Fuzzification Condition: 2. The grid 3. Rule base current is sinusoidal. It is at a unity PF power factor. De-fuzzification Due to decrease in total effective load, the current The process of transforming arithmetic variables real injected into the grid increases. DC-link voltage is number into linguistic variables fuzzy number is stable, kept near V ideal voltages. The load is a multiple diode bridge-rectifier with R-L load that contains a regressive load.
This step size utilized by Fig: 6. Source voltage at load unbalanced the solver is 1e-6s. The component is subjected to a variety of dynamic statements conditions, such as PCC voltage fluctuations and swells.
Fig: 7. Load voltage: unbalanced load 2. Fig: 4. Power and Energy Magazine, vol Male pour, A. Pahwa, A. Malekpour, and. Transactions on Smart Grid, vol. PP, no. Yang, P. Enjeti, F. Blaabjerg, and H. Adoption of photovoltaic energy: Grid code modifications are explored.
IEEE Ind. Simulation model of PWM - shunt converter no. An approach. Yao, P. Samadi, V. Wong, and R. Management under high. Penetration of. Transactions on Smart. Grid, vol. Chandra and K. Haddad, Power Quality:. Problems and Mitigation Techniques.
Fig: 9. Wiley, Simulation results of load voltage [8] P. Jaya prakash,. Singh, D. Kothari, A. Chandra, and K. Dynamic voltage restorer with. Battery energy. Singh, A. Haddad, Power circumstances. The system appears to be in a stable Quality: Problems and Mitigation Techniques. Bollen and I. Guo, Signal Processing of Power moving average filter. Hoboken: Johm Wiley, example of a contemporary transmission system that Jaya prakash, B.
One of the VSCs is connected in series with a distribution decibels db. If a device does not state the db rating in its specs it 4. To control the power factor at the input port of the UPQC may be better to move on to a different model or where the source is connected. Note that the power factor at manufacturer. A joule controlled by the shunt converter. Let us assume that the before becoming damaged itself. The higher the joule rating, the greater the protection.
Each of the two VSCs is realized by three H-bridge inverters. In its structure, each III. Unified Power Quality Condi tioner switch represents a power semiconductor device e. All the inverters are supplied fro m a power quality of the source current and the load bus voltage.
The secondary distribution sides of energy to the load in case of the transient disturbances in the shunt-connected transformers VSC-1 are connected in source voltage. The configuration of such a device termed as star with the neutral point being connected to the load neutral. The secondary wind ing of the series -connected transformers below.
This is a versatile device similar to a UPFC. The switching action is obtained using output feedback control. In this figure, the feeder impedances are denoted by the pairs Rs1, Ls1 and Rs2, Ls2. It can be seen that the two feeders supply the loads L-1 and L The load L-1 is assumed to have two separate components—an unbalanced part L and a non-linear part L The currents drawn by these two loads are denoted by il1 and il2, respectively. We further assume that the load L-2 is a sensitive load that requires uninterrupted and regulated voltage.
To balance the source currents by in jecting negative and zero sequence components required by the load 2. The co mpensate for the harmonics in the load current by injecting the required harmon ic currents 3. To control the power factor by injecting the required reactive current at fundamental frequency 4. To regulate the DC bus voltage. The series connected converter has the following control objectives: 1.
To balance the voltages at the load bus by injecting negative and zero sequence voltages to compensate for those present in the source. To isolate the load bus fro m harmon ics present in the source voltages, by injecting the harmonic voltages 3.
To regulate the magnitude of the load bus voltage by Fig. In order to mitigate the simu lated voltage sags in the test system of each mit igation technique, also to mit igate voltage sags in practical application, a sinusoidal PWM-based control scheme is imp lemented, with reference to IUPQC.
The aim of the control scheme is to maintain a constant voltage magnitude at the point where sensitive load is connected, under the system disturbance. The control system only measures the rms voltage at load point, in example, no reactive power measurements is required.
Besides, high switching frequencies can be used to improve the efficiency of the converter, without incurring significant switching losses. The IUPQC control system exerts voltage angle control as With a view to have a self regulated dc bus, the voltage across follows: the capacitor is sensed at regular intervals and controlled by An error signal is obtained by comparing the reference voltage emp loying a suitable closed loop control. The DC link voltage, with the rms voltage measured at the load point.
The PI Vdc is sensed at a regular interval and is co mpared with its controller p rocesses the error signal and generates the required reference counterpart Vdc. A limit is put on the output of controller. This voltage is brought back to the reference voltage. In the PWM ensures that the source supplies active power of the load and generators, the sinusoidal signal, Vcontrol , is phase modulated dc bus of the UPQC. Thus, the DC bus voltage of the UPQC is maintained signal carrier in order to generate the switching signals of the to have a proper current control.
Subtraction of load currents VSC valves. The switching frequency if is set at Hz, technique which are further used to drive shunt inverter. It should be noted that, an assumption of balanced response to the PWM gating signals the shunt inverter supplies network and operating conditions are made. It can be In effect, the shunt bi-directional converter that is connected seen in Fig. It injects variable in the control scheme. The speed of response and reactive current to co mpensate current harmonics of the load.
The gain of the voltage of DC capacitor constant. Swell mitigation: A. As far as the common dc lin k voltage is at the reasonable level, the device works satisfactorily. The angle controller ensures that the real power is drawn fro m Feeder-1 to hold the dc link voltage constant.
Therefore, even for a voltage sag or a fau lt in Feeder-2, VSC-1 passes real power through the dc capacitor onto VSC-2 to regulate the voltage.
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