Voltage support control of unbalanced distribution systems by reactive power regulation

Nowadays, response to electricity consumption growth is mainly supported by efficiency; therefore, this is the new main goal in the development of electric distribution networks, which must fully comply with the system’s constraints. In recent decades, the issue of independent reactive power services, including the optimal placement of capacitors in the grid due to the restructuring of the electricity industry and the creation of a competitive electricity market, has received attention from related companies. In this context, a genetic algorithm is proposed for optimal planning of capacitor banks. A case study derived from a real network, considering the application of suitable daily profiles for loads and generators, to obtain a better representation of the electrical conditions, is discussed in the present paper. The results confirmed that some placement solutions can be obtained with a good compromise between costs and benefits; the adopted benefits are energy losses and power factor infringements, taking into account the network technical limits. The feasibility and effectiveness of the proposed algorithm for optimal placement and sizing of capacitor banks in distribution systems, with the definition of a suitable control pattern, have been proved.

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A Novel Adaptive Control Approach Based on Available Headroom of the VSC-HVDC for Enhancement of the AC Voltage Stability

Energies ◽

10.3390/en14113222 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3222

Author(s):

Duc Nguyen Huu

Keyword(s):

Adaptive Control ◽

Voltage Stability ◽

Reactive Power ◽

Control Method ◽

Offshore Wind ◽

Voltage Source ◽

Long Distance ◽

Control Approach ◽

Hvdc System ◽

Voltage Support

Increasing offshore wind farms are rapidly installed and planned. However, this will pose a bottle neck challenge for long-distance transmission as well as inherent variation of their generating power outputs to the existing AC grid. VSC-HVDC links could be an effective and flexible method for this issue. With the growing use of voltage source converter high-voltage direct current (VSC-HVDC) technology, the hybrid VSC-HVDC and AC system will be a next-generation transmission network. This paper analyzes the contribution of the multi VSC-HVDC system on the AC voltage stability of the hybrid system. A key contribution of this research is proposing a novel adaptive control approach of the VSC-HVDC as a so-called dynamic reactive power booster to enhance the voltage stability of the AC system. The core idea is that the novel control system is automatically providing a reactive current based on dynamic frequency of the AC system to maximal AC voltage support. Based on the analysis, an adaptive control method applied to the multi VSC-HVDC system is proposed to realize maximum capacity of VSC for reactive power according to the change of the system frequency during severe faults of the AC grid. A representative hybrid AC-DC network based on Germany is developed. Detailed modeling of the hybrid AC-DC network and its proposed control is derived in PSCAD software. PSCAD simulation results and analysis verify the effective performance of this novel adaptive control of VSC-HVDC for voltage support. Thanks to this control scheme, the hybrid AC-DC network can avoid circumstances that lead to voltage instability.

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Multi-objective optimization of optimal capacitor allocation in radial distribution systems

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2019-0206 ◽

2020 ◽

Vol 21 (3) ◽

Author(s):

Sayed Mir Shah Danish ◽

Mikaeel Ahmadi ◽

Atsushi Yona ◽

Tomonobu Senjyu ◽

Narayanan Krishna ◽

...

Keyword(s):

Radial Distribution ◽

Distribution System ◽

Distribution Systems ◽

Reactive Power ◽

Stability Index ◽

Distribution Networks ◽

Optimization Method ◽

Optimal Size ◽

Multi Objective Optimization ◽

Multi Objective

AbstractThe optimal size and location of the compensator in the distribution system play a significant role in minimizing the energy loss and the cost of reactive power compensation. This article introduces an efficient heuristic-based approach to assign static shunt capacitors along radial distribution networks using multi-objective optimization method. A new objective function different from literature is adapted to enhance the overall system voltage stability index, minimize power loss, and to achieve maximum net yearly savings. However, the capacitor sizes are assumed as discrete known variables, which are to be placed on the buses such that it reduces the losses of the distribution system to a minimum. Load sensitive factor (LSF) has been used to predict the most effective buses as the best place for installing compensator devices. IEEE 34-bus and 118-bus test distribution systems are utilized to validate and demonstrate the applicability of the proposed method. The simulation results obtained are compared with previous methods reported in the literature and found to be encouraging.

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Electric Vehicle Charging with Reactive Power Compensation to Distribution Systems

2020 IEEE Industry Applications Society Annual Meeting ◽

10.1109/ias44978.2020.9334838 ◽

2020 ◽

Author(s):

Khalil Sinjari ◽

Joydeep Mitra

Keyword(s):

Electric Vehicle ◽

Distribution Systems ◽

Reactive Power ◽

Reactive Power Compensation ◽

Electric Vehicle Charging ◽

Vehicle Charging

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

Energies ◽

10.3390/en12071327 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1327 ◽

Cited By ~ 7

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.

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