Dynamic Active Power Research Articles

Robust hybrid control strategy for active power management in Kabertene wind farm within Algeria’s PIAT grid

The paper introduces a hybrid control strategy for optimised active power management in Algeria's Kabertene wind farm, crucial for the pole insalah-adrar-timimoune (PIAT) grid's stability. This strategy merges simultaneous interconnection and damping assignment (SIDA) passivity theory, passivity-based control (PBC), and multivariable proportional-integral-derivative (PID) controllers. This combined approach ensures frequency and voltage stability within the PIAT grid, which encompasses various elements like wind farms, solar plants, gas turbines, and dynamic impedance (Z), current (I), and active power (P) (D-ZIP), load model. By tailoring controllers for doubly fed induction generators (DFIGs) using SIDA-PBC principles and optimising internal parameters, the strategy achieves precise control of active power output. Additionally, particle swarm optimisation (PSO) refines power scheduling, which is especially beneficial for intermittent renewable sources like DFIGs. This comprehensive strategy offers numerous advantages: improved network stability, minimized voltage deviations, reduced frequency fluctuations, and enhanced integration of renewable energy sources. The paper emphasises practical implementation considerations, providing valuable guidance for efficient Kabertene wind farm operation and integration. This research contributes significantly to fostering cleaner and more reliable energy systems, facilitating the PIAT grid's transition towards sustainable energy generation.

Design and Verification of Cascaded Multilevel STATCOM Active Filter Function

STATCOM can be used as both dynamic reactive power compensation device and active power filter to improve the power quality of a power grid. This paper describes the active filter function implemented into an existing STATCOM control. The paper explains firstly the filtering control system of the STATCOM, starting from the introduction of active power filter principle, harmonic current detection and tracking control. After that, the parameter design, open-loop characterization and simulation verification of the proposed filtering control scheme are carried out. The PSCAD simulation results show that the active filtering control scheme proposed in this paper can effectively reduce the harmonic content in the system and has good stability.

Dynamic active and reactive power compensation in distribution networks using PV-STATCOMs: A tutorial using the Julia software

This document presents a tutorial regarding the use of PV-STATCOMs for dynamic active and reactive power compensation in AC distribution networks. The main idea is to guide the reader from the classical power flow formulation for AC distribution networks in the complex domain to a multi-period power flow problem using the optimization tools available in the Julia programming software. The use of PV-STATCOMs as dynamic active and reactive power compensation tools allows considering different power factors, i.e., they can work as a PV generation plant with a unitary power factor, as a purely reactive power compensator (capacitive or inductive), or as a dynamic active and reactive power compensator with a variable power factor. The Julia software was selected as a programming environment due to its excellent performance in terms of its programming interface and the use of specialized solvers for nonlinear programming problems in the complex domain, which helps introduce some concepts for the efficient operation of distribution networks while focusing on the mathematical model instead of on the solution technique. Numerical results confirm that the proposed approach, which uses the Ipopt solver, yields excellent numerical solutions in comparison with optimization methodologies recently reported in the scientific literature. A version of the IEEE 33-bus grid adapted for multi-period optimal power flow studies was employed as a test feeder. All numerical results were obtained using Julia, with the help of the JuMP optimization environment and the Ipopt solver.

Empowering Dynamic Active and Reactive Power Control: A Deep Reinforcement Learning Controller for Three-Phase Grid-Connected Electric Vehicles

Empowering Dynamic Active and Reactive Power Control: A Deep Reinforcement Learning Controller for Three-Phase Grid-Connected Electric Vehicles

A novel electric vehicle charging management with dynamic active power curtailment framework for PV-rich prosumers

A novel electric vehicle charging management with dynamic active power curtailment framework for PV-rich prosumers

An energy storage planning method for improving the security of receiving-end system considering the selection of power conversion systems

China's power demand in high load density areas is satisfied by a centralized feed of several large-capacity HVDC links, forming a typical receiving-end system, which is facing problems such as shortage of dynamic reactive power and increased risk of commutation failure. Electrochemical energy storage (ES) has characteristics such as strong dynamic active and reactive power regulation ability, rapid response and flexible control mode, making it a high-quality resource in improving the security of the receiving-end system. Therefore, it is necessary to carry out research on the methods of planning of ES in receiving-end systems. This paper mainly analyzes the role of ES in providing dynamic reactive power support. According to the different control modes of power conversion system (PCS), the ES is divided into grid-following (GFL) and grid-forming (GFM), and multi-infeed short circuit ratio (MISCR) considering both is constructed. The MISCR is taken as an objective function of the ES planning model. At the same time, the method of “accompanying network + model reconstruction” is proposed to realize the linearization calculation of MISCR. In order to compensate for the economic cost of ES investment, its energy storage function should also be used to participate in peak shaving during normal operation. Therefore, an ES planning model considering PCS selection is established, which including ES planning layer, system operation layer and accompanying network layer. Finally, the effectiveness of the proposed planning method is verified by a modified IEEE-39 system.

