Amount Of Active Power Research Articles

Power System Analysis during Fast Desynchronization from Synchronous Area and Operation in Islanded Mode

In a constantly and rapidly changing global environment, one of the main priority tasks for every country is preserving, maintaining, and operating an independent and individually robust and stable energy system. This paper aims at researching electrical power systems’ (EPSs) behavior during desynchronization from a synchronous area, its stability in islanded mode, and its synchronization. The analysis of EPS behavior was accomplished utilizing numerical simulations in a widely used programming/simulation package. The sudden tripping of the EPS into an isolated island mode with known generation and load values was simulated, analyzed, and discussed. We investigated the behavior of an isolated EPS in the case of the loss of a certain amount of active power, and determined the maximum power that must be available to ensure the reliable operation of the isolated EPS and the power reserve that must be maintained to prevent the EPS from triggering UFLS. The simulation of the synchronization of an isolated EPS with a synchronous area was accomplished and analyzed. The obtained results were applied to reveal the sequence of actions that will help an EPS to ensure and maintain the stable and reliable operation of electrical installations during desynchronization.

Load Flow Analysis After the Entry of Renewable Power Plants in the Sulselrabar System

Power flow analysis in an electric power system is an analysis that reveals the performance of an electric power system and the flow of power (active and reactive) for certain conditions when the system is working. The analysis was carried out using the ETAP 16.00 software, the method used was the newton rapshon by taking a case study of normal conditions. From the results of the study, it can be seen that the power flow that occurs in each channel of the 150 kV system in the South Sulawesi system. The amount of active power (MW) that occurs during normal conditions based on the simulation is 1730.87 MW, where the active power is the largest, which is 171 MW from BUS15_TLASA to BUS13_SGMNSA. For the voltage data, there is a slight comparison of the voltage during the simulation compared to the PLN data.

Study on the Capacity of an Active Phase Controller for Autonomous Grid Connection

For the efficient power allocation of the distribution line, several studies on intelligent distribution management systems that enable connection or separation between distribution networks are being conducted. However, in case the systems are linked together and if the voltage and phase of each distribution network are different, uncontrolled circulating current and inrush current flow into the line. To resolve this, we introduced the active phase controller (APC) as a solution and performed an analysis using the capacity calculation method for the APC connected to each distribution network. When connecting lines between distribution networks, the phase of each contact was ensured to be the same. Specifically, the phase value compensated by each APC is different because the amounts of active power and reactive power to be controlled are also different. In this study, we analyzed the APC capacity according to the impedance state of the distribution line and calculated the APC output voltage for the phase matching of each distribution network at the connection point. As a result, the minimum design capacity of APC was derived; moreover, simulation results were used to validate the analysis.

Voltage Stability Constrained OPF in Multi-Micro-Grid Considering Demand Response Programs

In this article, a new approach is proposed for the voltage stability constrained optimal power flow in a multi-micro-grid (MMG) environment. In the proposed optimization problem, locational marginal pricing (LMP), demand response (DR) programs, active and reactive power generation cost for different types of renewable energy resources such as photovoltaic, wind turbine, microturbine, diesel generator, and combined heat and power (CHP) systems are used for real simulation of the MMG system. Two main types of DR programs, namely peak clipping and load shifting DR programs, are considered in the proposed methodology. In the peak clipping DR programs, LMP is calculated for each bus of the MMG. Then, the candidate loads, selected to be curtailed by the market mechanism, are paid based on the LMP values. In load shifting DR programs, the loads are paid for decreasing their amount of active power at peak hours. In this approach, the decreased active and reactive powers are shifted to off-peak times. The optimization method is formulated as nonlinear programing in GAMS software and simulated on a 55-bus MMG test system. The results of the proposed method are compared with the existing methods and the outcomes confirm that superior results in cost function are obtained using the proposed approach.

ОПРЕДЕЛЕНИЕ КРУТЯЩЕГО МОМЕНТА ПРИ СВЕРЛЕНИИ УГЛЕПЛАСТИКА

The article considers the issue of the definition of torque, which occurs when drilling polymer composite materials - carbon fiber. The amount of torque during drilling is important, as this size counts on the strength of the part of the drilling machine mechanism, pick up the power of the drive, calculate the strength of the cutting tool. The torque values can be obtained by different approaches, for example, during a natural experiment. But a natural experiment requires expensive force measuring equipment in the form of a dynamometric platform. To determine the torque, it is proposed to use a power measurement in a stable drilling mode, then the amount of active power to translate into torque. The degree of proximity of the results of the measurements of the measured parameter is close to the results obtained by empirical expressions. However, due to the differences in methods, it is not correct to consider the c onvergence of torque results.

