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A centralized reactive power compensation system is proposed for low voltage (LV) distribution networks. It can be connected with any bus which needs reactive power. The current industry practice is to locally install reactive power compensation system to maintain the local bus voltage and power factor. By centralizing capacitor banks together, it can help to maintain bus voltages and power factors...
The DC power flow model is in widespread utilization in electricity-market applications and contingency analysis. The presented versions of this model can be classified into two categories: state-dependent, or Hot-Start, models and state-independent, or Cold-Start, models. A reasonable accuracy is reported in the literature regarding Hot-Start models as they take into account branch losses and bus...
This paper proposes a new Coordinated Voltage Control (CVC) method with Reactive Power Management Scheme (RPMS) for a Hybrid Micro-grid (MG). The CVC scheme, based on synchronizing the response speeds of different voltage regulating devices, is coordinated with a novel Reactive Power Management Scheme (RPMS). Two cases, with and without proposed CVC, were simulated in the PSCAD/EMTDC environment and...
This paper studies the feasibility of utilizing the reactive power of grid-connected variable-speed wind generators to enhance the steady-state voltage stability margin of the system. Allowing wind generators to work at maximum reactive power limit may cause the system to operate near the steady-state stability limit, which is undesirable. This necessitates proper coordination of reactive power output...
The task of autonomous power sharing in a micro-grid is usually achieved by decentralized droop control on individual interface power converters, which may suffer from the dependence on output line impedances. Inaccurate reactive power sharing will occur under strongly non-uniform line impedances. Due to inherently distributed and heterogeneous nature of the micro-grid, it becomes an ideal platform...
Decentralized methods for computing optimal real and reactive power setpoints for residential photovoltaic (PV) inverters are developed in this paper. It is known that conventional PV inverter controllers, which are designed to extract maximum power at unity power factor, cannot address secondary performance objectives such as voltage regulation and network loss minimization. Optimal power flow techniques...
This paper describes the droop control method for parallel operation of distributed electric springs for stabilizing ac power grid. It provides a methodology that has the potential of allowing reactive power controllers to work in different locations of the distribution lines of an ac power supply and for these reactive power controllers to support and stabilize the ac mains voltage levels at their...
Power system voltage control has traditionally been the responsibility of transmission-connected reactive power resources. Accordingly, high penetration levels of distributed generation present new challenges for reactive power management. Simply stipulating voltage control operation for distributed generators will not generally deliver voltage-responsive reactive power flows at the transmission system...
Distribution microgrids are being challenged by reverse power flows and voltage fluctuations due to renewable generation, demand response, and electric vehicles. Advances in photovoltaic (PV) inverters offer new opportunities for reactive power management provided PV owners have the right investment incentives. In this context, reactive power compensation is considered here as an ancillary service...
Grid integration of distributed energy resources (DERs) is increasing rapidly. Furthermore, smart grid technologies are making the grid more bi-directional providing opportunities to consumers to supply power back to the grid. Energy storage technologies like battery and ultracapacitor (UCAP) can be integrated through grid tied-inverters to support variable DERs such as solar and wind. In these cases,...
Generation connected to electrical distribution systems requires reliable and timely detection of loss of-mains (islanding). Passive loss of mains detection relays typically use measurements of parameters such as frequency, phase, and the magnitudes of voltage and current. If a part of the power network becomes islanded and there is a very close match between generation and demand of both active and...
This paper provides recommendations for volt-VAr and voltage ride-through needs from distributed energy resources (DERs) to contain fault induced delayed voltage recoveries (FIDVRs) events and help stabilize the grid. FIDVR events can potentially cause chain reactions and destabilize the grid. Additionally, it will provide typical residential air conditioner (RAC) unit performance during voltage transients...
Load growth along a 349 km single radial 138 kV transmission system in BC, Canada comprises many induction motors in the order of 4 MW: over ten to be directly connected, and the others fed via Variable Frequency Drives (VFDs). Dynamic simulations shows a normally cleared fault in the transmission network that supplies the radial system causes the directly connected motors to stall, resulting in sustained...
Line-Commutated Converter (LCC) based HVDC lines are widely used to transmit electric power and interconnect asynchronous AC systems. Due to the characteristic of LCC-based HVDC, large amount of reactive power consumed by HVDC potentially deteriorates system voltage stability. Reactive power control is crucial to alleviate adverse impacts of HVDC reactive power consumption from AC network and secure...
This paper introduces an exact and efficient method for computing and visualizing the power flow feasibility boundary of large networks composed of (1) saddle-node bifurcation manifolds where the Jacobian is singular and (2) limit-induced bifurcation manifolds where the network loses structural stability as the limit is encountered. This method is applied to the DTE/ITC system in Eastern Michigan...
Reactive power planning or VAR planning is critical to ensure acceptable power quality and system robustness. While addressing var planning, the key issue is optimal allocation i.e. location and size of reactive power sources. Security of power systems is a major concern during contingencies. So, consideration of all plausible contingencies during planning process is important. However, consideration...
This paper proposes an algorithm for the capacity constrained management of Distributed Energy Resources in unbalanced distribution network. The algorithm is based on linear constraints being generated from a linear approximation of the functional relationship between control variables and constrained operational variables. To eliminate the incurred linearization error, the proposed algorithm is performed...
Energy resources management is an important topic in the context of Smart Grids (SG) and MicroGrids (MG). Virtual Power Players (VPP) emerge as aggregator entities responsible for managing energy resources in SG and MG. In this paper modern meta-heuristics are compared with their hybrid version that uses a deterministic method as initial solution. The meta-heuristics implemented are Differential Search...
This paper presents the analysis of a distribution system subject to reconfiguration with high wind penetration over a period of 24 hours. In order to meet this objective, the reconfiguration problem is solved through mixed integer linear programming considering the stochasticity of the variables, where the balance between load and generation has to be satisfied at the lowest cost in each period....
High Side Voltage Control (HSVC) is a well-known method used in modern power systems. Proper HSVC droop setting can improve the voltage profiles and balance the reactive power distribution among generators. In this paper, an optimal HSVC droop planning strategy is proposed to improve voltage profile. We use monthly historical instrumentation data from SCADA to plan for the coming year monthly HSVC...
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