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... plotting, you may need to edit the plots. Some users who are more experienced with MATLAB and its plots may be used to using the “show plot tools” toggle shown in Figure 3. By default, this will switch to “Plot Browser View” (as show n in the “View” drop -down). In our case, this is ill-advised. The plots generated by the toolbox often contain a very large number of lines plotted in the figure. It is strongly advised, unless your circuit is quite small (less than 150 nodes), that you do not use this route to edit your plot. Optin g to “show plot tools” may cause MATLAB to freeze as it populates the long list of plotted items in the Plot Browser. Depending on your computer specifications, and because MATLAB defaults to using a single processor core, you may be forced to kill the MATLAB process and restart it in order to continue ...
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Citations
... In OpenDSS, a 3-phase DN load flow analysis can be solved, including unbalanced phases, DGs integration, and future smart grid applications [30]. The GridPV toolbox [31] is run in the MATLAB platform. Using these tools, the DN and solar PV system can be easily modelled. ...
... Figure 3 illustrates the interface of two toolboxes. In the GridPV toolbox, the wavelet variability model [31] is applied to convert solar radiation data, smoothening the variability to compute PV system size and density in the given area. The circuit buses of the DN are placed in latitude and longitude coordinates, with the density of the PV system representing the amount of land area. ...
High level of photovoltaic (PV) integration into the distribution network (DN) may have a negative impact in terms of voltage variations across the limits. As such thorough analysis is required to ensure voltage within limits, mainly at feeder-end buses. In this study, the PV integration problem is addressed in a more comprehensive way, considering the unbalance DN, impedance characteristic, and interaction of load against available PV output. The approach applies to both the planning and operational stage in the assessment of allowable PV hosting capacity (HC). In the planning stage, the local impedance index is computed at constant load and power factor conditions. The entire network is partitioned into areas and the most suitable area for PV integration is determined, which can allow maximum PV integration, without/minimum voltage violations. In the operation stage for allowable PV hosting capacity, further voltage analysis is performed, wherein peakness of PV output and load conditions do not match each other. Towards, voltage regulation via PV inverter, the power factor profile is adjusted as a function of PV output. The study is demonstrated for transient solar radiation, with emphasis on maintaining the voltage at feeder-end buses. The simulation is carried out on interfacing GridPV in MATLAB and OpenDSS toolbox. The proposed scheme for allowable HC and further voltage regulation in the network using PV inverter is also compared with those approaches, applying optimised and centralised placement of PVs.
... The researchers used data from typical MV distribution networks that included load details and network data, which were collected from local power supply company. The system design, simulation, and analysis were carried out using OpenDSS and MATLAB software [28]. OpenDSS is a widely used software tool for modeling distribution networks due to its flexibility, integration capabilities, longterm assessment features, state-of-the-art modeling capabilities, automation tools, and strong community support. ...
... To calculate power flow in OpenDSS, we first needed to create a power distribution network model using the scripting language of OpenDSS. Next, we needed to define the load flow parameters as discussed in [28]. In a more specific context, MATLAB controls OpenDSS by utilizing a Component Object Model (COM) interface. ...
... Appendix A shows the step-by-step code for calculating the load flow, power losses, and fault analysis. load flow parameters as discussed in [28]. In a more specific context, MATLAB controls OpenDSS by utilizing a Component Object Model (COM) interface. ...
Solar photovoltaic (PV) power, a highly promising renewable energy source, encounters challenges when integrated into smart grids. These challenges encompass voltage fluctuations, issues with voltage balance, and concerns related to power quality. This study aims to comprehensively analyze the implications of solar PV penetration in Malaysian power distribution networks predominantly found in urban and rural areas. To achieve this, we employed the OpenDSS 2022 and MATLAB 2022b software tools to conduct static power flow analyses, enabling us to assess the effects of solar PV integration over a wide area under two worst-case scenarios: peak-load and no-load periods. Our investigation considered voltage violations, power losses, and fault analysis relative to the power demand of each scenario, facilitating a comprehensive evaluation of the impacts. The findings of our study revealed crucial insights. We determined that the maximum allowable power for both urban and rural networks during no-load and peak-load situations is approximately 0.5 MW and 0.125 MW, respectively. Moreover, as the percentage of PV penetration increases, notable reductions in power losses are observed, indicating the potential benefits of higher smart grid PV integration.
... In OpenDSS, a 3-phase DN load fow analysis can be solved, including unbalanced phases, DGs integration, and future smart grid applications [21]. Te GridPV toolbox [22] is run on the MATLAB platform. Using these tools, the DN and solar PV systems can be easily modeled. ...
Integration of large-scale distributed photovoltaic (PV) generation resources can lead to technical challenges, particularly voltage rise caused by PVs power injection at the time of high solar radiation profile and low load demand. Reactive power control of PV inverters can help mitigate the voltage rise, which arises just for a short duration due to high incident solar radiation. There is a possibility to control functions on these PV inverters based on the rating of the PV inverter. For one-second resolution, local data-driven voltage sensitivity estimation is applied to update the control functions such as volt-var and volt-watt on the PV inverters so as to regulate the bus voltage. Different forms of solar radiation profiles, transient varying, smooth varying, and worst operating scenario corresponding to the minimum load at the time of high PV generation, are included. The study is demonstrated for different PV penetration levels. The voltage analysis on buses is performed using power hardware (PV emulator) in the loop simulation, at one of the buses in the network, while the remaining PVs are being controlled using volt-var control (VVC)/volt-watt control (VWC) methods. The applied approach confirms to maintaining bus voltage within limits even against a very short transient time instant of solar radiation profile.
