Distribution Feeder HIF Simulation

ISSN: 2252-8938 IJ-AI Vol. 1, No. 2, June 2012 : 63–72 66

3. SYSTEM MODELING

3.1 Distribution Feeder

A 13.8 kV distribution feeder was performed in PSCAD EMTDC. That consists of a substation and three distribution feeders with radial network. The schematic diagrams are given in Fig 2. The generator is of 30 kV and 10 MV connected to the transformer with 3013.8 kV and 10 MV. The distribution network operates at 13.8 kV voltages. The distribution line is a 20 km long continuously transposed line. The 6-pulse rectifier is used to represent the nonlinear load. The simulation models are developed using PSCAD and the sampling rate chosen is 15.36 kHz. The arcing and nonlinear characteristics of the current signals due to HIFs are similar to other events like load changes and switching operations. Therefore, the simulation of distribution system has been included linear load, non-linear loads and the effect of switching operation, the transient phenomena produced by capacitor switching similar to those of HIFs in frequency domain, so it is necessary to test the reliability of any HIF algorithm under this event. Many of capacitor energisation events have been taken into consideration in the studied distribution system. The conditions for these simulations are summarized in Table 1, where for each case, the current waveform on the feeder is calculated and processed.

3.2 HIF Simulation

In the past, there are several models of HIF have proposed. All of these are based on Emanuel arc model and researchers have tried to complete it and come up to a better model for HIF. A simplified Emanuel model was introduced in 2003. The Two varying resistors were used to represent the fault resistance. A simplified two-diode model of HIF, shown in Figure3 [3]. It was used to generate different HIF currents by changing the parameters resistors and DC source. Resistances ranging from 50 to 1500 ohms were varied and The DC source values were selected from 1 to 10 kV, which led to current value of the simulated HIFs in the range of 8–300 A. Figure. 3 A simplified two-diode model of HIF a Real waveform b Simulated waveform Figure. 4 Comparison of simulated and measured HIF currents IJ-AI ISSN: 2252-8938 Adaptive Neural Subtractive Clustering Fuzzy Inference System for the Detection …. Adnan H. Tawafan 67 Table 1 The Conditions for These Simulations Event Simulation conditions Sending and receiving end capacitor bank operation operation conditions: on and off Load levels: 30, 70 and 100 percent of the full load Source voltage phase angle: 0, 180 Sending Capacitor operation: 2.1 and 4.2 MVar Receiving Capacitor operation: 2.1 MVar Existing sending receiving capacitor: 0 and 2.1 MVar Load operation on the feeder operation conditions: three and single phase Load levels operation: 30-70, 70-100 percent of the full load Source voltage phase angle: 0, 180 Existing sending receiving capacitor: 0, 2.1 and 4.2 MVar Non-linear load operation on the feeder operation conditions: three phase Load levels operation: 30-70, 70-100 percent of the full load Source voltage phase angle: 0, 180 Existing sending receiving capacitor: 0, 2.1 and 4.2 MVar Figure 4a shows that real measured HIF current waveform extracted from [18] and Figure 4b shows the simulated waveform current. The qualitative comparison indicates that there is a relatively good correspondence between the real and simulation waveforms. 4. THE PROPOSED ALGORITHM The proposed algorithm includes three important parts: input data preparation, features generation and fault classification. Input data preparation part is described in simulation section. The rest parts are detailed in the next section. Figure5 showed the Structure of the proposed algorithm . Figure. 5 Structure of the proposed algorithm

4.1 Features Generation