A Dynamic and Efficient Active Power Support Scheme Using VSC-HVDC System for Quick Frequency Restoration

A Dynamic and Efficient Active Power Support Scheme Using VSC-HVDC System for Quick Frequency Restoration

On Transient Instability Mechanism of PLL-Based VSC Connected to a Weak Grid

This paper analyzes the transient process of Phase Locked Loop (PLL) based grid-connected Voltage Source Converters (VSCs) under large disturbances by modeling the PLL dynamic model and active power loop model. With a focus on the effect of transient grid voltage changes on the stability of the PLL-based VSCs, it reveals that the mechanism of transient instability of PLL-based VSCs is different under various disturbance levels. It can be concluded that prior to the PLL losing synchronization, the power loop has already become unstable. In addition, the influence of the PLL prefilter used for asymmetrical faults on the stability criterion is analyzed. Moreover, based on the transient instability mechanism, two solutions are proposed to deal with different instability occasions, and the adaptability of these solutions is analyzed. Finally, hardware-in-the-loop experimental results validate the proposed transient instability mechanism and the proposed control strategies.

A Modified Multi-Level Inverter System for Grid-Tied DES Applications

Energy harvesting from renewable energy sources is trending in the world due to inventions in modern technology. This paper proposes a grid-tied single-phase modified W-type 81-level inverter. Inverter design equations to calculate various parameters, such as the number of voltage levels and the number of DC power sources, along with the feedback controller equations, are developed to integrate the proposed topology with an electric power grid. The modeling of the control system for the proposed topology is carried out in the synchronously rotating reference frame for single-phase systems. The PWM generation part of the proposed inverter system makes use of the binary search nearest level algorithm to efficiently track the grid voltage signal. The proposed system integrates the inverter with the grid without the need for an output filter. The efficiency analysis shows that the proposed system delivers active and reactive power to the grid with an efficiency of around 90% and a THD of 1.04%. The voltage and current waveforms for the dynamic active and reactive power flow reveal that the proposed system exhibits a good transient and steady-state response. The overall system is simulated in MATLAB/Simulink and the results are verified using a hardware implementation of the prototype circuit.

New Adaptive Broadband Full-Bridge Converter Impedance Matching Network for Giant Magnetostrictive Transducer

This article proposes an adaptive broadband full-bridge converter impedance matching network (FCIMN) between a power amplifier and the giant magnetostrictive transducer (GMT). Compared with the conventional passive impedance matching methods, the proposed one can realize the load impedance matching of power amplifiers under a wide frequency range. In this article, first, the elementary principle of operation of FCIMN is introduced mathematically. After that, a control method is proposed to achieve adaptive broadband impedance matching, including dynamic active power calculation, reactive power calculation, segmented proportional–resonant controller and combined feedback and feedforward voltage control. On this basis, the parameter design method is proposed for the operating frequency range. Finally, the simulation and laboratory-scale experimental results are provided to validate the effectiveness of the proposed FCIMN, discussions, and control method. It clearly shows that the proposed FCIMN can adaptively match load impedance for the different GMTs, broadband range, and the power amplifier power utilization factor is significantly improved.

Data-adaptive robust coordinated optimization of dynamic active and reactive power flow in active distribution networks

The uncertainty of wind power brings security and economic issues in active distribution networks. As an effective solution to these problems, the active/reactive optimization aims at minimizing the total operation cost and network loss by controlling multiple resources. This paper proposes a two-stage data-adaptive robust optimization model for the dynamic active-reactive power flow. The dynamic correlation between the uncertainties of active and reactive power is analyzed at two kinds of power factor modes of wind turbines and then is described by a linear affine decision rule. To characterize these uncertainties, a data-adaptive multi-band uncertainty set is constructed based on historical data, which allows the number of bands and the corresponding weight coefficients to be adjusted under different confidence levels. Subsequently, the conic relaxation and linearization techniques are performed to reformulate the robust optimization model as a mixed-integer second-order cone programming problem. A two-level solution framework, consisting of a column-and-constraint generation algorithm and an outer approximation algorithm, is employed to solve this problem. Simulation results on a modified IEEE 33-bus system indicate that the variable power factor mode is more suitable for describing the dynamic correlation than the constant power factor mode. Besides, the proposed model and method also show better practicality and solution efficiency than the existing ones.