... The feeders serve nearly 6,000 customers and have more than 13,000 buses in total. The topology of the system plotted using the GridPV tool [44] is shown in Fig. 4. In this system, the substation transformer is equipped with a load tap changer (LTC). Additionally, there are 13 switched capacitor banks, each rated for 1.2 MVAR, for voltage regulation and reactive power management. ...
Reliable and resilient grid operations with high penetration levels of distributed energy resources (DERs) can be achieved with improved situational awareness and seamless integration of DERs with utility enterprise controls. This paper presents the details of the development of a data-enhanced hierarchical control (DEHC) architecture and the results of its evaluation. The DEHC is a hybrid control framework that enables the efficient, reliable, and secure operation of distribution grids with extremely high penetrations of solar photovoltaic (PV) generation by seamlessly integrating centralized utility controls, distributed controls for DERs, and autonomous grid-edge controls. In the DEHC architecture, the advanced distribution management system (ADMS) controls the legacy devices (such as load tap changers and capacitor banks), the PV smart inverters are dispatched by real-time optimal power flow, and the grid-edge devices regulate local voltages in coordination with each other. The DEHC is demonstrated using a commercial ADMS platform, real utility distribution feeder models, and grid-edge devices. The performance of the DEHC architecture is evaluated using simulations and hardware-in-the-loop experiments with voltage regulation as the control objective. The results show that the DEHC enables high penetration levels of PV in distribution feeders by effectively managing system voltages through the synergistic operation of ADMS, distributed PV smart inverter controls, and secondary-level grid-edge device control.
... Plot of EPRI Circuit 5 using GridPV[13]. ...
High penetration of distributed energy resources presents challenges for monitoring and control of power distribution systems. Some of these problems might be solved through accurate monitoring of distribution systems, such as what can be achieved with distribution system state estimation (DSSE). With the recent large-scale deployment of advanced metering infrastructure associated with existing SCADA measurements, DSSE may become a reality in many utilities. In this paper, we present a sensitivity analysis of DSSE with respect to phase mislabeling of single-phase service transformers, another class of errors distribution system operators are faced with regularly. The results show DSSE is more robust to phase label errors than a power flow-based technique, which would allow distribution engineers to more accurately capture the impacts and benefits of distributed PV. Keywords-bad data processing, distribution system calibration, distribution system state estimation, phase label error.
... The simulation circuit is a 12 kV distribution feeder of a utility. The one-line diagram is plotted in Figure 19 using GridPV tool [20]. This feeder is served by a 25 MVA, 69/12 kV, wye-wye connected substation transformer. ...
The capability of routing power from one phase to another, interphase power flow (IPPF) control, has the potential to improve power systems efficiency, stability, and operation. To date, existing works on IPPF control focus on unbalanced compensation using three-phase devices. An IPPF model is proposed for capturing the general power flow caused by single-phase elements. The model reveals that the presence of a power quantity in line-to-line single-phase elements causes an IPPF of the opposite quantity; line-to-line reactive power consumption causes real power flow from leading to lagging phase while real power consumption causes reactive power flow from lagging to leading phase. Based on the model, the IPPF control is proposed for line-to-line single-phase power electronic interfaces and static var compensators (SVCs). In addition, the control is also applicable for the line-to-neutral single-phase elements connected at the wye side of delta-wye transformers. Two simulations on a multimicrogrid system and a utility feeder are provided for verification and demonstration. The application of IPPF control allows single-phase elements to route active power between phases, improving system operation and flexibility. A simple IPPF control for active power balancing at the feeder head shows reductions in both voltage unbalances and system losses.
... The GridPV toolbox was used in this project to drive OpenDSS from MATLAB and accelerate the modeling. The toolbox was also used for data visualization [7]. ...
... The temporally parallelized QSTS simulations on all computers were set up using the GridPV toolbox [16] in MATLAB R2018b and were run in OpenDSS version 8.5.9.1 (64-bit build) [17]. This version of OpenDSS has built-in capability for running parallel QSTS simulations, based on an actor model [18]. ...
Quasi-static time-series (QSTS) analysis of distribution systems can provide critical information about the potential impacts of high penetrations of distributed and renewable resources, like solar photovoltaic systems. However, running high-resolution yearlong QSTS simulations of large distribution feeders can be prohibitively burdensome due to long computation times. Temporal parallelization of QSTS simulations is one possible solution to overcome this obstacle. QSTS simulations can be divided into multiple sections, e.g. into four equal parts of the year, and solved simultaneously with parallel computing. The challenge is that each time the simulation is divided, error is introduced. This paper presents various initialization methods for reducing the error associated with temporal parallelization of QSTS simulations and characterizes performance across multiple distribution circuits and several different computers with varying architectures.
