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This work presents a methodology for segregation of transmission losses of active and reactive power flows based on load flow study with unity vs actual power factor of load buses. The proposed methodology applied on existing 12 bus Indian power system having five transmission lines, 12 power transformers, five load buses, 13 shunt capacitor banks. Hourly actual system parameters of test system, viz. active and reactive power demand, tap position of transformers, ON/OFF status of shunt capacitor banks and swing bus voltage gathered from the grid substations and simulation studies performed on MiPower software for separation of losses. In second part, bus reactive demand is mitigated through automatic switched shunt capacitor banks and its effect on system voltage profile, loading of transmission system elements, number of operations of on load tap changer and losses are presented.

This study presents a quadratic optimal reactive power flow (ORPF) models for ac-dc hybrid power system. In the ac system, the load tap changing transformer is represented by an ideal transformer and its series impedance with an artificial node located between them. The ideal transformer is further replaced by the current injections at the two terminal nodes. The artificial node voltage and the current injections are used to express the relationship between the quantities at both sides. For the dc system, some variables are introduced to formulate the dc equations. Finally, utilising their couplings, the ac and dc equations expressed in different coordinates can be integrated into a unified quadratic ac-dc ORPF model, which is simply expressed in the block form. The predictor-corrector primal-dual interior-point method is used to solve the optimisation problem. The quadratic model results in the constant Hessians that all have elements of 1 or −1, and mostly being zero and multiplication is not required to form the full Hessian, thereby accelerating the entire optimal process significantly. Extensive numerical simulations have shown the validity and superior performance of the proposed model than the conventional one.

Optimal reactive power flow (ORPF) is of great importance for the electrical reliability and economic operation of modern power systems. The integration of distributed generations (DGs) and two-terminal high voltage direct current (HVDC) systems into electrical networks has further complicated the ORPF problem. Due to the high computational complexity of the ORPF problem, a powerful and robust optimization algorithm is required to solve it. This paper proposes a powerful metaheuristic algorithm namely fitness-distance balance-based adaptive gaining-sharing knowledge (FDBAGSK). In the performance evaluation, 39 IEEE CEC benchmark functions are used to compare FDBAGSK with the original AGSK algorithm. Moreover, the proposed algorithm is applied to perform the ORPF task in modified IEEE 30- and IEEE 57-bus test systems. The effectiveness of the FDBAGSK method was tested for the optimization of three non-convex objectives: active power loss, voltage deviation and voltage stability index. The ORPF results obtained from the FDBAGSK algorithm are compared with other optimization algorithms in the literature. Given that all results are together, it has been observed that FDBAGSK is an effective method that can be used in solving global optimization and constrained real-world engineering problems.

The main emphasis in the operation of an electricity system is placed on its safe and reliable operation. The flow of reactive power in a network can affect voltage conditions in individual nodes of the transmission system. In recent years, there have been changes in the network that have resulted in increased capacitive reactive power flows from lower voltage levels to higher ones. These flows can cause the voltage to rise above the limit. This paper examines recent changes in the reactive power transmission in the network, especially at lower voltage levels. The possible impact of these changes on the flow of capacitive reactive power at higher voltage levels is analyzed. This paper also presents a description and the simulated impact of power lines at different voltage levels on reactive power flows. Real measurements of different types of consumers at the low-voltage (LV) level are analyzed. Finally, a simulation model was created to simulate the impact of a customer’s power contribution to the reactive power flows from the point of view of a 110 kV voltage node. This node is characterized as a supply point.

The loads in rustic area are preeminent pump sets used for various applications ie. lift irrigation system. Minimal power factor and minimal load factor is found in loads. Further, being a factor dissemination of loads, load density is found low. The present distribution system dwell of three-phase 11KV/433Volts distribution transformer with extended LT Lines. In this system, voltage profile and reliability are poor. In this paper, HVDS is unveiled with small capacity distribution transformers. A simple load flow technique is used for solving distribution networks before and after implementation of HVDS. The advantages of implementing HVDS against LVDS system are discussed. [PUBLICATION ABSTRACT]

