This PPT About The Double Line To Ground Fault Analysis in electrical power system.in that PPT derive the equation of double line to ground fault step by step.in this PPT show the circuit diagram of double line to ground fault.

1. PREPARED BY:
HARSH SONI
Topic: Double line To Ground Fault Analysis

2. Fig.1 shows a double line-to-ground fault at F in a
power system. The fault may in general have an
impedance as shown.f
Z
Fig.1

3. The current and voltage (to ground) conditions
at the fault are expressed as
The symmetrical components of voltages are
given by
…….(1)
…….(2)
…….(3)

4. From which it follows that
…….(4)
…….(5)
From Eqs. (4) and (5)
or
…….(6)

5. From Eqs. (1),(4) and (6),we can draw the
connection of Sequence networks as shown in
Figs. (2) and (3).
Fig.3
Fig.2

6. ln terms of the Thevenin equivalents, we can
write from Fig. (3)
…….(7)
The above result can be obtained analytically as
follows:
Substituting for , and in terms of Ea in
below Equation and pre multiplying both sides
by
1aV 2aV 0aV
1
Z

7. We get,
…….(8)

8. Pre multiplying both sides by row matrix [1 1
1]and using Eqs.(1) and (2), we get
From Eq. (4), we have
Substituting
…….(9)

9. Substituting this value of in Eq.(9) and
simplifying, we finally get
0aI