In this paper, a PowerFlow Control in transmission line with respect to voltage condition (L-G, L-L-G, L-L) over come by using unifiedpowerflowcontroller. The existing system employs UPFC with transformer less connection with both series and shunt converter. This converter have been cascaded with multilevel inverters which is more complicated to enhance the performance of UPFC.A proposed system consist of three terminal transformer for shunt converter and six terminal transformer for series converter. Shunt converter & series converter is coupled with common DC capacitor. DC link capacitor voltage is maintained using PID controller and synchronous reference frame theory (SRF) is used to generate reference voltage & current signal. Simulation studies are carried out for (L-G, L-L-G, L-L real & reactivepower compensation results will be shown in this paper).
ontrolling realpower is one of the most significant purposes in designing and running modern distribution networks. FACTS devices play a fundamental role in controlling the active power. Recently, the new technology of IPC has developed to control the active power. Generically it is a series-connected device, which its main component in each phase is a reactive or a capacitor. These elements are subjected to separately phase-shifted voltages, which are created by phase shifting transformers (PST). In  an algorithm for calculating the value of IPC elements is proposed. At [2-4], characteristics of IPC are discussed. Various models based on IPC applications in the network and phase shifting ability have been presented [5-8]. IPC has only passive elements, such as reactor, capacitor and phase shifting transformers. It is a new technology, which effectively limits fault currents and control powerflowin normal conditions.
744 fixed point theorem. The motivation of using this control strategy is flexibility of the synthesis procedure for modeling uncertainty, direct formulation of performance objectives and practical constraints. Due to its practical merit, the proposed control strategy has a decentralized scheme. The advantages of this operation philosophy are reduction in the controller complexity by reducing the system size and suitability for practical implementation which is ideally useful for the real world complex power system. The time domain linear and nonlinear simulation results show that it achieve good performance for damping low frequency oscillations and improves the transient stability under different operating conditions and disturbances. The system performance characteristics in terms of ‘ITAE’ and ‘FD’ indices reveal that the proposed method is a promising control scheme for UPFC controller design and superior these of the classical controllers. Thus, it is recommended to generate good quality and reliable electric energy in the power systems.
SINCE its first introduction, static power converter development has grown rapidly with many converter topologies now readily found in the open literature. Accompanying this development is the equally rapid identification of application areas, where power converters can contribute positively toward raising the overall system quality , . In most cases, the identified applications would require the power converters to be connected in series  or shunt , depending on the operating scenarios under consideration. In addition, they need to be programmed with voltage, current, and/or power regulation schemes so that they can smoothly compensate for harmonics, reactivepowerflow, unbalance, and voltage variations. For even more stringent regulation of supply quality, both a shunt and a series converter are added with one of them tasked to perform voltage regulation, while the other performs current regulation. Almost always, these two converters are connected in a back-to-back configuration , using 12 switches in total and sharing a common dc-link capacitor, as reflected by the configuration drawn in Fig. 1(a). Where available, a micro source can also be inserted to the common dc link, if the intention is to provide for distributed generation in a micro grid , without significantly impacting on the long proven proper functioning of the back-to-back configuration. Even though facing no major operating concerns at present, improvements through topological modification or replacement of the back-to-back configuration to reduce its losses, component count,
This paper presents modelling and simulation of a typical 33kV Distribution network for powerflow. NEPLAN software was used to achieve this. The results of this powerflow study are also presented. Because the powerflow results obtained shows that high reactivepower flows within the Distribution network, reactors are recommended to be installed in strategic locations in the Distribution Network. There is also the need to site two new 33/11kV, 15MVA Injection Substations in two locations within the distribution network, particularly between ALG-ANI and ALG-ADM Busbars, where relatively high power losses are observed as a result of the long distances of 6.84km and 6.13km respectively between the Busbars. Finally, overloaded lines within the distribution network could be taken care ofby the addition of new lines. But, for economic system operation and maximum load point reliability level,
ABSTRACT: Consistent increase in the demand for electrical energy often leads to heavy loading of transmission lines. One of the consequences of this is that such transmission systems are subjected to imbalance in the reactivepower and hence voltage instability and reduction inrealpowerof the system. Conventional methods of enhancing voltage stability and improving efficiency have proven to be slow and difficult to control. A new approach, however, is the use of Flexible AC Transmission System (FACTS) controllers. This paper applied UnifiedPowerFlowController (UPFC), a member of this class of devices to Nigeria’s 330kV transmission system using MATLAB. Obtained results showed an improvement in the voltage magnitude of bus 9 and bus 13 from 0.9896 and 0.9765 to 1.02 and 1.0199 respectively. Also, the active power loss was reduced by 2.53% from 85.177MW to 83.025MW when UPFC was applied. Incorporation of UPFC improved the system’s voltage stability and reduced active power losses. The UPFC could therefore be deployed to minimize prolonged and frequent voltage instability in transmission networks and enhance system efficiency.
