The foremost objective is augmenting the ATC from source (generating) zone to sink (accepting) zone in an uncontrolled abode system utilizing uninterrupted Flow of Power technique in usual and unpredictable occasions with flawless position and regulate parameters of Devices of FACTS of a kind that SVC or TCSC on IEEE14-bus and IEEE 24-bus reliability check system. TCSC or SVC Regulating and Location parameter is measured via the utilization of RGA. ATC is reliant on numerous factors for example system working base case, network configurations, system working limits, description of contingency etc. Due to restrict on ATC, it has lesser influence on transmission system uses when compared to FACTS technology. Therefore, extreme prevailing transmission resource use would be extra worth for operators of transmission system (TSO) and consumers will get best assistance with minimized expenditure.
The UPFC can provide simultaneous control of all basic power system parameters (transmission voltage, impedance and phase angle). The controller can fulfill functions of reactive shunt compensation, series compensation and phase shifting, meeting multiple control objectives. From a functional perspective, the objectives are met by applying a DC capacitor, shunt connected transformer and voltage source converter in parallel branch and dc capacitor, voltage source convertor and series injected transformer in the series branch.
Radman and Raje presented procedure for steady state power flow calculation of power systems with multiple flexible AC transmission system (FACTS) controllers. Three FACTS controllers namely Synchronous COMpensator (STATCOM), Static Synchronous Series Compensator (SSSC), and Unified Power Flow Controller (UPFC) are studied. Newton–Raphson method of iterative solution is used for power flow equations in polar 5 coordinate. The impacts of FACTS controllers on power flow are accommodated by adding new entries and modifying some existing entries in the linearized Jacobian equation of the same system with no FACTS controllers. Santos et al. outlined a model suitable for including UPFCdevices in steady state studies. The proposed model is able to preserve the traditional Newton-Raphson technique.
optimize the overall cost involved by optimally choosing the size and the location of the UPFCdevices in the power system. UPFC can regulate the active and reactive power control as well as adaptive to voltage-magnitude control simultaneously because of its flexibility and fast control characteristics. Placement of this device in suitable location can lead to control in line flow and maintain bus voltages at desired level thereby improving the voltage stability margins.
This study aims to determine the effect of UPFC as a Flexible AC Transmission System (FACTS) tool to improve dynamic stability. FACTS is a power electronic device used for various controls on power transmission systems. Power Flow Control, Oscillation Control System can be done by FACTS device. FACTS devices using the Unified Power Flow Controller (UPFC) are modelled to see the performance of dynamic oscillations through software-assisted simulations. Dynamic oscillation occurs due to a temporary disturbance or Short Circuit, causing instability. UPFCdevices which are installed on the transmission line. Effect of UPFC to damp oscillation of power system with a model. The injection model is modelled by the active and reactive power supply equation of the injected UPFC to the transmission line. A dynamic oscillation repair is performed by regulating the shunt bus voltage of the reference value and which maintains the dc link on the capacitor voltage. Voltage, The magnitude in the shunt bus, depends on the injected reactive power, where the dc is connected to the capacitor on the UPFC device. The injection model is applied to the simulated effect of UPFC device, showing the simulated effect of UPFC mounting can improve the oscillation caused by disturbances in the power system. Speed Change Oscillations for the generator 1 dan Generator 2, the system without UPFC oscillates for Generator 1, with Over-shoot 6.5x10- 1 while using UPFC Over-shoot of 4x10-4. UPFC can reduce the speed change in Generator 1 in about 7.5 seconds; the system returns the equilibrium position (Steady-State).
