively adjust the injected reactive power to restrict the bus voltages within the normal range. All the agents are trained centrally and executed separately, which requires minimum communication cost. The IEEE 14-bus system, IEEE 300-bus system, and China 157-node urban power grid are used to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The strategic intent of the African Union is to develop a “Smart Integrated African Electric Power Super Grid” driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa’s sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Thus, the application of innovative technologies such as HVDC links can stabilize weak power systems. It is established that HVDC delivery systems reduce losses in long transmission lines transporting bulk power compared with high-voltage alternating current (HVAC) transmission lines for power wheeling. This paper evaluates the parallel operation of the Cahora Bassa 1414 km bipolar HVDC link and a weak parallel 400/330 kV alternating current (AC) link. It demonstrates the use of FACTS controllers to enhance the technical performance of an existing network, such as voltage control, and technical loss reduction. It combines an HVDC line commutated converter (LCC) and HVAC transmission lines, in hybrid notation to increase the voltage stability of the system by controlling the reactive power with a Static Var Compensator (SVC). These modern tools can increase the transmission power controllability and stability of the power network. In this study, HVDC–LCC was used with a setpoint of 1000 MW in conjunction with the 850 MVAr SVC. The results show that the technical losses were reduced by 0.24% from 84.32 MW to 60.32 MW as Apollo 275 kV SVC was utilized for voltage control. The network analysis was performed using DIgSILENT PowerFactory software that is manufactured by DIgSILENT GmbH at Gomaringen, Germany

When the power company is cutting and sending electricity, low frequency oscillation will occur in the power equipment at the harbor, which causes equipments to fail to function properly. This paper proposes an improved NSGA-II to coordinately control the power system, with the power system stabilizer and static reactive power compensator. The classical single machine system is simulated and analyzed in Matlab/Simulink software. The Strength Pareto Evolutionary Algorithm is selected to compare and analyze the different performance with the improved genetic algorithm which proposed in this paper. The results show that the PSS and SVC optimized by NSGA-II can improve the damping ratio of power system and restrain the low-frequency oscillation more effectively. [ABSTRACT FROM AUTHOR]

This paper introduces a smart coordinated allocation of distributed generation (DG) units, shunt-connected capacitors (SC), and static VAR compensators (SVC) for power loss minimization. The problem is formulated as a mixed-integer non-linear programming and is solved using a BONMIN solver embedded in General Algebraic Modeling System (GAMS). The proposed method’s evaluation was performed on the IEEE 33-bus test system, where three cases were discussed. GAMS/BONMIN was used to find optimal locations and power outputs of DGs in the first case. Simulation results, in this case, showed that losses were reduced by 48.42% with one DG unit, 58.58% with two DG units, and 65.44% with three optimally allocated DG units. In the second case, the proposed method was used to coordinate DGs and SCs, while in the third case, coordinated allocation of DG and SVC was investigated. The results showed that SC/SVC coordination further reduces active power losses. With three SCs allocated, the reduction in the active power losses was 93.5% compared to the base case, and 82.18% compared to losses in the case where only 3 DGs are connected, while in the case of three SVC allocated, it was 93.85% compared to the base case, and 82.21% compared to the case where 3 DGs are connected. The second and third cases also showed that the coordination of SC/SVC leads to an improved voltage profile, where the bus voltages are close to the acceptable range, and voltage fluctuation is significantly reduced. The comparison between different non-linear programming solvers embedded in GAMS for solving optimal power flow was also presented. [ABSTRACT FROM AUTHOR]

A constant worldwide growing load stress over a power system compelled the practice of a reactive power injection to ensure an efficient power network. For this purpose, multiple technologies exist in the knowledge market out of which this paper emphasizes the usage of the flexible alternating current transmission system (FACTS) and presents a comparative study of the static var compensator (SVC) with the static synchronous compensator (STATCOM), inducted in a real electric substation. The aim is to improve the power factor (PF) and power quality and to encounter reliably extreme conditions. A 220 kV electric substation was opted for the analysis, and both the static and dynamic conditions were observed with the help of a power system analysis tool termed PowerFactory-DIgSILENT. Multiple aspects were investigated via software simulations to assess the performance of the aforementioned FACTS devices, such as the voltage profile evaluation via the load flow analysis method (LFA), the harmonic response via the power quality and harmonic analysis tool, and the short-circuit response via the RMS simulation tool. The outcomes were verified and compared with permissible values included in the universal standards, such as IEC and IEEE. The superiority of the STATCOM over the SVC was proven in light of the simulative results.