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For a unified power flow controller (UPFC) operated in constant power-flow control mode, a novel control scheme of bus voltage regulation is presented. The voltage magnitudes of the ac buses are monitored in real-time operation and are controlled within their limits by the adjustment of the reactive power setting of the series converter. Firstly, the sensitivity of the voltage magnitudes of ac buses...
An improved hybrid unified power flow controller (IHUPFC) is developed in this paper to increase the utilization rate of transmission line and enhance the transmission capacity in extra-high voltage (EHV) and ultra-high voltage (UHV) grid. Based on introducing the existing power flow controllers, the advantages of IHUPFC in structure and performance are analyzed. The proposed IHUPFC is composed of...
DC microgrid has been drawing much attention in recent years. In DC microgrid, introduction of renewable energies to demand sides possibly causes power imbalance and reverse power flows on feeders. These problems cause increase of distribution losses and voltage rises in feeders. To overcome these problems, a power flow control method among multiple DC feeders (nodes) is required. We have studied...
Constructing multi-terminal high voltage dc (HVDC) systems can effectively make it possible for the large-scale new energy to be integrated into the grid and make up the defects of the existing ac power system. When constructing the multi-terminal dc system, one cannot avoid the problem that how to control the dc power flow effectively. When nodes are increased and structure of dc grids becomes more...
With the development of a hybrid system, flexible AC transmission system (FACTS) and high voltage direct current (HVDC) system are using to provide the control technique in the hybrid power system. In distributed power generation systems, the DC networks have more importance to handle the problem related to the DC power flow control in DC networks. Interline Power Flow Controller (IPFC) is a FACTS...
This paper proposed the reconfigured unified power flow controller (RUPFC) design with the cascaded H-bridge converter to realize the transferability between the converter branches of shunt and series. An improved recurrent fuzzy neural network (IRFNN) was used to improve the interaction performance of real and reactive power. The flow control for the RUPFC is formed for the series converter. The...
One of the most widely used flexible ac transmission systems (FACTS) devices is unified power flow controller (UPFC) to increase the transmission capacity and enhancement of the power system stability. The effect of the UPFC in electrical power system for power flow control is presented in this paper. Phasor model of UPFC is used. All the simulations for this work have been carried out using MATLAB/SIMULINK...
This paper proposes a single-phase UPFC topology using an autotransformer structure. The proposed topology uses a N:1 transformer, which is connected as an autotransformer and a power converter module which consists of a single-phase half-bridge converter and an inverter. Also, the three-phase system can be comprised of three single-phase UPFCs. In three-phase system, while the conventional UPFC topology...
Possibility of decreasing energy losses, caused by mutual influence of nonuniform electric grids, operating in parallel, by means of introduction of phase shift transformer in previously determined optimal branch of the grid and usage of its optimal angle for current operation mode is proved on the example of 230/6 kV electric gride. It is also proved that the application of phase shift transformer...
World is moving to adopt the renewable energy sources to overcome the power issues with zero toxic emission. The key problem is to inject huge power to the grid, generating from renewable energy sources with traditional electrical equipment and grid infrastructure. Currently, work on DC networks is achieving great attention in distributed power generation system, which arise the problem related to...
This paper proposes a simplified modeling for HVDC in Newton Raphson (NR) load flow algorithm based on power injection approach. In this modeling, the HVDC is represented as injected loads at their end terminals. This injected loads are updated during the iterative process as a function of the desired power flow through the HVDC connected transmission line. The main advantages of this model are avoiding...
To increase the power flow through an existing AC line, different compensator devices are used. Flexible alternating current transmission system (FACTS) are very common for the enhancement of power transmission capability of the line. Due to stability reasons, these compensation methods have limitations. Another alternative is to construct new AC transmission lines, which is not only expensive, but...
Single Wire Earth Return (SWER) systems with long transmission line were introduced as one of the low cost options for remote electrification. Long transmission lines and load growth in such a system make voltage regulation a concern. Four quadrants distribution STATic COMpensators (DSTATCOMs) as voltage support equipment in SWER system with ability of injecting or absorbing active and reactive power...
To overcome the drawbacks of the conventional UPFC, this work proposed and Designed a new UPFC technology that addresses these impediments. This novel technology is called the Distributed PFC (DPFC). The proposed DPFC is based on single-phase system, considering the high voltage insulation, the manufacturing cost, and the installation requirement. A hierarchy control of the DPFC system is proposed,...
A power system is becoming more complex and heavily loaded day by day. Earlier electric power systems were small and localized. Thus, Real and reactive power compensation in transmission line is essential which will improve the stability of ac system. Flexible Alternating Current Transmission System (FACTS) technology provides new opportunity to control the power and enhancing the capacity of the...
Power flow control ability of meshed high voltage direct current (HVDC) grids can be improved by inserting DC power flow controller into the grids. Based on the study of existing DC power flow controllers, this paper proposes a novel interline DC power flow controller (IDCPFC) which has the benefit of less active switching devices, simpler control, little side effect on meshed grids, no external power...
Sen Transformer (ST) emulates an impedance in series with the transmission line and, in turn, allows the active and reactive power flows to change independently, meaning as desired. Traditionally, power flow control has been attempted with the use of a phase angle regulator (PAR), which can only regulate the phase angle of the line voltage and, in turn, allows the active and reactive power flows to...
This paper discusses the impact of several operating conditions and design considerations on power balancing in a MTDC system. A five terminal MTDC system is analyzed for instantaneous power balancing and variations in DC bus voltages by considering one of the terminals in constant power mode while others in DC voltage droop control mode. The study explores how the deviations in power/voltage are...
The Power quality issues like voltage variations and current variations presented in the electrical networks are due to the consumer's utilities. Which are non — linear in nature. These non — linear loads inject increased flow of currents and reduced voltages with distortions. These voltage and current variations cause adverse effect on the consumer utilities. To overcome this problem we are using...
In this paper we are discussing about a FACTS device named as UPFC (unified power flow controller). Its special features are to control active and reactive power course in a transmission line and to adjust the voltage at the bus at which it is situated. This device gives great quality flow on power system stability; these features even more considerable and perceptive that the unified power flow controller...
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