The single-objective and multi-objective optimization problems are performed on IEEE 14-bus test system considering the total fuel cost, active power losses, and the system loadability as objective functions. The results of the single-objective optimization are shown in Table 2 with and without minimization of the investment cost of OUPFC and UPFCdevices. In the case without minimization of the investment cost, two devices have a similar performance with dierent sizes while the OUPFC investment cost is less than that of UPFC as much as 80%, 78%, and 81% for optimization of the total fuel cost, active power losses, and the system loadability, respectively. In the case with minimization of the investment cost, OUPFC has better performance than UPFC with 71.1% less investment cost for minimizing the total fuel cost and the investment cost, simultaneously. Also, the UPFC improves investment 2% more than OUPFC to minimize active power losses while the investment cost of UPFC is 92.8% more than that of OUPFC. The results show that utilizing both UPFC and OUPFC enhances system loadability objective function almost equally, but with 75.1% reduction in investment cost of OUPFC compared to that of UPFC.
ABSTRACT- Now a day’s FACTS devices are used to control the flow of power, to increase the transmission capacity and to improve the stability of the power system. One of the most commonly used FACTS devices is Unified Power Flow Controller (UPFC)In this paper, a modulation and control method for the new transformer less unified power flow controller (UPFC) is presented. To overcome the problems with transformers, a completely transformer less UPFC based on an innovative configuration of two cascade multilevel inverters has been proposed. The new UPFC offers several advantages over the traditional technology, such as transformer less, light weight, high efficiency, low cost and fast dynamic response. This paper focuses on the modulation and control for this new transformer less UPFC, including artificial neural networks(ANN) controlling for low total harmonic distortion and high efficiency, independent active and reactive power control over the transmission line, dc-link voltage balance control, etc. Both the steady-state and dynamic response results will be shown in this paper. UPFC on controlling the flow of power and the effectiveness of controllers on the performance of UPFC is used to simulate UPFC model and to create the ANN.
The flow chart for the proposed algorithm of ACO for optimal location and parameter setting of UPFC to enhance power system security is given in Fig 3. From figure it is evident that initially all data including bus, line UPFC parameters, constraints etc are given as input. Then for each line outage, both base case (without UPFC) and security enhanced case (with UPFC) using ACO and NLP-IP is performed to minimize the objective function (1). The results are saved and the same process is done for all transmission lines.
ABSTRACT:In this project ANN based control scheme has been proposed for a UPFC to be used as an active power filter. The objective is to guarantee power to the load at the required power quality. The ANN control unit monitors the voltage at the point of common coupling. UPFC enables improved power quality by maintaining power factor nearer to unity Rapid response time, the ability to provide reactive power at low voltage and to provide voltage compensation can be obtained. For unbalanced voltage compensation, two unbalanced controllers using the phase voltage amplitude and negative sequence component are proposed. Shunt active filter with UPFC proves to be an effective solution for active power filter applications. The system employs discrete PWM technology to provide higher Power Quality. Non- linearity in renewable power system affects power quality. By using ANN active power filter performance is enhanced. The power generation is non-uniform which affects voltage regulation and creates voltage distortion in power system. Thus the unbalance created by single phase non-linear loads and harmonic currents are effectively compensated. Using MATLAB/Simulink, simulations are carried out and output results are shown.
As per this paper display an adjustment and control method for the transformer considerably less UPFC, which has the consequent highlights: All UPFC capacities, together with voltage law, line impedance repayment, fragment exchanging or synchronous control of voltage, impedance, and area mentality, in this way accomplishing fair vivacious and responsive power float oversee over the transmission line; FFM of the CMI for to a great degree low THD of yield voltage, low exchanging misfortune and intemperate performance; Dc capacitor voltage adjusting control for both gathering and shunt CMIs; Fast unique response (<10 ms). The fluffy controller is that the pleasant relevant for the human decision making instrument, conferring the operation of AN electronic system with choices of experts. The FLC consolidates of 3 sections: fuzzification, impedance motor and defuzzification. The transformerless UPFC with proposed tweak and control might be mounted wherever in the lattice to expand/flowline power transmission over the overall matrices, diminish transmission blockage and empower high entrance of inexhaustible power assets. 7. References
ABSTRACT: In modern power systems, there is a increase in power demand continuously. To meet the change in power demand the power flow on the transmission lines are actively controlled. Power flow controlling devices are required for such purpose among all PE Power flow control devices; the Unified Power Flow Controller (UPFC) is used to control the power flow on the single transmission line and Interline power flow controller (lPFC) is used to control the power flow in the parallel transmission lines or on the multi-lines. Interline unified power flow controller (IUPFC) is a new device, which is the modified version UPFC and IPFC.
