scholarly journals Real-time active and reactive power regulation in power systems with tap-changing transformers and controllable loads

2016 ◽  
Vol 5 ◽  
pp. 27-38 ◽  
Author(s):  
Xuan Zhang ◽  
Ren Kang ◽  
Malcolm McCulloch ◽  
Antonis Papachristodoulou
Keyword(s):  
Power Systems ◽  
Real Time ◽  
Reactive Power ◽  
Active And Reactive Power ◽  
Power Regulation

scholarly journals Power Hardware-in-the-Loop-Based Performance Analysis of Different Converter Controllers for Fast Active Power Regulation in Low-Inertia Power Systems

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3274
Author(s):  
Jose Rueda Torres ◽  
Zameer Ahmad ◽  
Nidarshan Veera Kumar ◽  
Elyas Rakhshani ◽  
Ebrahim Adabi ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Power Systems ◽  
Real Time ◽  
Control Strategies ◽  
Active Power ◽  
Power Electronic ◽  
Hardware In The Loop ◽  
Digital Controllers ◽  
Power Regulation ◽  
The Impact

Future electrical power systems will be dominated by power electronic converters, which are deployed for the integration of renewable power plants, responsive demand, and different types of storage systems. The stability of such systems will strongly depend on the control strategies attached to the converters. In this context, laboratory-scale setups are becoming the key tools for prototyping and evaluating the performance and robustness of different converter technologies and control strategies. The performance evaluation of control strategies for dynamic frequency support using fast active power regulation (FAPR) requires the urgent development of a suitable power hardware-in-the-loop (PHIL) setup. In this paper, the most prominent emerging types of FAPR are selected and studied: droop-based FAPR, droop derivative-based FAPR, and virtual synchronous power (VSP)-based FAPR. A novel setup for PHIL-based performance evaluation of these strategies is proposed. The setup combines the advanced modeling and simulation functions of a real-time digital simulation platform (RTDS), an external programmable unit to implement the studied FAPR control strategies as digital controllers, and actual hardware. The hardware setup consists of a grid emulator to recreate the dynamic response as seen from the interface bus of the grid side converter of a power electronic-interfaced device (e.g., type-IV wind turbines), and a mockup voltage source converter (VSC, i.e., a device under test (DUT)). The DUT is virtually interfaced to one high-voltage bus of the electromagnetic transient (EMT) representation of a variant of the IEEE 9 bus test system, which has been modified to consider an operating condition with 52% of the total supply provided by wind power generation. The selected and programmed FAPR strategies are applied to the DUT, with the ultimate goal of ascertaining its feasibility and effectiveness with respect to the pure software-based EMT representation performed in real time. Particularly, the time-varying response of the active power injection by each FAPR control strategy and the impact on the instantaneous frequency excursions occurring in the frequency containment periods are analyzed. The performed tests show the degree of improvements on both the rate-of-change-of-frequency (RoCoF) and the maximum frequency excursion (e.g., nadir).

Coordinative real-time sub-transmission volt–var control for reactive power regulation between transmission and distribution systems

2019 ◽  
Vol 13 (11) ◽  
pp. 2006-2014 ◽  
Author(s):  
Xinda Ke ◽  
Nader Samaan ◽  
Jesse Holzer ◽  
Renke Huang ◽  
Bharat Vyakaranam ◽  
...  
Keyword(s):  
Real Time ◽  
Distribution Systems ◽  
Reactive Power ◽  
Power Regulation ◽  
Transmission And Distribution

scholarly journals A new approach to three-phase asynchronous motor model for electric power system analysis

2021 ◽  
Vol 12 (4) ◽  
pp. 2083
Author(s):  
Laura Collazo Solar ◽  
Angel A. Costa Montiel ◽  
Miriam Vilaragut Llanes ◽  
Vladimir Sousa Santos
Keyword(s):  
Power Systems ◽  
Reactive Power ◽  
Mechanical Load ◽  
Asynchronous Motor ◽  
Electrical Power ◽  
Variable Load ◽  
Electrical Power Systems ◽  
Active And Reactive Power ◽  
Voltage Variation ◽  
Three Phase