Voltage Control Method for Active Distribution Networks Based on Regional Power Coordination

As loads connected to active distribution network (ADN) grow, ADN’s voltage safety issues are becoming more serious. At present, the solution is mainly to build more distributed generation (DG) or to adjust the reactive power in the whole network, but the former needs a lot of investment while the latter requires a large amount of communication equipment and it takes a long time to calculate the adjustment amount of reactive power and to coordinate reactive power compensation equipment. When the loads are heavy, there will still be drawbacks of insufficient reactive power. Therefore, this paper analyzes the relationship between the active power, reactive power, and the voltage in the ADN. Through the autonomous region (AR) division, a voltage control method based on the active power variation and adjustable power in the AR is proposed. According to the relationship between the amount of active power and the adjustable amount active power, the active power control, the reactive power control, and the coordinated control of active power reactive power control are adopted to adjust the DGs’ output to stabilize the bus voltage. The simulation results show that the proposed method can effectively improve the voltage control capability of ADN and can enable it to operate normally under greater power changes. Through the control method in this paper, the communication requirements are greatly reduced and the calculation time is effectively shortened and is more adaptable.

Research on an Asymmetric Fault Control Strategy for an AC/AC System Based on a Modular Multilevel Matrix Converter

This paper studies control strategies for an AC/AC system based on a modular multilevel matrix converter (M3C) when an asymmetric fault occurs in the secondary side ac system. Firstly, the operating principle of M3C is briefly introduced and verified by simulation. Then, based on its mathematical model by double αβ0 transformation, the decoupled control strategies for the primary side and secondary side systems are designed. In view of the asymmetric fault condition of the secondary side system, the positive sequence and negative sequence components of voltages and currents are separated and extracted, and then a proportional resonant controller (PR) is used to regulate the positive and negative sequence currents at the same time to realize decoupled current control in the αβ reference frames. The capacitor voltage balancing control, which consists of an inter-subconverter balancing control and an inner-subconverter balancing control, is realized by adjusting four circulating currents. Finally, the proposed control strategy is validated by simulation in the PSCAD/EMTDC software (Manitoba HVDC Research Center, Canada). The result shows that during the period of the BC-phase short-circuit fault occurring in the secondary side system, the whole system can still operate stably and transmit a certain amount of active power, according to their set values. Furthermore, the capacitor voltages are balanced, with a slight increase during the fault period. The simulation results verify the effectiveness of the proposed control strategy.

Análisis del uso de micro convertidores DC/DC enfocados en la extracción máxima de energía en una granja fotovoltaica

Este trabajo presenta un estudio amplio del trabajo publicado en la revista INCISCOS 2018 títulado “Improving of the Photovoltaic High Power Plant Generation Using DC/DC Micro Converters”;está enfocado en incrementar la cantidad de energía eléctrica generada de una Planta Fotovoltaica ubicada en Salinas, provincia de Imbabura-Ecuador, mediante la inclusión de micro convertidores DC/DC en los arreglos de los paneles fotovoltaicos y a partir de la implementación de una adecuada técnica de seguimiento del punto de máxima potencia. Los resultados indican que la inserción de los convertidores DC/DC en el sistema provocan un aumento en la cantidad de energía activa. Se realiza el análisis tanto con variaciones de la radiación solar como cambios en la temperatura ambiente.

Series Capacitor Compensated AC Filterless Flexible LCC HVDC With Enhanced Power Transfer Under Unbalanced Faults

This paper introduces significant performance enhancements to the ac filterless LCC HVDC by including fixed series capacitors at the primary side of a converter transformer. In terms of technical performance, 1) the amount of active power that can be transmitted is increased by more than 60% compared with ac filterless LCC HVDC, especially under severe unbalanced fault such as single-phase fault (most common fault in power systems); 2) the required voltage level of the controllable capacitor for Commutation Failure (CF) elimination is reduced by more than 70%, which leads to considerable reductions of the associated costs and losses. In terms of economic performance, due to the reduction of the required voltage from controllable capacitors (hence, the number of power electronic devices), the cost of the proposed converter station is lower than that of the ac filterless LCC HVDC. Theoretical analysis is presented to illustrate the performance enhancements and select the size of the series capacitor. Simulation results for various kinds of faults and cost analysis are presented to validate the technical and economic performances of the proposed method. Comparisons are made with ac filterless LCC HVDC. Finally, various practical issues and possible solutions are discussed.