Implementation of Unified Power Quality Conditioner Based on Variable Phase Angle Control Method

This paper investigates the power quality problems which occur frequently in power supply and suggests a method to mitigate the power quality problems by the implementation of UPQC. P-Q problems generally concern with voltage sags/swells and harmonic currents. Custom Power (CP) devices that mitigate these power quality problems have gained more attention in the recent decades. UPQC is Designed, modelled and setup experimentally to mitigate voltage sag/swells and harmonic currents in three phase systems. UPQC consists of Dynamic Voltage Restorer (DVR) and Active Power Filter (APF). UPQC with proposed controller algorithms effectively compensates the sag/swell in supply voltage by keeping the load voltage amplitude at 0.9-1 per unit and eliminates the load current harmonics by keeping supply current at 5% less than of Total Harmonic Distortion,simultaneously. Keywords: Custom power device,Voltage sag,swell,Harmonics. DOI: 10.7176/ISDE/12-3-03 Publication date: September 30 th 2021

An enhanced second-order-consensus-based distributed secondary frequency controller of virtual synchronous generators for isolated AC microgrids

Virtual synchronous generator (VSG) control is a promising control method in microgrid (MG) for the inertia support characteristic. However, the VSG inherits the oscillation feature of synchronous generator (SG), thus the active power and frequency oscillation may be observed when VSG control is applied. In MG, the oscillation may cause the unreasonable dynamic active power sharing among VSGs. Subsequently, the VSGs are prone to overload and even unstable, and the existing works based on consensus control cannot suppress the oscillation effectively. In order to tackle this problem, this paper proposes an enhanced second-order-consensus-based distributed secondary frequency controller by introducing the active power second-order consensus control, and reveals the oscillation suppression capacity of the second-order consensus algorithm in depth. Since there is no specific control requirement for the second-order variables, i.e., the change rate of active power and frequency of MG in steady state, the proposed controller can be simplified by replacing the integral control of second-order variables with the proportional control of first-order variables, i.e., active power and frequency, thus the communication data volume will not increase comparing to the traditional first-order-consensus-based controller. This paper also provides a small-signal model of MG with the proposed controller to evaluate the system dynamic performance and design the parameters. Finally, the simulation results verify the effectiveness of the proposed controller.

Simultaneous Provision of Dynamic Active and Reactive Power Response From Utility-Scale Battery Energy Storage Systems in Weak Grids

Utility-scale battery energy storage system (BESS) technologies have huge potential to support system frequency in low-inertia conditions via fast frequency response (FFR) as well as system voltage via dynamic reactive power response. However, technical challenges may emerge in weak grids where low system strength could cause voltage instability, eventually potentially hindering provision of FFR too. This paper provides a systematic and comprehensive analysis of the challenges, and proposes relevant solutions, for BESS in providing FFR and general dynamic active and reactive responses under low system strength conditions. In particular, first we propose a constraint to describe the negative impact of low system strength on BESS phase-locked loop (PLL) stability and possible mitigation solutions. We then investigate the negative impact of large contingencies on BESS DC-link stability and active power control by introducing d-q current-power sensitivity factors and propose a solution based on reactive power prioritization that prevents converter-level instabilities while providing simultaneous active and reactive dynamic responses. Possible negative active/reactive power interactions due to BESS converter capacity constraints and the impact of the BESS operating point are also addressed. All these issues are investigated, and the proposed solutions tested, through explicit mathematical modelling as well as dynamic simulations of the South Australia's Eyre Peninsula weak grid.

Topology optimization for harmonic vibration problems using a density-weighted norm objective function

The optimized design of structures subjected to harmonic excitation is of great interest, for both the suppression of the oscillatory response (minimization) and the design of resonant structures (maximization). This work proposes an objective function which can be used for both goals, can properly locate resonance even for large damping ratios, and can be tuned to avoid the presence of non-physical modes in regions with void or intermediate relative densities. The properties of the proposed formulation are shown using a traditional benchmark case and the formulation is compared with other two formulations presented in the literature: dynamic compliance and active power. The results show that the proposed formulation is simple to use, leading to well-defined topologies with extreme harmonic behavior, although not solving the well-known problem of discontinuous topologies.