Optimal power dispatch is essential to improve the power system’s safety, stability, and optimal operation. The present research proposes a multi-objective optimization methodology to solve the real and reactive power dispatch problem by minimizing the active power losses and generation costs based on mixed-integer nonlinear programming (MINLP) using the epsilon constraint method and fuzzy satisficing approach. The proposed methodology was tested on the IEEE 30-bus system, in which each objective function was modeled and simulated independently to verify the results with what is obtained via Digsilent Power Factory and then combined, which no longer allows for the simulation of Digsilent Power Factory. One of the main contributions was demonstrating that the proposed methodology is superior to the one available in Digsilent Power Factory, since this program only allows for the analysis of single-objective problems.

The concept of hybrid high-voltage alternating current (HVAC) and high-voltage direct current (HVDC) grid systems brings a massive advantage to reduce AC line loading, increased utilization of network infrastructure, and lower operational costs. However, it comes with issues, such as integration challenges, control strategies, optimization control, and security. The combined objectives in hybrid HVAC–HVDC grids are to achieve the fast regulation of DC voltage and frequency, optimal power flow, and stable operation during normal and abnormal conditions. The rise in hybrid HVAC–HVDC grids and associated issues are reviewed in this study along with state-of-the-art literature and developments that focus on modeling robust droop control, load frequency control, and DC voltage regulation techniques. The definitions, characteristics, and classifications of key issues are introduced. The paper summaries the key insights of hybrid HVAC–HVDC grids, current developments, and future research directions and prospects, which have led to the evolution of this field. Therefore, the motivation, novelty, and the main contribution of the survey is to comprehensively analyze the integration challenges, implemented control algorithms, employed optimization algorithms, and major security challenges of hybrid HVAC–HVDC systems. Moreover, future research prospects are identified, such as security algorithms’ constraints, dynamic contingency modeling, and cost-effective and reliable operation.

Power flow control has become increasingly important in recent years in the area of smart power systems that have to integrate increased shares of variable renewable energy sources. The unified power flow controller (UPFC) provides in real-time, simultaneously or selectively, active and reactive power flow control as well as voltage control in smart power systems. Several models and methods have been suggested for the control, analysis, operation, and planning of UPFCs in smart power systems. This study introduces a review of the state-of-the-art models and methods of UPFCs in smart power systems, analysing and classifying current and future research trends in this field.

Power flow calculation is the basis of power grid planning and many system analysis tasks require convergent power flow conditions. To address the unsolvable power flow problem caused by the reactive power imbalance, a method for adjusting reactive power flow convergence based on deep reinforcement learning is proposed. The deep reinforcement learning method takes switching parallel reactive compensation as the action space and sets the reward value based on the power flow convergence and reactive power adjustment. For the non-convergence power flow, the 500 kV nodes with reactive power compensation devices on the low-voltage side are converted into PV nodes by node type switching. And the quantified reactive power non-convergence index is acquired. Then, the action space and reward value of deep reinforcement learning are reasonably designed and the adjustment strategy is obtained by taking the reactive power non-convergence index as the algorithm state space. Finally, the effectiveness of the power flow convergence adjustment algorithm is verified by an actual power grid system in a province.

In this paper, we investigate the connection between average power flows in Love wave waveguides with the mass sensitivity of Love wave sensors. In fact, loading with a Newtonian liquid gives rise to two extra power flows, in the transverse direction towards the loading Newtonian liquid. The first is an active power flow feeding viscous losses in the Newtonian liquid and the second is a reactive power flow that is responsible for the phase delay of the Love wave and consequently for the changes in phase velocity of the Love wave. Since loading with a lossless mass also leads to changes in the phase velocity, we assert that mass sensitivity Sσvp of Love wave sensors is connected to the average reactive power flow, in the transverse direction x2, bouncing back and forth, between the interior of the waveguide and the loading Newtonian liquid. Subsequently, we found the thickness of the effective surface layer of mass that is equivalent to loading with a semi-infinite Newtonian liquid. The analytical formulas developed in this paper are illustrated by the results of numerical calculations performed for an exemplary Love wave waveguide composed of a PMMA surface layer deposited on an ST-Quartz substrate.