The non-linear resistor model consists mainly of a compiled curve that describes, instantaneously, the behaviour of V with respect to I. It is known that the voltage curve with respect to the current in a resistor is a line whose slope is equal to the value of the resistance.

To represent a surge arrester, this line bends as the voltage increases. Hence, a surge arrester dissipates a greater quantity of current if an over voltage or surge occurs, since its resistance decreases.

The resistor can be characterized as follows:

Non-Linear Resistors Characterization

The relation of V must be translated with respect to I (voltage versus current). The user has two options to translate this characteristic. Either the EMTP method, that describes sections in the form of exponential expressions, or using a matrix.

In the first case, the user must provide the information for a number of sections.

For example, the curve drawn in Figure 6 - 7 expresses the I-V relationship in four distinct sections. Three exponential sections (omit section 1 which is linear.) Section 2, delimited by Vmin(0) to Vmin(1) is described with the parameters P(0) and Q(0).

The exponential number i selected will force the user to provide the values of Vmin, P and Q for coefficient 0 to coefficient i-1.

A more simple method consists in describing the curve in a compiled way. For each value of V, the associated current value is entered.

Mask and Parameters

General Tab

Name	Description		Unit
Connection Type	For series elements, Series only; For single-phase shunt elements, only a Y ground connection is allowed; For three-phase shunt elements, Y ground, Y floating or Delta are allowed.
Input Data Format	Select the parameter input type, either using the EMTP method (exponential section) or with a matrix.
	EMTP format
	Number of exponentials	Number of exponential sections of the curve (does not include the first linear section).
	Vref	Base voltage on which the value of Vmin is evaluated.	V
	Vmin	Value of the voltage for each section change. There are as many Vmin values to provide as there are exponential sections.	p.u.
	P	Value characterizing the exponential section. There are as many P values to provide as there are exponential sections.	A
	Q	Value characterizing the exponential section. There are as many Q values to provide as there are exponential sections.	A

Table Tab

Name	Description		Unit
Connection Type	For series elements, Series only; For single-phase shunt elements, only a Y ground connection is allowed; For three-phase shunt elements, Y ground, Y floating or Delta are allowed.
Input Data Format	Select the parameter input type, either using the EMTP method (exponential section) or with a matrix.
	Matrix Format
	Symmetry	The user defines the curve from 0 to +Vmax, and this curve is duplicated for the negative section.
	Asymmetry	The user defines a curve from -Vmax to +Vmax. The negative part can differ from the positive part.	V
	Number of points on the curve	Specifies the number of points characterizing the voltage curve with respect to the current.	p.u.
	V	Vector of voltage points based on the number of points specified by the user. Each point corresponds to a location on the curve.	V
	I	Vector of current points based on the number of points specified by the user. Each point corresponds to a location on the curve.	A

Ports, Inputs, Outputs and Signals Available for Monitoring

List of Available Signals

At acquisition, the following signals are made available by the sensors:

Name	Description
I(a,b,c)_label	Current per phase in the non-linear resistor.
SEG(a,b,c)_label	Exponential section being used.

HYPERSIM Documentation

Shunt Non-Linear Resistor

Description

Mask and Parameters

General Tab

Table Tab

Ports, Inputs, Outputs and Signals Available for Monitoring

List of Available Signals