In this paper the power system stability enhancement of test network with FACTS devices TCSC, STATCOM and UPFC is presented and discussed under three phase short circuit fault. It is clear that the system regains its stability under any one of the FACTS device is involved. Also the settling time to reach the stability of the system with UPFC for different parameters (Generator Voltage – 1.4 secs, Generator Current – 2.3 secs, Generator Load Angle – 4.2 secs, Voltage near Infinite Bus – 0.2 secs and Current near Infinite Bus – 0.1 secs) is comparatively much better than STATCOM as well as TCSC.
In this paper the power system stability enhancement of test network with FACTS devices TCSC, STATCOM and UPFC is presented and discussed under three phase short circuit fault. It is clear that the system regains its stability under any one of the FACTS device is involved. Also the settling time to reach the stability of the system with UPFC for different parameters (Generator Voltage – 1.4 secs, Generator Current – 2.3 secs, Generator Load Angle – 4.2 secs, Voltage near Infinite Bus – 0.2 secs and Current near Infinite Bus – 0.1 secs) is comparatively much better than STATCOM as well as TCSC. REFERENCES
lectrical power systems in modern era are characterized by extensive system interconnections and increasing dependence on control for optimum utilization of existing resources. The supply of reliable and economic electric energy is a major determinant of industrial progress and consequent rise in the standard of living . The growth of the power systems in the future will rely on increasing the capability of existing power transmission systems rather than building the new transmission lines and the power stations for an economical and an environmental reasons. The requirement of the new power flow controllers, which is capable of increasing the transmission reliability and controlling the power flow through the predefined corridors, will certainly increase due to the deregulation of the electricity markets. Additionally, these new controllers must be regulate the voltage levels and the flow of the real and reactive power in the transmission line to use full capability of the system in some cases with no reduction in the system stability and security margins . Flexible Alternating Current Transmission Systems (FACTS) is an evolving technology based solution to help electric utilities fully utilize their transmission assets. The technology was presented in the late of 1980s . FACTS devices enhance the stability of the power system with its fast control characteristics and continuous compensating capability.
The continuing rapid development of high-power semiconductor technology now makes it possible to control electrical the systems of power by means of the devices of power electronic. These devices constitute an emerging technology called FACTS (flexible alternating current transmission systems). The technology of FACTS opens up novel chances for supervisory the both kinds of powers and enhancing the usable capacity of present transmission systems. This opportunity is arises through the ability of FACTS controllers to adjust the power system electrical parameters including series and shunt impedances, current, voltage, phase angle, and the damping oscillations etc. The implementation of such equipment’s requires the different power electronics-based compensators and controllers. The FACTS devices use various power electronics devices such as Thyristors , Gate turn offs (GTO), Insulated gate bipolar transistors (IGBT), Insulated Gate Commutated thyristors (IGCT), they can be controlled very fast as well as different control algorithms adapted to various situations. FACTS technology has a lots of benefits, such as greater power flow control ability, increased the loading of existing transmission circuits, damping of power system oscillations, has less bed impact on environmental and , has the less cost than other alternative techniques of transmission system is used.
Unified power flow controller (UPFC) is one of the most advanced FACTS devices and is a combination of STATCOM and a SSSC. UPFC was designed with two VSCs sharing a mutual capacitor on their dc side and a unified control system. The two devices are coupled through the dc link and the combination allows exchange of real power between the series SSSC and the shunt STATCOM. This controller (UPFC) has the facility to provide concurrent real and reactive series line compensation without any external electric energy source. Thus, UPFC is able to control real power flow, reactive power flow in a line, and the voltage magnitude at the UPFC terminals and may also be used as independently for shunt reactive compensation studied in[3,8].
