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This paper based on the commutation mechanism of series capacitor commutated converter (CCC), the CCC is applied to UHVDC transmission system, and the mathematical model of reactive power demand of CCC inverter is established. According to the actual parameters of Jiuquan-Hunan ±800 kV UHVDC transmission project, the simulation model of CCC- UHVDC system is built by PSCAD/EMTDC simulation software...
In this paper, we conduct a data-driven experimental analysis on capacitor bank switching event at a distribution grid in Riverside, CA using data from two distribution level phasor measurement units, a.k.a, μPMUs. Of particular interest was to detect the capacitor bank switching events based on feeder-level and load-level μPMUs and thus eliminating the need to install separate sensors for the switched...
This work investigates the voltage profiles of multiple distribution feeders and unbalanced problems of interconnected feeders. To maintain the required voltage levels as per ANSI standards different conventional techniques like On-load tap changing, switched Capacitor Banks, Voltage regulators and wire works are adopted. This paper also presents some of the basics and advanced methods of feeder conditioning...
In this paper, according to the problem of improving power quality in power distribution systems, measurement and analysis of middle Egypt distribution network (MEDN) is proposed as a case study. This work is considered as a part of a research project for developing and improving Egyptian distribution networks. In this paper, the measured results (data) show that the voltage profile disturbances is...
This Paper discusses the impact of the series compensation on the voltage profile of long transmission line. It gives some recommendations and precautions for some expected scenarios of wrong operation that might be taken due to some unknown information about the line condition. Also the paper shows that, the compensation of the line should be initially determined to avoid any problem that might be...
The Conservative Power Theory (CPT) is one of the latest approaches to definitions of powers and compensation in systems with nonsinusoidal voltages and currents. It is shown in this paper that the CPT misinterprets power phenomena in electrical systems, however, and it does not create right fundamentals for the power factor improvement by reactive compensation. In particular, capacitive compensation...
Among the third world countries from Asia and Africa, power quality is one of the biggest problem still persists because unaffordable high tech solutions. Voltage control problem due to an adequate reactive power compensation and its improper control results in frequent cascade tripping of electrical supply system. In this paper efforts are made to provide a low cost solution to provide exact reactive...
With the advantage of high dielectric strength and low cost, capacitive voltage transformers (CVTs) have been applied to measure the voltage in power grid widely. Recently, CVTs own the problem of big error, insulation performance degradation and high failure rate due to the complicated environment. Secondary load is an important factor to impact CVT's accuracy by analysis. Consequently, we established...
In order to stabilize the grid frequency in case of sudden loss of power generation, an injection of real power is needed. For this, a Static Var Compensator (SVC) can be combined with ultracapacitors, forming a grid frequency stabilizer. To prove the feasibility of this novel combination, the paper shows the realization of a 1 MW class test rig for full-size modules. Single modules are tested using...
This paper presents an approach for generating simplified secondary circuit models with limited SCADA and PV micro-inverter measurement data. The proposed method is computationally efficient and can be utilized with typically available measurement data. The method is applied to models of three real U.S. utility feeders with PV micro-inverter measurements. The proposed simplified secondary circuit...
The objective of this study is to examine the cost implication and reactive power generating potential of the synchronous condenser. Universally, increase in electricity demand constitutes new issues for power generation, transmission and distribution. Synchronous condenser solutions are being initiated globally to be instrumental in the best usage of power resources and offer grid systems support...
Power factor losses represent a significant factor of power losses in both industrial and domestic units. Various methods have been devised earlier to tackle this problem. This paper aims to present an indigenous technique and method which could be used for static power factor correction. It is demonstrated in this work that phase difference between voltage and current can be determined using zero...
A 5.5W mains-powered converter-free LED driver for general lighting application is presented in this summary for the university design contest. The driver is superior to its switching converter based counterparts as it does not require any bulky and expense magnetics or electrolytic capacitors. In addition, the driver is able to significantly reduce the flicker at light output with a quasi-constant...
Permanent magnet synchronous generator (PMSG) is attractive as a power source for mobility due to its high power density and low maintenance needed. However, increase of the generator current results in the voltage drop due to the synchronous reactance. That means the generator capability including rated voltage cannot be sufficiently used in whole operating range without reactive power control. This...
Traditional voltage control in distribution networks typically aims at improving the voltage profile of a distribution feeder by controlling the voltage at the zone substation only. Though useful, this method is not enough to compensate for voltage drops across long, heavily loaded feeders. Volt/var control is one of the techniques to improve overall performance of a distribution network by utilising...
As the power quality problem getting prominent in distribution networks with small hydropower injected, which existing reactive power compensation capacitors are difficult to solve, DSTATCOM is adopted to suppress the over voltage and the fluctuation caused by hydropower in this paper. Based on MATLAB/Simulink, a model of distribution networks with small hydropower injected and a control model of...
In this paper an active power filter is presented based on a multilevel converter. The active power filter is intended to be used in domestic applications where reactive power compensation in two-phase networks is required. An innovative technique to balance the DC bus voltages of the power converter capacitors is proposed and also an estimation algorithm for those voltages is developed, allowing...
This paper presents a 95VAC-120VAC mains powered converter-free LED driver for general lighting application. A quasi-constant power control scheme is proposed to significantly reduce the low-frequency-flicker, combined with a valley fill circuit to maintain good power factor performance. The driver achieves 88.2% efficiency and 0.92 PF with only 18% flicker at 110VAC 60Hz input and does not require...
Modular multilevel converter (MMC) is a relatively new and promising topology for HVDC systems. HVDC systems should remain connected during grid faults and isolate the fault. This paper studies the dynamic performance of transformer-less MMC integrated HVDC systems during unbalanced conditions and asymmetrical grid faults. It proposes a new control technique to improve unbalanced system's performance...
The stacked multiceli converter is one of the promising breeds of multilevel converters among the other several modified configurations presented in the literature. The reduced stacked multiceli converter is the most advanced one with less number of power switches and flying capacitors leading to a reduced size and cost. This paper proposes a reduced stacked multiceli converter based STATCOM to control...
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