Renewable Energy–Supported Hybrid Active Power Filter for Grid-Connected Application

Abstract This research article presents a Photovoltaic (PV) and battery-supported Series Hybrid Active Power Filter (SHAPF), which includes a series APF (SAPF), parallel-connected passive filter, and PV system with a battery energy storage unit. The PV-supported SHAPF provides compensation against the voltage harmonics, current harmonics, and voltage interruption for a whole day. The SHAPF systems need certainty in order to provide active power to the power system to maintain the load voltage level during voltage sag. Conventionally, the SAPF has the capacity to compensate for a limited amount of active power in the system. Thus, additional energy sources need to be added into the dc link of the SAPF. The proposed SHAPF circuitry utilizes the renewable energy source with an energy storage unit to meet the dc-link voltage requirement of the SAPF. Additionally, it exports the power that is generated in the PV system to the load. The series inverter is used to supply part of or the entire reactive power required by the load along with compensating the sag and swell, supply voltage unbalance, and distortions. This is achieved by controlling the phase angle and the magnitude of series-injected voltage, which is called the power angle control method. The fuzzy logic controller-based power angle control method is employed to compensate the voltage-based disturbances in the distribution system. The performance of the PV and battery-supported SHAPF is evaluated by conducting MATLAB/Simulink simulation and experimental studies.

Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

The low voltage ride-through (LVRT) capability is one of the challenges faced by the integration of large-scale photovoltaic (PV) power stations into electrical grid which has not been fully investigated. Therefore, this paper presents a comprehensive control strategy of single-stage PV power plant to enhance the LVRT capability based on the Malaysian standards and modern grid codes connection requirements. The proposed control overcomes the problems of dc-link over-voltage and ac over-current that may cause disconnection or damage to the inverter. For this purpose, dc-chopper brake controller and current limiter are used to absorb the excessive dc-voltage and limits excessive ac current, respectively. This control strategy can also ensure the reactive power support through the injection of reactive current according to the standard requirements as soon as the voltage sag is detected. Furthermore, to keep the power balance between both sides of the inverter, PV array can generate possible amount of active power according to the rating of grid inverter and voltage sag depth by the operating in different modes. The results illustrate that the proposed control strategy is effective, not only to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults.

AdaptiveQ–VScheme for the Voltage Control of a DFIG-Based Wind Power Plant

Wind generators within a wind power plant (WPP) will produce different amounts of active power because of the wake effect, and therefore, they have different reactive power capabilities. This paper proposes an adaptive reactive power to the voltage (Q-V) scheme for the voltage control of a doubly fed induction generator (DFIG)-based WPP. In the proposed scheme, the WPP controller uses a voltage control mode and sends a voltage error signal to each DFIG. The DFIG controller also employs a voltage control mode utilizing the adaptive Q-V characteristics depending on the reactive power capability such that a DFIG with a larger reactive power capability will inject more reactive power to ensure fast voltage recovery. Test results indicate that the proposed scheme can recover the voltage within a short time, even for a grid fault with a small short-circuit ratio, by making use of the available reactive power of a WPP and differentiating the reactive power injection in proportion to the reactive power capability. This will, therefore, help to reduce the additional reactive power and ensure fast voltage recovery.

Performance and Analysis of Reactive Power Compensation by Unified Power Flow Controller

The Unified Power Flow Controller (UPFC) is the most versatile of the FACTS controllers envisaged so far. The main function of the UPFC is to control the flow of real and reactive power by injection of a voltage in series with the transmission line. Both the magnitude and the phase angle of the voltage can be varied independently. Real and Reactive power flow control can allow for power flow in prescribed routes, loading of transmission lines close to their thermal limits and can be utilized for improving transient and small signal stability of the power system. In this paper UPFC is incorporated in a SMIB (Single Machine Infinite Bus) system and the response of SMIB system has been recorded with and without UPFC, thereafter the comparison of both the output has been done. When no UPFC is installed, real and reactive power through the transmission line cannot be controlled. This paper presents control and performance of UPFC intended for installation on that transmission line to control power flow. Installing the UPFC makes it possible to control amount of active power flowing through the line. Simulations are carried out using MATLAB software to validate the performance of the UPFC.

