scholarly journals State Estimation-Based Distributed Energy Resource Optimization for Distribution Voltage Regulation in Telemetry-Sparse Environments Using a Real-Time Digital Twin

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 774
Author(s):  
Rachid Darbali-Zamora ◽  
Jay Johnson ◽  
Adam Summers ◽  
C. Birk Jones ◽  
Clifford Hansen ◽  
...  
Keyword(s):  
State Estimation ◽  
Real Time ◽  
Distribution System ◽  
Reactive Power ◽  
Energy Resource ◽  
Field Measurements ◽  
Voltage Regulation ◽  
Distributed Energy ◽  
Pv System ◽  
Digital Twin

Real-time state estimation using a digital twin can overcome the lack of in-field measurements inside an electric feeder to optimize grid services provided by distributed energy resources (DERs). Optimal reactive power control of DERs can be used to mitigate distribution system voltage violations caused by increased penetrations of photovoltaic (PV) systems. In this work, a new technology called the Programmable Distribution Resource Open Management Optimization System (ProDROMOS) issued optimized DER reactive power setpoints based-on results from a particle swarm optimization (PSO) algorithm wrapped around OpenDSS time-series feeder simulations. This paper demonstrates the use of the ProDROMOS in a RT simulated environment using a power hardware-in-the-loop PV inverter and in a field demonstration, using a 678 kW PV system in Grafton (MA, USA). The primary contribution of the work is demonstrating a RT digital twin effectively provides state estimation pseudo-measurements that can be used to optimize DER operations for distribution voltage regulation.

scholarly journals Reactive Power Compensation with PV Inverters for System Loss Reduction

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4062 ◽  
Author(s):  
Vlahinić ◽  
Franković ◽  
Komen ◽  
Antonić
Keyword(s):  
Distribution System ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Active Power ◽  
Operating Conditions ◽  
Positive Energy ◽  
Loss Reduction ◽  
Pv System ◽  
Pv Penetration ◽  
Power Provisioning

Photovoltaic (PV) system inverters usually operate at unitary power factor, injecting only active power into the system. Recently, many studies have been done analyzing potential benefits of reactive power provisioning, such as voltage regulation, congestion mitigation and loss reduction. This article analyzes possibilities for loss reduction in a typical medium voltage distribution system. Losses in the system are compared to the losses in the PV inverters. Different load conditions and PV penetration levels are considered and for each scenario various active power generation by PV inverters are taken into account, together with allowable levels of reactive power provisioning. As far as loss reduction is considered, there is very small number of PV inverters operating conditions for which positive energy balance exists. For low and medium load levels, there is no practical possibility for loss reduction. For high loading levels and higher PV penetration specific reactive savings, due to reactive power provisioning, increase and become bigger than additional losses in PV inverters, but for a very limited range of power factors.

scholarly journals A Comparison of DER Voltage Regulation Technologies Using Real-Time Simulations

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3562 ◽  
Author(s):  
Adam Summers ◽  
Jay Johnson ◽  
Rachid Darbali-Zamora ◽  
Clifford Hansen ◽  
Jithendar Anandan ◽  
...  
Keyword(s):  
Real Time ◽  
Distribution System ◽  
Reactive Power ◽  
Optimal Solution ◽  
Operating Mode ◽  
Voltage Regulation ◽  
Global Optimum ◽  
Voltage Profile ◽  
Grid Operators ◽  
Real Time Simulations

Grid operators are now considering using distributed energy resources (DERs) to provide distribution voltage regulation rather than installing costly voltage regulation hardware. DER devices include multiple adjustable reactive power control functions, so grid operators have the difficult decision of selecting the best operating mode and settings for the DER. In this work, we develop a novel state estimation-based particle swarm optimization (PSO) for distribution voltage regulation using DER-reactive power setpoints and establish a methodology to validate and compare it against alternative DER control technologies (volt–VAR (VV), extremum seeking control (ESC)) in increasingly higher fidelity environments. Distribution system real-time simulations with virtualized and power hardware-in-the-loop (PHIL)-interfaced DER equipment were run to evaluate the implementations and select the best voltage regulation technique. Each method improved the distribution system voltage profile; VV did not reach the global optimum but the PSO and ESC methods optimized the reactive power contributions of multiple DER devices to approach the optimal solution.

scholarly journals Full-Observable Three-Phase State Estimation Algorithm Applied to Electric Distribution Grids

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1327 ◽  
Author(s):  
Thiago Soares ◽  
Ubiratan Bezerra ◽  
Maria Tostes
Keyword(s):  
State Estimation ◽  
Real Time ◽  
Distribution Systems ◽  
Phase State ◽  
Reactive Power ◽  
Estimation Algorithm ◽  
Load Flow ◽  
Electrical Network ◽  
The Real ◽  
Three Phase

