3. MODELING OF NON-LINEAR LOADS
Computer simulation is the most convenient way of harmonic analysis provided that the system components are modeled accurately and verified either through measurements or mathematically. This section presents the simulation models for some of the commonly used domestic &industrial loads.
3.1 Fluorescent Lamp
Figure 2: Modeling of Fluorescent Lamp in PSCAD/EMTDC
Figure 3: FFT analysis of Fluorescent Lamp
3.2 CFL Lamp
Figure 4: Modeling of CFL Lamp in PSCAD/EMTDC
Figure 5: FFT analysis of CFL Lamp
3.3 Water Pump
Figure 6: Modeling of Water Pump in PSCAD/EMTDC
Figure 7: FFT analysis of Water Pump
3.4 Lift Motor
Figure 8: Modeling of Lift Motor in PSCAD/EMTDC
Figure 9: FFT analysis of Lift Motor
Figure 10: Modeling of Arc Furnaces in PSCAD/EMTDC
Figure 11: FFT analysis of Arc Furnaces
3. RESULT DISCUSSION
FFT analyses of the harmonic on the supply side of the different non-linear loads are found.
The Fluorescent Lamp current has mostly effected by 60-70% of all odd order harmonics that is shown in Figure. The CFL current has mostly effected by 47.3% of 3rd harmonic, 27.9% of 5th order harmonic 19.55% of 7th order harmonic shown in Figure 5. The Water Pump current has mostly effected by 95.84% of 2nd order harmonic, 59.06% of 3rd order harmonic and 44.11% of 14th order harmonic shown in Figure 7. The Lift Motor current has mostly effected by 20.8% of 5th order harmonic, 8.6% of 7th order harmonic and 7.46% of 11th order harmonic shown in Figure 9. The Arc Furnaces current has mostly effected by17.73% of 13th order harmonic, 16.52% of 15th order harmonic and 13.96% of 6th order harmonic are shown in Figure 11.
TABLE 6.2 lists the % of odd and even order harmonics present in supply current of all individual non-linear loads, obtained after FFT analysis. TABLE 6.1 lists the THDs of voltage and current due to the nonlinear loads obtained from simulation result. The load current is also specified. These THDs are calculated based on the individual load ratings. The THD values and the % of harmonics founded in supply current are crossing the limits as compare to the IEC 61000-3-2 Standard and IEEE 519-1992 Standard .
Table 2: Ratings of Domestic and Industrial Loads Modeled in PSCAD
Sl.No. Domestic Load Ratings
1 CFL lamp 20W
2 Fluorescent Lamp 40 W
3 Water pump 5kW,6A
4 Computer Monitor 100W
5 Battery Charger 12V, 3A
6 Adjustable speed drive 3-phase, 400 V, 10 hP
7 Lift Motor 46.3kW,62hP,9A
8 Arc Furnace 3-phase ,400V,25.4 MW
Table 3: Simulation Results of Load Current and THDs for Non-linear Loads
Sl. No. Equipment Name Simulated Irms(A) THDV(%) THDI(%)
1 Computer Monitors 0.374...