Distributed Hierarchical Consensus-Based Economic Dispatch for Isolated AC/DC Hybrid Microgrid

In this paper, a distributed hierarchical consensus algorithm is proposed to solve the economic dispatch (ED) problem for the isolated AC/DC hybrid microgrid. At first, the whole nodes of the AC/DC hybrid microgrid are divided into two parts, that is, the leadership layer nodes and the tracking layer nodes. The leadership layer nodes update the data through their own feedback elements, while the tracking layer nodes receive the information from the leadership layer nodes and update the data. After several iterations, the two different layer nodes obtain the same state, which realizes the dynamic active power balance of the whole AC/DC microgrid. Besides, the AC sub-grid and DC sub-grid can also realize the power balance by the proposed algorithm, and the energy storage units will absorb or release active power to meet the power demand in the respective section. In addition, the constraints of the nodes are also taken into account to guarantee that the power nodes in the AC/DC hybrid microgrid should operate within their own limitations, which is necessary to realize the ED for the considered hybrid microgrid. Finally, case study and simulation results are provided to illustrate the effectiveness of the proposed hierarchal method.

Dynamic active and reactive power compensation in distribution networks with batteries: A day-ahead economic dispatch approach

This paper focuses on the problems of optimal operation of battery energy storage systems (BESSs) in distributed networks from a nonlinear programming (NLP) point of view. This proposal contains the active and reactive power capabilities of the voltage source converters that interface with the BESS independently, which implies that the BESSs have the possibility to work as dynamic energy compensators over all the four quadrants. Two radial distribution networks have been used to validate the proposed NLP model. This model has been arrived at by using the general algebraic modeling system (GAMS) optimization package. Artificial neural networks (ANN) are also employed for short-term forecasting of renewable generation based on wind and photo-voltaic sources. Numerical results show that the inclusion of reactive power capabilities of batteries reduces the daily operational cost of the network as compared to the classical unity power factor operation approach. All the simulations are made considering Colombian utility typical curves.

Carrier-Phase-Shifted Rotation Pulse-Width-Modulation Scheme for Dynamic Active Power Balance of Modules in Cascaded H-Bridge STATCOMs

In the medium-voltage power distribution system, cascaded H-bridge (CHB) static synchronous compensators (STATCOMs) are widely utilized to solve power quality issues by injecting the controlled reactive current into the system. The carrier-phase-shifted (CPS) pulse-width-modulation (PWM) scheme is preferred for CHB-STATCOMs, because it can minimize the compensating current distortion and realize the relative active power balance among the H-bridge modules. This paper reveals the influence of the carrier phase difference on the module active power balance, and proposes a carrier rotation technique with a CPS-PWM scheme to address this drawback. The rotation rules were analyzed, and the rotation time was especially designed to enhance the robustness of the system. With the proposed method, the natural dynamic active power balance of each module could be achieved, and the capacitor voltage could maintain balance without the individual capacitor voltage control or the auxiliary circuits in theory. The experimental results acquired from a downscaled CHB-STATCOM prototype demonstrated the feasibility of the proposed CPS rotation PWM scheme.

Hierarchical Model Predictive Control Strategy Based on Dynamic Active Power Dispatch for Wind Power Cluster Integration

Large-scale wind power cluster with distributed wind farms has generated the active power dispatch and control problems in the power system. In this paper, a novel hierarchical model predictive control (HMPC) strategy based on dynamic active power dispatch is proposed to improve wind power schedule and increase wind power accommodation. The strategy consists of four layers with refined time scales, including intra-day dispatch, real-time dispatch, cluster optimization, and wind farm modulation layer. A dynamic grouping strategy is specifically developed to allocate the schedule for wind farms in cluster optimization layer. In order to maximize wind power output, downward spinning reserve and transmission pathway utilization are developed in wind farm modulation layer. Meanwhile, a stratification analysis approach for ultra-short-term wind power forecasting error is presented as feedback correction to increase forecasting accuracy. The proposed strategy is evaluated by a case study in the IEEE Network with wind power cluster integration. Results show that wind power accommodation has been enhanced by use of the proposed HMPC strategy, compared with the conventional dispatch and allocation methods.

Effective Power Quality Improvement in PV Grid by using Adaptive Hysteresis Dynamic Active Power Filter Under Different Source Voltage Control Strategies

With the modernization of loads using power electronic components and dynamic loads diminishes the power quality of the system. Integration of renewable energy sources is the best solution to meet the additional power demand and also to improve the power quality problems like low power factor and harmonics distortions. In this paper, an adaptive dynamic shunt active power filter is proposed to alleviate the power quality problems like current harmonic distortions and reactive power compensation. The proposed control strategy performance is examined under different source voltage conditions under IEEE standards. Photovoltaic system is integrated at DC link of the Adaptive dynamic shunt active power filter. Proposed system performance is studied by using MATLAB/SIMULINK Environment.