This paper proposes the development of a three-phase state estimation algorithm, which ensures complete observability for the electric network and a low investment cost for application in typical electric power distribution systems, which usually exhibit low levels of supervision facilities and measurement redundancy. Using the customers´ energy bills to calculate average demands, a three-phase load flow algorithm is run to generate pseudo-measurements of voltage magnitudes, active and reactive power injections, as well as current injections which are used to ensure the electrical network is full-observable, even with measurements available at only one point, the substation-feeder coupling point. The estimation process begins with a load flow solution for the customers´ average demand and uses an adjustment mechanism to track the real-time operating state to calculate the pseudo-measurements successively. Besides estimating the real-time operation state the proposed methodology also generates nontechnical losses estimation for each operation state. The effectiveness of the state estimation procedure is demonstrated by simulation results obtained for the IEEE 13-bus test network and for a real urban feeder.

scholarly journals Local Market for TSO and DSO Reactive Power Provision Using DSO Grid Resources

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3442
Author(s):  
Fábio Retorta ◽  
João Aguiar ◽  
Igor Rezende ◽  
José Villar ◽  
Bernardo Silva
Keyword(s):  
Real Time ◽  
Distribution System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Time Interval ◽  
Local Market ◽  
Distribution Grid ◽  
Power Profile ◽  
System Operator

This paper proposes a near to real-time local market to provide reactive power to the transmission system operator (TSO), using the resources connected to a distribution grid managed by a distribution system operator (DSO). The TSO publishes a requested reactive power profile at the TSO-DSO interface for each time-interval of the next delivery period, so that market agents (managing resources of the distribution grid) can prepare and send their bids accordingly. DSO resources are the first to be mobilized, and the remaining residual reactive power is supplied by the reactive power flexibility offered in the local reactive market. Complex bids (with non-curtailability conditions) are supported to provide flexible ways of bidding fewer flexible assets (such as capacitor banks). An alternating current (AC) optimal power flow (OPF) is used to clear the bids by maximizing the social welfare to supply the TSO required reactive power profile, subject to the DSO grid constraints. A rolling window mechanism allows a continuous dispatching of reactive power, and the possibility of adapting assigned schedules to real time constraints. A simplified TSO-DSO cost assignment of the flexible reactive power used is proposed to share for settlement purposes.

Effect of Distributed Generation on Voltage Levels in a Radial Distribution Network Without Communication

2009 ◽  
Author(s):  
Allie E. Auld ◽  
Jack Brouwer ◽  
Scott Samuelsen ◽  
Keyue M. Smedley
Keyword(s):  
Distributed Generation ◽  
Radial Distribution ◽  
Power Factor ◽  
Distribution System ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Load Drop ◽  
Unity Power Factor ◽  
Distribution Feeder ◽  
Circuit Power

The challenges associated with incorporating a large amount of distributed generation (DG), including fuel cells, into a radial distribution feeder are examined using a Matlab/Simulink™ model. Two generic distribution feeder models are used to investigate possible scenarios where voltage problems may occur. Modern inverter topologies make ancillary features, such as on-demand reactive power generation/consumption economical to include, which expands the design space across which DG can function in the distribution system. The simulation platform enables testing of the following local control goals: DG connected with unity power factor, DG and load connected with unity power factor, DG connected with local voltage regulation (LVR), and DG connected with real power curtailment. Both the LVR and curtailment strategies can regulate the voltage of the simplest circuit case, but the circuit utilizing a substation with load drop compensation has no universal solution. Even DG with a penetration level around 10% of rated circuit power can cause overvoltage problems with load drop compensation. This implies that some degree of communication will be needed to reliably install a large amount of DG on a distribution circuit.

scholarly journals Model-Free Dynamic Voltage Control of Distributed Energy Resource (DER)-Based Microgrids

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3838
Author(s):  
Kenan Hatipoglu ◽  
Mohammed Olama ◽  
Yaosuo Xue
Keyword(s):  
Voltage Stability ◽  
Reactive Power ◽  
Energy Resource ◽  
Control Technique ◽  
Computational Time ◽  
Voltage Stabilizer ◽  
Distributed Energy ◽  
Model Free ◽  
Dynamic Voltage ◽  
Dynamic Voltage Stability

In this paper, we present a new control technique for sustaining dynamic voltage stability by effective reactive power control and coordination of distributed energy resources (DERs) in microgrids. The proposed control technique is based on model-free control (MFC), which has shown successful operation and improved performance in different domains and applications. This paper presents its first use in the voltage stability of a microgrid setting employing multiple synchronous generator (SG)-based and power electronic (PE)-based DERs. MFC is a computationally efficient, data-driven control technique that does not require modelling of the different components and disturbances in the power system. It is utilized as an online controller to achieve the dynamic voltage stability of a microgrid system under different disturbances and fault conditions. A 21-bus microgrid system fed by multiple DERs is considered as a case study and the overall dynamic voltage stability is investigated using time-domain dynamic simulations. Numerical results show that the proposed MFC provides improvements on the dynamic load bus voltage profiles and requires less computational time as compared to the traditional enhanced microgrid voltage stabilizer (EMGVS) scheme. Due to its simplicity and low computational requirement, MFC can be easily implemented in resource-constrained computing devices such as smart inverters.

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