ABSTRACT:In the present era, the quality of the power system should be more specific when it reaches customer ends. Key industrial loads need reactive power for nutritious magnetic field, for example, transformers, furnaces, induction motors etc. Reactive Power Compensation (RPC), a chief power quality issue in the distribution system, which affects the performance of the power system. The core fact behind reactive power compensation is the amplified system stability, better utilization of gadgets connected to the systems voltage regulation,dropping system losses associated with the system. The complete pillar of the compensating strategies and power electronic application in compensating devices is depicted in this paper. FACTS devices are energetic reactive power compensator capable of contributing reactive power to the grid and consuming reactive power from the grid. This paper proposes the UPFC, a FACTS device for the renumeration of reactive power. The compensation using the UPFC modeling is also discussed in this work. The UPFC normally mounted between source voltage and critical or sensitive load. The configuration of UPFC has been scheduled for improving voltage profile management and power factor performance for different sorts of loads in distribution system. UPFC is an effective degree to sustain voltage stability and improve power quality events of distribution system. The simulation is performed in MATLAB for UPFC and voltage source converter (VSC).
This paper has presented a new concept called DPFC. The DPFC emerges from the UPFC and inherits the control capability of the UPFC, which is simultaneous adjustment of the line impedance, the transmission angle, and the bus-voltage magnitude. The common dc link between the shunt and series converters, which is used for exchanging active power in the UPFC, is eliminated. This power is now transmitted through the transmission line at the third-harmonic frequency. The series converter of the DPFC employs the D-FACTS concept, which uses multiple small single-phase converters instead of one large-size converter. The reliability of the DPFC is greatly increased because of the redundancy of the series of the series converters. The total cost of the DPFC is also much lower than the UPFC, because no high-voltage isolation is required at the series-converter part and the rating of the components of is low. The DPFC concept has been verified by an experimental setup. It is proved that the shunt and series converters in the DPFC can exchange active power at the third-harmonic frequency, and the series converters are able to inject controllable active and reactive power at the fundamental frequency.
For the last few years, the focus of research in the FACTS area is mainly on UPFC. This has resulted in many useful contributions in the areas of modeling of UPFC  – , effective control strategy for UPFC ,  and the system stability enhancement using UPFC, . However, to achieve the good performance of UPFC, proper placement of UPFC is a very important task. There are several methods for finding the locations of UPFC in vertically integrated systems but little attention has been devoted to the two fold task of increasing the loadability and reducing the losses .
This paper presents a novel development of a fuzzy logic controlled power system using UPFCs to damp the oscillations in a FACTS based integrated multi-machine power system consisting of 3 generators, 3 transformers, 9 buses, 4 loads & 2 UPFCs. Oscillations in power systems have to be taken a serious note of when the fault takes place in any part of the system, else this might lead to the instability mode & shutting down of the power system. UPFC based POD controllers can be used to suppress the oscillations upon the occurrence of a fault at the generator side or near the bus side. In order to improve the dynamic performance of the multi-machine power system, the behavior of the UPFC based POD controller should be coordinated, otherwise the power system performance might be deteriorated. In order to keep the advantages of the existing POD controller and to improve the UPFC-POD performance, a hybrid fuzzy coordination based controller can be used ahead of a UPFC based POD controller to increase the system dynamical performance & to coordinate the UPFC-POD combination. This paper depicts about this hybrid combination of a fuzzy with a UPFC & POD control strategy to damp the electro-mechanical oscillations. The amplification part of the conventional controller is modified by the fuzzy coordination controller. Simulink models are developed with & without the hybrid controller. The 3 phase to ground symmetrical fault is made to occur near the first generator for 200 ms. Simulations are performed with & without the controller. The digital simulation results show the effectiveness of the method presented in this paper. Keywords : UPFC, POD, Fuzzy logic, Coordination, Controller, Oscillations, Damping, Stability,