**4.2. Numerical simulation of some fault types**

The numeric simulator of the three phased circuit corresponding to a MVN is shown in Fig.8. The PSPICE program is used to perform the modelization. Several types of faults are simulated using the model:


The MVN where the faults are modelized has the following characteristics:


The simulator contains three lines, denoted with "a", "b" and "c" , so that to each index of parameter such as resistance or inductance is added a, b or c. The line "c" is considered as the healthy line and is the equivalent of all the 20kV lines without fault (Bucatariu et al., 2009; Drapela, 2009)

The line "a" is provided with the possibility of the simulation of a simple grounding fault, by connecting Vsa. The same line "a" might simulate a fault of the type broken conductor (by opening the switch VSGOL). Even more, by opening the switch VSGOL and closing, in the same time, the switch VSa it is possible to simulate a fault of the type broken conductor and grounded on the consumer's side.

The line "b" can simulate a simple grounding fault by closing the switch VSb.

452 Numerical Simulation – From Theory to Industry


on the low voltage side, - Low voltage consumers (C),

the 20kV network,

simulated using the model: - simple grounding fault, - double grounding fault,


distributed on the MV lines.

2009; Drapela, 2009)


delta connection on the 20kV side,

and star with null on the low voltage side),

**4.2. Numerical simulation of some fault types** 


The MVN where the faults are modelized has the following characteristics:








The numeric simulator of the three phased circuit corresponding to a MVN is shown in Fig.8. The PSPICE program is used to perform the modelization. Several types of faults are


The simulator contains three lines, denoted with "a", "b" and "c" , so that to each index of parameter such as resistance or inductance is added a, b or c. The line "c" is considered as the healthy line and is the equivalent of all the 20kV lines without fault (Bucatariu et al.,

The line "a" is provided with the possibility of the simulation of a simple grounding fault, by connecting Vsa. The same line "a" might simulate a fault of the type broken conductor (by opening the switch VSGOL). Even more, by opening the switch VSGOL and closing, in

inductor, a resistor or might be missing in the case of isolated null,

The model is designed with the possibility of changing the values of parameters.


The fault of the type double grounding is simulated by closing the switch VSa connected to the line "a" and closing the switch VSb connected to the line "b", as well.

If a fault of the type double grounding on the same line is wanted to be simulated, the switch VSb should be moved from line "b" to line "a".

The parameters of the Earth (resistance, inductance) are encompassed in the parameters of the electric line.

**Figure 8.** Three phased circuit simulating a MVN
