Power Flow Controller Research Articles

Analysis and Dynamic Stabilization of a HighVoltage VSC-MTDC Grid with DC Power Flow Controller Connected to Extremely Weak AC Systems

Analysis and Dynamic Stabilization of a HighVoltage VSC-MTDC Grid with DC Power Flow Controller Connected to Extremely Weak AC Systems

Case-Study of an HTS Saturable Core Reactor for Power Flow Control in a Transmission Grid

Case-Study of an HTS Saturable Core Reactor for Power Flow Control in a Transmission Grid

Comparing a Multi-Terminal High Voltage Direct Current and Unified Power Flow Control for Short Circuit Level Reduction in Iraqi 400 Kv Grid

The demand for electricity has increased significantly in recent years; yet, the transmission and distribution networks are unable to meet unrestrained demands because of resource constraint. Losses in power lines exacerbate the unfavorable conditions for maximum power transfer. Recent decades have seen a rise in the use of FACTS and High Voltage Direct Current transmission in power systems due to its many advantages, which include reduced short circuit level (SCL), enhanced voltage profiles, reduced network power losses, and enhanced system reliability and safety. The paper presents a comparing study of the effectiveness of Unified Power Flow Control (UPFC) and Multi-Terminal High Voltage Direct Current (MT-HVDC) transmission in reducing short circuit current and network power losses for the Iraqi Super High Voltage (ISHV) grid. Modeling of Unified Power Flow Control and Multi-Terminal High Voltage Direct Current transmission is carried out using the Power System Simulator for Engineering (PSS/E) version 32 Package Program. The integration of multi-terminal HVDC transmission to the system resulted in a considerable decrease in short circuit levels and network power losses for the majority of buses in the system, as well as a reduction in the loading on the transmission lines in the southern region of Iraqi Super High Voltage grid, As a result, the South’s network performance will improve, hence improving Iraq’s electrical power system. Furthermore, when compared to installing a UPFC, the results showed that multi-terminal HVDC transmission reduces short circuit levels more efficiently.

Solving Optimal Power Flow Control Problem Using Honey Formation Optimization Algorithm

Solving Optimal Power Flow Control Problem Using Honey Formation Optimization Algorithm

Non Linear Modelling and Control of Unified Power Flow Controller

Non Linear Modelling and Control of Unified Power Flow Controller

Hardware in the Loop Protection Scheme of Compensated Transmission Lines With a Unified Power Flow Controller

Hardware in the Loop Protection Scheme of Compensated Transmission Lines With a Unified Power Flow Controller

Integration of UPFC in Solar PV Systems for Enhanced Green Energy Transmission

The recent world is being focused on deriving methods for using renewable energy-based systems to meet the energy demands. There are various research areas to be focused upon for making the output from these energy systems more reliable and efficient. The focus of this paper is on examining on such key component, a Unified power flow Controller (UPFC) into solar Photovoltaic (PV) structures to enhance green energy transmission and efficiency. The UPFC structure has the benefits combining the STATCOM and SSSC, which is found to be vital in regulating the active and reactive power flows within the network, ensuring stability amidst system fluctuations. The software MATLAB/SIMULINK is being used for making a 400.0-kW PV-UPFC farm, the study explores the effect of UPFC on enhancing power quality and stability, addressing real-world challenges like harmonics and voltage fluctuations like sags/swells. The work also delves into novel control strategies, consisting of using Proportional-integral (PI) controllers and advanced optimization techniques, to manage the power flow effectively. It can be concluded that the research highlights the UPFC’s capability in mitigating issues inherent in integrating solar energy into the grid, inclusive of voltage rise, reverse power flow, and system instability, by means of showcasing more desirable system voltage profiles and decreased energy oscillations in the designed system.