Energy Development Co., Inc.), Rashmi Jawahar Ganesh (UN Environment), He Jieying (CWEA), Patrick Jochem (Institute for Industrial Production), Izabela Kielichowska (Polish Wind Energy Association), Wim Jonker Klunne (Energy & Environment Partnership), Aris Karcanias (FTI Consulting), John Keane (GOGLA), Binod Prasad Koirala (TU Delft), Karin Kritzinger (Stellenbosch University), Arun Kumar (Indian Institute of Technology, Roorkee), Bikash Kumar Sahu (Gandhi Institute for Education and Technology), Sigrid Kusch (University of Padua), Oliver Lah (Wuppertal Institute), Benoît Lebot (International Partnership for Energy Efficiency Cooperation), Debora Ley (Latinoamérica Renovable), Detlef Loy (Loy Energy Consulting), Jaideep Malaviya (Solar Thermal Federation of India), Ana Marques (ICLEI), Romain Mauger (North West University), Marcelo Mesquita (ABRASOL), Simon Müller (IEA), Julia Münch (Fachverband Biogas e.V.), Frederico Musazzi (Anima), Om Prakash Nangia (New Era Solar Solutions), Les Nelson (International Association of Plumbing and Mechanical Officials), Jan Erik Nielsen (PlanEnergi),
Inpowerflow problem there are a number of nonlinear relationships between voltage and current at each bus which must be solved for all voltages and currents such that these nonlinear relationships are met. The complexity of obtaining a formal solution for powerflowinpower system arises because of differences in the type of data specified for the different type of buses. Although the formulation of sufficient equations to match the number of unknown state variables is not difficult, the closed form of solution is not practical  .
Wind power is one of the renewable energy sources. It has various advantages like, cost competitiveness, environmentally clean and safeness. Large wind farms have stability problems when they are integrated to the power system. A thorough analysis is required to identify the stability problems and to develop measures to improve it. Mostly used wind generator is a fixed speed induction generator, which requires reactivepower to maintain air gap flux. Reactivepower equipments are used to enable recovery of large wind farms from severe system disturbances. In this paper shunt and series FACTS devices, Static Synchronous Compensator (STATCOM) and Static Synchronous Series Compensator are used for the purpose of stabilizing grid connected wind generator against the grid-side disturbances. The essential feature of the FACTS devices is their ability to absorb or inject the reactivepower. Since stability is a non linear process so system performance can be improved by using nonlinear controllers. Neurofuzzy controller (NFC) is a non linear controller. NFC has faster response than conventional PI controllers.
When the destination wants to send an ACK referring to this data packet, it reveals its ACK key; similarly, when it wants to signal that this data packet is missing, it reveals its NACK key. Now, any intermediate node that has the data packet in question can verify if the NACK is authentic by checking if the appropriate MAC verifies correctly with the given key. As only the source and the destination can produce the right keys, but the source never reveals them, the intermediate node can be sure that the control information must have been sent by the destination. Besides, intermediate nodes manage the cache following a strict FIFO policy and thus they never delete cached data packets upon reception of a NACK or ACK. Regarding end-to-end synchronization, the source only deletes data packets from its transmission window if the appropriate MAC matches the ACK keys in control packets. A side effect of the scheme is that the MAC values provide end-to-end protection, meaning that the destination can check the authenticity and integrity of each received data packet, which is also a desirable feature.
Arghandeh attempted to clarify and standardize the definition of resilience within EPGs . For this, the author carried out a study of the different terms used, and those often confused with resilience, in the literature. This study concluded that a resilient system should evaluate risks and perform a set of actions, over a period of time, to ensure its functionality against risks, attacks or faults. For the English Cabinet Office, infrastructure resilience is obtained from a good system and network design in order to ensure the needed resistance, reliability and the capability to switch or divide the system into other parts (redundancy), to maintain the continuity of services during an outage . Also, to present a good resilience, the system should acquire the ability, capacity and capability to respond and recover. For Jufri, powergrid resilience is assessed based on the amount of damage caused by an extreme event on the grid or by the capability that the grid has to keep functioning during the damaged state .
