Understanding Differences in Harmonic Restraint and Harmonic ...

More documents

Recommendations

Info

Table 3: Harmonic components in phase B operating currentTable 4: Harmonic components in phase C operating current
We see all phases have sufficient 2 nd harmonic ratio to have the differential operationblocked. However, if a relay is designed with 2 nd harmonic ratio calculated from eachcurrent input instead of the operating current, the 2 nd harmonic ratio is very low inthis event. Tables 5 through 10 give the harmonic components for each phase oftransformer TR2 high side and low side currents separately.Table 5: Harmonic components in TR2 115kV A phase currentTable 6 Harmonic components in TR2 115kV B phase current
Page 4 and 5: Figure 3 Percentage Differential Ch
Page 7 and 8: IopSLP⎞ SLP⎜⎛ 1 100×0.3×2 1
Page 10 and 11: Figure 5: Field recorded waveforms
Page 14 and 15: Table 7 Harmonic components in TR2
Page 16 and 17: Since the secondary relay tripped o
Page 18 and 19: The 1 st slope setting is 25% and t
Page 20: (NSP) at Xcel Energy. He is a regis

Understanding Differences in Harmonic Restraint and Harmonic ...

Create successful ePaper yourself

Delete template?

Save as template?