A Power Factors Full-Dimensionally Hunted Power Distribution Strategy for Railway Power Flow Controller Considering Regenerative Braking

Railway power flow controller (RPFC), as a promising technical route for railway power regulation, its rating determinization and the related flexible power regulation perplex designers and hinder large-scale applications, especially when the regenerative braking energy (RBE) is non-negligible. In this paper, a general power factors full-dimensionally hunted power distribution strategy (PFFDH-PDS), applicable for both off-line design & real-time control, is proposed. Two key methods are developed: 1) Full-dimensionally hunting the power factors (PFs) under the developed mathematic framework, from which the global optimal compensating power and RPFC's rating can be worked out; 2) Precisely partitioning two-phase loads on their PF-P and PF-PF distributing panels; in both methods, RBE is considered. By adopting PFFDH-PDS, RPFC's rating can be reduced by almost 60% compared to the conventional method, while the system has satisfactory grid-connection compatibility. Finally, the effectiveness and performance of the proposal are verified & conducted by real-measured data.

An efficient high-gain bidirectional interleaved boost converter for PV integration to DC microgrid.

The design of a power electronic interface for high voltage difference DC buses is a key aspect in DC microgrid applications. A multi-port non isolated interleaved high-voltage gain bidirectional converter, which facilitates bidirectional power transfer and islanded operation in a DC microgrid, is presented in this paper. The forward high-voltage transfer ratio is achieved using a voltage multiplier circuit, and the high-gain step-down power conversion is performed using a resonant power module. A novel power transfer selection algorithm is proposed to control power flow among the interfaces of the RES, ESS, and DC grid converters, which utilizes the net power difference as the basis for switching the converter. The proposed converter is simulated for a 24 V PV source, 12 V battery, and 400 V DC grid interface using MATLAB/SIMULINK. A 200 W hardware prototype is implemented. The simulation results for voltages, currents, and power flow among RES, ESS, and microgrid DC bus proved an excellent voltage regulation, efficient power conversion, and a feasible duty cycle range with high voltage gain. These observations are validated through equivalent experimental results. A comparison is made regarding achieved gain, component sizing, achievable power transfer modes, efficiency, and control complexity with existing converters for DC microgrid applications. The presented topology proved to be a better interface with multiple-mode support with high efficiency.

A Fast-response Power-Flow Control Strategy of MMC-UPFC based on Active Disturbance Rejection Control

A Fast-response Power-Flow Control Strategy of MMC-UPFC based on Active Disturbance Rejection Control

A coordinated modelling and control of modified pumped storage governor with unified power flow controller to damp low frequency oscillations in power system for stochastic renewable penetrations

A modern power system network is more susceptible to oscillatory instability problem due to power oscillations caused by uncertain penetration of renewable sources. Also, pumped storage hydro power generation (PSHPG) is going to take important role for energy storage and management with varying renewable penetrations, but their governors need to be utilized efficiently for power oscillation damping. In this work a coordinated modified pumped storage governor with fractional parallel unified power flow controller (FPUPFC) has been modelled and controlled to damp angular frequency variations in power system. The prime objective of this work is to enhance efficacy of pumped storage hydro turbine governors integrated into an expert system with UPFC to take part in electromechanical oscillation damping. Here the governor is modified by fractional order PID action with additional phase compensation and in FPUPFC both series and shunt converters are controlled simultaneously by parallel fractional lead-lag based control action. The power system considered here consists of hydro generators of 100 MVA with 90.94 MW rated turbine output power with different operating conditions for two area 4 generators and 39 bus 10 generators multimachine renewable integrated system. It has been observed that efficacy of pumped storage hydro turbine governor action has been much improved when coordinated with FPUFC control action. A new hybridized modified differential evolution with fractional particle swarm optimization (MDEFPSO) is proposed to tune the parameters of proposed controller, with a multi-objective function considering variation in speed and real power deviations, settling time, overshoot and undershoot of system response.