Ferreira et alli (2000) presented some simulation results for the application of the DFIM as a synchronous con- denser, controlling the voltage in a power system. The rotor voltage was directly controlled and the rotor fre- quency was kept constant. Figure 6 shows the labora- tory test rig, which was used to validate those simula- tions. The system consists of a DFIM, which is fed from the mains via a three-phase autotransformer. The in- ductors between the machine and the transformer are used to ensure that there is a voltage diﬀerence between these two terminals. The rotor is fed from a commercial inverter, which works with constant V/f ratio. As the control scheme relies on a fixed frequency/variable volt- age characteristics, the second autotransformer is used to control the converter input voltage, therefore the DC link voltage. It should be pointed out that this was a
Abstract— In this paper analysis of an efficient topology of the three-port full bridge dc-dc converter is presented. This topology is promising with the view points of centralised control, compact design as it is capable of interfacing many numbers of ports with less number of switches, low cost, simple and fast powerflow management with reduced conversion process. In a stand-alone system this topology is used to interface renewable energy sources and the load along with the energy storage device. Thus the proposed topology interfaces three ports: as one source port, one bidirectional storage port and an isolated output port. The key feature of this converter is that it performs buck-boost operation on the input port side to obtain power balance in the system with the centralised controller. The centralised controller was implemented by using proportional Integral (PI) controller. Such that it is used to track maximum power from the Photovoltaic (PV) system and to regulate output voltage by controlling the charging and the discharging characteristics of the battery. Zero voltage switching (ZVS) is also achieved in all the switches by using the energy stored in the leakage inductance of the transformer, output filter inductance and capacitance.
Abstract: The energy transportation networks can be improved by multiplying or creating new lines. This is not always the case for various reasons. The series capacities controlled by SCRs (Silicon Controlled Rectifiers) represent a good alternative to optimize the existing or the new electric links, because they allow the increase of the dynamic stability, the damping of the power oscillations, while balancing the loads between the parallel circuits. This paper presents a resolution method to the power distribution by inserting the TCSC transit controllerin the network. The insertion of the TCSC devices has given satisfying results that are, an increase of the transmitted active power and reduction of active losses, an improvement of the angular stability and the voltage stability without decreasing the transportation capacity.
PID is the most commonly used control algorithm in the process industry. Also, this technique is used to control the FACTS devices  . However, the nonlinear nature as well as the uncertainties that exist in the system make it difficult to design an effective controller for the FACTS that guarantees fast and stable regulation under all operating conditions. A major source of difficulty is that open-loop plant may change. In particular, inaccuracy in plant may cause problems because the plant is part of the feedback loop. To deal with such a problem, instead of using a single model plant, an uncertain model should be considered. This problem has led to the study of applying adaptive
Therefore in this paper TBMCSL H – bridge Inverter based DSTATCOM control in PS is proposed. A SHPWM technique is used as control for DSTATCOM. The TBMCSL H – bridge Inverter topology based DSTATCOM balances the source currents and reduces THD while improving the load power factor. The simulation of DSTATCOM with its control model is implemented in MatLab/Simulink.
This paper deals with a UnifiedPower Quality Conditioner (UPQC) for load balancing, power factor- correction, voltage regulation, voltage and current harmonics mitigation, mitigation of voltage sag, swell and voltage dip in a three-phase three-wire distribution system for different combinations of linear and non- linear loads.The unifiedpower quality conditioner (UPQC) is a combination of back to back connected shunt and series active power filters (APFs) to a common DC link voltage, which compensates voltage and current based distortions, independently.Using instantaneous active and reactivePower theory ,harmonic detection, reactivepower compensation, voltage sag and swell have been simulated and the results are analyzed. The operation and capability of the proposed system was analyzed through simulations with MATLAB / SIMULINK.
Microphone Preamplifier is to pre amplify the audio signals from the microphone or line (CD player, EVD player, etc...).Tone Preamplifier is to lift and cut the low frequency and high frequency of the signal. Equalizer is to adjust the balance between frequency components within an electronic signal then we need. Line Amplifier is to get the better sound force to the output power amplifier from the audio signals. Output Power Amplifier is to amplify the audio signals and to reach the necessary amount of watts.Sound Level Indicator is to indicate the volume of sounds.
The analysis of the 3D volumes for cal- culation of the 3D power Doppler indices by both the observers was performed as follows: initially, the three planes were explored to localize the region with a ma- jor vascularization within the ROIs, taking the axial plane as a reference. The ROI was the MCA territory closest to the transducer. The Virtual Organ Computer-aided AnaLy- sis (VOCAL) was selected for allowing the manual determination of the area in the fetal brain where the 3D power Doppler vascular indices were analyzed. The mea- surement calipers were positioned on the origin and on the apex of the middle cere- bral artery closest to the transducer. Sub- sequently, the sphere mode was selected to define the contours of the previously cali- brated region of interest. Once the ROI was appropriately included in the brain tissue sphere, the VOCAL Shell Histogram key was selected to automatically calculate all the 3D power Doppler vascular indices (VI,
All the measurements were made with a Perkin-Elmer Inductively Coupled Optical Emission Spectrometer, Optima 3000DV, equipped with a peristaltic pump, a cross- flow nebulizer coupled to a Ryton double pass spray chamber of the Scott type and a central torch tube injector with an internal diameter of 2.0 mm. This instrument has a solid state segmented array charge coupled device (SCD) detector and operates sequentially in both radial and axial torch configurations. In the axial viewing mode, the cool plasma recombination area was striped off with a shear gas interface. The entire system is controlled with PE Winlab software. The conditions of operation of the spectrometer are presented in Table 1.