Coordinated V-f and P-Q Control of Solar Photovoltaic Generators With MPPT and Battery Storage in Microgrids

The microgrid concept allows small distributed energy resources (DERs) to act in a coordinated manner to provide a necessary amount of active power and ancillary service when required. This paper proposes an approach of coordinated and integrated control of solar PV generators with the maximum power point tracking (MPPT) control and battery storage control to provide voltage and frequency (V-f) support to an islanded microgrid. Also, active and nonactive/reactive power (P-Q) control with solar PV, MPPT and battery storage is proposed for the grid connected mode. The control strategies show effective coordination between inverter V-f (or P-Q) control, MPPT control, and energy storage charging and discharging control. The paper also shows an effective coordination among participating microresources while considering the case of changing irradiance and battery state of charge (SOC) constraint. The simulation studies are carried out with the IEEE 13-bus feeder test system in grid connected and islanded microgrid modes. The results clearly verify the effectiveness of proposed control methods. The simulations are carried out in Matlab and Simpowersystems.

Mechanism of Large Scale Cascading Trip-Off of Wind Turbine Generators

This paper analyses the mechanism of large scale cascading trip-off failures of wind turbine generators in China, focuses on the reasons of trip-off caused by overvoltage. It analyses the model of Doubly Fed Induction Generation (DFIG) and builds a model of a wind farm that is composed of Doubly Fed Induction generators in DIgSILENT. The wind farm A with capacity of 175MW and wind farm B with capacity of 175MW is accessed to the nine bus system. The simulation reproduces the processes of the cascading trip-off of wind turbine generators caused by undervoltage and overvoltage. The trip-off caused by undervoltage is due to the lack of Low Voltage Ride Through (LVRT). And that the capacitive reactive power compensation device is not timely removed leads to a large surplus of reactive power, then the voltage rises, so the wind turbine generators trip off because of overvoltage. By setting the contrast scenario, the result shows that if capacitive reactive power compensation device is promptly removed after the loss of a large amount of active power, the wind turbine generators will not trip off because of overvoltage.

Design Study of a Converter Interface Interconnecting Energy Storage With the DC Link of a StatCom

Voltage-source converters (VSC) have been widely utilized to provide instantaneous reactive power support to power systems, an application referred to as static synchronous compensator (StatCom). The integration of energy storage (ES) into a StatCom makes it possible for the StatCom to provide a certain amount of active power as well as reactive power support. The possible benefit of the additional active power of a StatCom can be power oscillation damping capability, mitigation of phase-jump-related disturbances, etc. Direct connection of an ES device to the dc link of the VSC incurs an unnecessarily high-voltage rating of the VSC due to the considerable voltage swing associated with the ES device. Dual thyristor converter topology has been proposed as the interface between the ES and the dc link of the VSC. In this paper, a cost estimation for systems with the proposed interface topology is presented regarding three types of ES: capacitors, supercapacitors, and batteries. The study shows potential cost savings with utilization of the proposed interface topology. In addition, a cost comparison between different types of ES is presented, providing a guideline for the choice of ES in these kinds of applications.

Design and Analysis of a Controller for a Converter Interface Interconnecting an Energy Storage With the Dc Link of a VSC

Voltage source converters (VSC) have been widely utilized to provide instantaneous reactive power support to power systems, an application referred to as static synchronous compensator (StatCom). Integration of energy storage (ES) into a StatCom makes it possible for the StatCom to provide a certain amount of active power as well as reactive power support. The possible benefit of the additional active power support of a StatCom can be power oscillation damping capability, mitigation of phase-jump related disturbances, etc. Direct connection of an ES device to the dc link of the VSC incurs unnecessarily high voltage rating of the VSC due to the considerable voltage swing associated with the ES device. In order to reduce the total cost, a dual thyristor converter topology has been proposed as the interface between the ES and the dc link of the VSC. In this paper, dynamics of the proposed system are investigated. Control strategies are proposed and verified by simulations with PSCAD/EMTDC.

Harmony Search Algorithm for Optimal Placement Problem of Distributed Generations

This paper presents a application of Harmony Search (HS) algorithm for optimal placement of distributed generations(DGs) in distribution systems. In optimization procedure, the HS algorithm denotes the searching ability for the global optimal solution with simple coding of the iteration procedure, and shows the fast convergence characteristics for getting solutions. The HS algorithm is tested on 9 buses and 69 buses distribution systems, and the results prove its effectiveness to determine appropriate placement points of DGs and reducing amount of active power without the occurrence of any mis-determination in selection of its capacity.