In this paper, a new steady-state model of a three-phase asynchronous motor is proposed to be used in the studies of electrical power systems. The model allows for obtaining the response of the demand for active and reactive power as a function of voltage and frequency. The contribution of the model is the integration of the characteristics of the mechanical load that can drive motors, either constant or variable load. The model was evaluated on a 2500 kW and 6000 V motor, for the two types of mechanical load, in a wide range of voltage and frequency, as well as four load factors. As a result of the evaluation, it was possible to verify that, for the nominal frequency and voltage variation, the type of load does not influence the behavior of the powers and that the reactive power is very sensitive to the voltage variation. In the nominal voltage and frequency deviation scenario, it was found that the type of load influences the behavior of the active and reactive power, especially in the variable load. The results demonstrate the importance of considering the model proposed in the simulation software of electrical power systems.

scholarly journals Two-Stage Active and Reactive Power Coordinated Optimal Dispatch for Active Distribution Network Considering Load Flexibility

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5922
Author(s):  
Yu Zhang ◽  
Xiaohui Song ◽  
Yong Li ◽  
Zilong Zeng ◽  
Chenchen Yong ◽  
...  
Keyword(s):  
Real Time ◽  
Prediction Error ◽  
Reactive Power ◽  
Distribution Network ◽  
Constant Current ◽  
Economic Losses ◽  
Time Varying ◽  
Two Stage ◽  
Active Distribution Network ◽  
Active And Reactive Power

A high proportion of renewable energy connected to the power grid has caused power quality problems. Voltage-sensitive loads are extremely susceptible to voltage fluctuations, causing power system safety issues and economic losses. Considering the uncertainty factor and the time-varying characteristic, a linearized random ZIP model (constant impedance (Z), constant current (I), and constant power (P)) with time-varying characteristics was proposed. In order to improve the voltage quality of the voltage-sensitive loads in the day-here stage in an active distribution network (ADN), a linearized two-stage active and reactive power coordinated stochastic optimization model was established. The day-ahead active and reactive power coordination optimization was to smooth the large voltage fluctuation and develop a reserve plan to eliminate the unbalanced power caused by the prediction error in the day-here optimization. In the day-here real-time redispatch, the voltage was further improved by the continuous reactive power compensation device. Finally, the simulation results on the IEEE-33 bus system showed that the control strategy could better eliminate the unbalanced power caused by the prediction error and obviously improve the voltage of sensitive loads in the real-time stage on the premise of maintaining economic optimality.

scholarly journals Demodulation of Three-Phase AC Power Transients in the Presence of Harmonic Distortion

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2341
Author(s):  
Benjamin T. Gwynn ◽  
Raymond de Callafon
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Reactive Power ◽  
Harmonic Distortion ◽  
Transient Effects ◽  
Active And Reactive Power ◽  
Reactive Power Flow ◽  
Ac Power ◽  
Rlc Circuit ◽  
Smart Inverters

Load switches in power systems may cause oscillations in active and reactive power flow. Such oscillations can be damped by synthetic inertia provided by smart inverters providing power from DC sources such as photovoltaic or battery storage. However, AC current provided by inverters is inherently non-sinusoidal, making measurements of active and reactive power subject to harmonic distortion. As a result, transient effects due to load switching can be obscured by harmonic distortion. An RLC circuit serves as a reference load. The oscillation caused by switching in the load presents as a dual-sideband suppressed-carrier signal. The carrier frequency is available via voltage data but the phase is not. Given a group of candidate signals formed from phase voltages, an algorithm based on Costas Loop that can quickly quantify the phase difference between each candidate and carrier (thus identifying the best signal for demodulation) is presented. Algorithm functionality is demonstrated in the presence of inverter-induced distortion.

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