Double-Side Feeding and Reactive Power Compensation Using the Railway Interline Power Flow Controller

This paper gives an overview of the operating characteristics of the railway interline power flow controller (RIPFC) regarding the capability of transferring active power between two sections of an electrified railway line separated by a neutral zone and proposes its use for compensating the power factor at the substation instead of regulating the voltage level at the neutral zone. The basic analysis is based on simplified steady-state models for the energy supply architecture, while detailed time-domain simulations are used for more realistic tests. The paper mainly focus on active power balancing between two neighbouring substations and the global losses in the system. Other functionalities of the RIPFC system are also analysed, like reactive power compensation at the substations. The paper presents the main operating principles of the system, shows results for some representative scenarios (generic and reduced) and discusses the results. The most relevant conclusions are related to substation active power balancing and peak shaving, power factor compensation in the substation, voltage stability at the neutral zone and system power losses.

Power flow control in a modular converter with energy storage

AbstractUsing modularized power converters with scalable energy storage in particle accelerators can be further enhanced with controls that can be adapted to optimise different design targets, such as to minimise the front‐end stage peak current, the depth of discharge of electrolytic capacitors or the thermal cycling of semiconductors. This paper proposes a control system that is able to individually adjust the power flow of the converter modules under pre‐defined load profiles, and hence separates the use of energy storage and grid connection even under rapid cycling. The paper briefly summarises the characteristics of the modular converter and proposes four energy control strategies that have been validated by simulation as well as experimentally on a 800 kW full scale prototype. It is shown that by applying each strategy, the corresponding design objectives can be achieved, for example, optimal utilisation of the energy storage systems or minimised current stress in the semiconductors.

AUTOMATIC ADJUSTMENT OF REACTIVE POWER BY FACTS DEVICES UNDER CONDITIONS OF VOLTAGE INSTABILITY IN THE ELECTRIC NETWORK

This article describes the problem of automatic regulation of reactive power using electronic devices FACTS (Flexible AC Transmission Systems): static synchronous compensator (STATCOM) and unified power flow controller (UPFC). With the help of a complex writing form, the following are determined: voltages at the installation nodes of the FACTS device and loads, currents of loads, power sources and electronic compensators in case of voltage instability at the load node of the electrical network. Voltages and currents are determined using the node-voltage method. The task of STATCOM is partial or full compensation of reactive power. During the reduction of the voltage at the load node, the reactive power generated by the power source decreases. The STATCOM should partially or fully compensate for the reactive power imbalance as quickly as possible. However, at the same time, it is not possible to fully compensate for the voltage reduction. A series-parallel or parallel-series UPFC can be used to solve this problem. As a result of using the UPFC, it is possible to automatically raise the voltage level to acceptable values with the help of the UPFC series compensator. The analysis shows that the parallel-serial UPFC is characterized by the stability of operation. In the case of using a series-parallel UPFC, there are restrictions on the ability to adjust the imaginary voltage component of the series compensator, since the angle of the voltage vector changes, which causes a failure in the operation of the regulator of the parallel compensator UPFC.

Stochastic model for active distribution networks planning: An analysis of the combination of active network management schemes

The widespread adoption of distributed generation (DG) is changing the operation of distribution networks. To increase the control of power flows and avoid the detriments of DG intermittency, active distribution networks (ADN) emerge as a feasible solution. In this paper, we propose a convex model for ADN expansion planning. Four active network management (ANM) schemes are considered: DG active power curtailment, DG reactive power control, on-load tap changer (OLTC) tap adjustment, and shunt compensation device control. The problem is formulated as a mixed integer second-order cone programming problem (MISOCP) using the distflow equations and second-order cone relaxations (SOCR). By scenario analysis, we address the uncertainty associated with power demand, renewable generation, and electricity prices. The proposed model is used to study the benefits of different combinations of ANM schemes to a modified IEEE 33-bus system and compare them with the individual benefits of each scheme. The results indicate that ANM schemes can reduce total network costs, reduce losses, delay network reinforcement, and improve the voltage profile. In addition, some combinations of schemes develop synergies in which the combined economic benefits are greater than the sum of the individual benefits.