... The solution converges within 30 second on average for each time step, which is much faster compared to the reported time of 5 minutes in [53] when solving a similar problem in an unbalanced system with only 101 buses and 34 PVs using the SQP solver in MATLAB. In addition, it should be noted that the Figure 5.13: Unbalanced system EPRI Circuit 5 (3,437 nodes) with 500 additional PVs, plotted using GridPV tool [3]. ...
... 3shows the single-line equivalent power-flow model of a converter station in multi ...
The rapid load growth coupled with large-scale renewable generation
sources remote from population centers demands future transmission grids to carry larger amounts of bulk power. For long distance transmission, highvoltage direct current (HVdc) technology is superior to the conventional 50/60-Hz high-voltage alternating current (HVac) approach. Unfortunately, the lack of dc circuit breakers limits the application of HVdc technology to point-topoint transmission links only. Thanks to advances in semiconductor materials and control methods, modern power converters make low-frequency HVac
(LF-HVac) transmission systems possible. This new method of bulk power transmission overcomes the challenges in forming practical HVdc grids. Similarly, future distribution systems are expected to accommodate growing load demand in addition to increasing number of local inverter-based photovoltaic (PV) generations.
Based on the aforementioned motivation, the objective of this dissertation is to develop power flow (PF) and optimal power flow (OPF) analysis methods for planning and operation of multi-frequency transmission systems that inherently employ a large number of converters. Similar steady-state analysis for a future distribution grid with high PV penetration, either as a standalone system or in coupling to a transmission grid, defines the second subject of the presented work.
LF-HVac transmission scheme is recently proposed for long-distance bulk-power transmission by reducing the operating ac frequency to a low and variable value as determined by operational objectives and constraints. A multi-frequency HVac - HVdc system is formed by interconnecting conventional 50/60-Hz HVac grids to LF-HVac grids and HVdc lines. With respect to the first and major focus of this dissertation, a novel concept of an LFHVac grid employing converters with a centralized control is proposed. In addition, PF and OPF in a multi-frequency HVac - HVdc system are formulated by completely representing the steady-state models of HVac, HVdc, and LF-HVac grids as well as power converters, subject to all planning and operational constraints. The PF and OPF problems are solved by efficient algorithms based on the Newton-Raphson and predictor-corrector primal-dual interior-point methods (PCPDIPM), respectively. The proposed approach is applicable for a multi-frequency power system having arbitrary numbers of buses and topologies. Based on the PF results, the dependence of system MW losses on converter dispatch as well as the operating voltage and frequency in an LF-HVac is discussed and compared to that in HVdc transmission. On the other hand, the OPF analysis is applied to determine a suitable rated voltage in planning phase as well as optimal real-time operating frequency and dispatch of generators, shunt capacitors, and converters in operation phase.
At the distribution side, high PV penetration might introduce voltage violations and reverse power flow. Besides the primary function of providing local generation, inverter-based PVs operating in grid-supporting mode can mitigate these consequences and minimize total losses with suitable dispatch. Therefore, the second focus of this work is to propose an exact OPF formulation and PCPDIPM-based solution algorithm to determine real-time dispatch of all inverters, switched capacitors, and voltage regulators with tap changers. The objective is to minimize total system losses, PV curtailment, and
operations of capacitors and voltage regulators, in addition to elimination of voltage violations and reverse power flow. Effective computational strategies are proposed to allow real-time applications of the solution approach with a large number of constraints and variables. The accuracy and quality of the numerical solution in improving system performance are validated using practical distribution circuits with 15-minute load and PV data.
High PV penetration also makes distribution systems more active and increases their impacts on the upstream transmission grids. As an extension of the work in distribution systems, a PF formulation as well as unified and sequential solution algorithms for joint transmission and distribution systems are proposed, considering their physical coupling at substations. The potential effects of distributed PVs on transmission performance are also investigated.
... The one-line diagram of the Circuit 5, plotted using Sandia GridPV tool [9], is shown in Fig. 1. This circuit has a 115/12.47 ...
In this paper, a two-stage optimization framework is proposed for optimal placement and centralized real-time control of low-voltage static var compensators (LV-SVCs) in unbalanced distribution circuits to achieve feeder level benefits namely voltage regulation and energy loss minimization. The number, locations, and the optimal real-time reactive power injections from the LV-SVCs are determined from a proposed three-phase unbalanced AC optimal power flow (ACOPF). The ACOPF is formulated as a multi-objective optimization with operating constraints written in rectangular coordinates. The resulting nonlinear nonconvex problem is solved using the predictor-corrector primal-dual interior point method (PCPDIPM). The proposed approach is scalable for application to large distribution circuits, treats the constraints of physical space limitations effectively, and can take advantage of communication capabilities of LV-SVCs for centralized real-time control. The benefits of the proposed real-time control of LV-SVCs as compared to their operation with local autonomous voltage-based distributed control is demonstrated. The results show that, the proposed approach addresses the LV-SVC placement and control problem effectively to minimize energy losses while maintaining the voltage regulation.