Robust energy storage system for stable in wind and solar

Energy storage systems (ESS) have become a conspicuous research hotspot since they store power and supply it during peak hours. Existing storage systems must be replaced by advanced energy storage with improved performance, energy management, and a control interface due to issues with size, dependability, and charging/discharging. The suggested robust energy retention system uses a battery and a super-capacitor to generate power from wind and solar energy. A Multiport DC converter with a buck-boost capacitor is used to properly discharge the stored energy to DC loads via a DC bus. The inverter is then delivered to a Power Flow Controller (PFC) and a Voltage Source Inverter (VSI). The Gravitational Search Algorithm (GSA) method optimizes the power controller settings based on the fluctuation of the system's active and reactive power. The optimization method ensures improved power flow while dealing with the least amount of power variance in imbalanced load situations. Based on the power variation, the proposed method generates appropriate control signals for the inverter system. The covers convert the inverter and reduce harmonics with a controller. Furthermore, the inverter AC supplied to the AC bus is converted into reactive power by an inductive load, and unwanted signals and harmonics are extracted using a Cascaded C-type filter. As a result, the described method has preserved total harmonic distortion, electrical efficiency, and finer transient stability.

Thermal Constrained Energy Optimization of Railway Cophase Systems With ESS Integration—An FRA-Pruned DQN Approach

This paper investigates the railway co-phase traction power supply system (TPSS) with a power flow controller (PFC) to address the power quality and neutral section issues. To collect the regenerative energy and achieve a more flexible power flow, the energy storage system (ESS) is integrated into the co-phase system. As the key components, the reliability of power electronics modules in PFC and battery cells in ESS is highly related to their thermal performance. It is therefore vital to consider their operational thermal dynamics, leading to the proposal of a deep Q network (DQN) based thermal constrained energy management strategy in this paper. Firstly, the system power flow model and electrothermal models for power electronics modules and battery cells are all established. Then, a DQN method is adopted to learn an optimized policy for peak power shaving while meetings thermal constraints. Finally, an FRA-based pruning method is proposed to reshape the agent to become more compact without sacrificing its performance. Case studies confirm that the proposed strategy can effectively reduce the peak traction power supply by up to 42.0%, and achieve up to 94.1% thermal reduction. The FRA-based pruning can achieve up to 89.9% agent size reduction and 87.2% computation savings.

Optimized power flow control for PV with hybrid energy storage system HESS in low voltage DC microgrid

Due to the intermittent nature of solar irradiation, it is inevitable to integrate the system of energy storage in the PV standalone system. In this paper, Energy Storage System ESS composed of a battery bank and Supercapacitor SC has been employed to maintain power supply to the load. Because of the fast rate of charge/discharge of SC, it would handle the surge transient energy and that would reduce the required capacity of the battery, increase the life span, and lessen the maintenance cost. The control strategies ensure well power flow control between the PV system and ESS and thus meet the load demand, moreover sustain the DC-link voltage regulated. In the implemented control techniques, a protective improvement is proposed which would limit overcharging of the battery. That would minimize battery degradation and enhance the reliability of the system. This is performed by employing the battery uncompensated power to reduce the stress on the battery during the large fluctuations in the power due to load/irradiance variation. The control approach is based on providing optimal reference current for the ESS with fast dynamic response and reduce the computational burden when implementing in real-time, hence stable power could be delivered to the load. Moreover, the generated PV power is controlled based on the battery charging state and the demand power and this would ensure stable control of DC output voltage. The aforementioned points have led to vigorous PV system having a long-life battery and are capable of preserving energy balance between generations and load even at the abrupt load/solar irradiation variations. . A profile of solar irradiance for selected area has obtained and the system is tested under these data, and it has shown well dynamic response and this could be used for consideration of prototype implementation. The proposed control system is simulated by MATLAB/Simulink and the results show good performance under different scenarios of load/solar irradiation variations

A Novel Direct-Injection Universal Power Flow and Quality Control Circuit

A Novel Direct-Injection Universal Power Flow and Quality Control Circuit

Independent Fast Phase Shifting Transformer: A Flexible and High-Precision Power Flow Controller

Independent Fast Phase Shifting Transformer: A Flexible and High-Precision Power Flow Controller