Description

The figure below shows the model implementation of the DC circuit breaker model in HYPERSIM, adapted from [1]. The model is made up of two branches:

the auxiliary branch - containing the Load Commutating Switch (LCS) and Ultra Fast Disconnector (UFD) breakers;
the main branch - main circuit breaker with individual surge arresters forming a cell, and an option to select the number of such desired cells.

The individual surge arresters are rated to meet the full voltage and current breaking capability, and the auxiliary DC breaker for lower voltage and current capability.

Under normal operation, the current will flow only through the auxiliary branch and the current in the main breaker is zero. When a DC fault occurs, the LCS immediately commutates the current to the main DC Breaker and the fast disconnector opens. With the mechanical switch in open position, the main DC breaker breaks the current.

The LCS and main breaker switches are based on IGBT and the model allows the user to select the number of IGBTs in series and parallel. The model allows the user to select the switching times of the LCS, UFD, main breakers, and the number of switching times enabled for each breaker (up to 4).

Note:

All switching times are given relative to the trigger signal
Each T1 to T4 value must be larger than the previous one, i.e.: T1 < T2 < T3 < T4. Otherwise, only the first switching time respecting that condition will be operated

Table of Contents

Mask and Parameters

General

Name	Description	Units	Variable = {Possible Values}
Control type	Internal: uses switching times defined on Timing tab. External (input pins) to use signals from the input pins	-
Number of cells in main breaker	Number of cells in the main breaker. From 1 to 10.	-	{1,10}
Include inductance	Include Inductance when checked	-
Resistor	Parallel resistance	Ohm	{0,1e12}
Inductance	Series inductance	H	{0,1e12}
Number of IGBTs in parallel in the LCS	Number of IGBTs in parallel in the LCS	-
Number of IGBTs in parallel in each cell	Number of IGBTs in parallel in each cell	-
Number of IGBTs in series in the LCS	Number of IGBTs in series in the LCS	-
Number of IGBTs in series in each cell	Number of IGBTs in series in each cell	-

Timing

Name	Description	Units	Variable = {Possible Values}
Breaker initial state	Initial state of the corresponding breaker. Open or closed.	-
T1, T2, T3, T4	Four switching times of the corresponding breaker (closing time if initial state is open, opening time otherwise)	s	{0,1e12}
Number of switching times enabled	Number of switching times enabled from 0 to 4. For instance, 2 means only the two first switching are considered.	-	{0,1,2,3,4}

Surge arrester

Name	Description	Units	Variable = {Possible Values}
Points in Zno characteristic	Number of points in Zn0 characteristic. Note: First point must be 0,0	-	{1,12}
Voltage	All voltage points of the Zn0 characteristic	V	{0,1e12}
Current	All current points of the Zn0 characteristic	A	{0,1e12}

Advanced

Name	Description	Units	Variable = {Possible Values}
Ron resistance for each IGBT	Resistance for each IGBT when closed	Ohm	{0,1e12}
Ron resistance for each IGBT	Resistance for each IGBT when open	MOhm	{0,1e12}
Ron resistance for ultra fast disconnector	Resistance of the UFD when closed	Ohm	{0,1e12}
Roff resistance for ultra fast disconnector	Resistance of the UFD when open	MOhm	{0,1e12}

Ports, Inputs, Outputs and Signals Available for Monitoring

Ports

Name	Description
Net_1	Network connection; the "+" indicates the current measurement direction
Net_2	Network connection

Input

I/O NAME	TYPE (UNIT)	DESCRIPTION
Trig	Input (command signal)	Triggering signal. The switching times of the breakers are defined as relative to this signal. Trigger happens when the input is more than threshold value 0.5
ExtCtrl - LCS	Input (command signal)	Command signal of the LCS. Used only if the control type is set to External (input pins)
ExtCtrl - UFD	Input (command signal)	Command signal of the UFD. Used only if the control type is set to External (input pins)
ExtCtrl - Bsig	Input (command signal)	Command signal of the breakers on main branch. Used only if the control type is set to External (input pins). Bundle of size 10. Unconnected pins will be set to 0, which is an “Open” signal to the breaker.
Imain_scp	Output (A)	Current on the main branch
Iaux_scp	Output (A)	Current on the auxiliary branch

Output

None

Sensors

Name	Description	Unit
Bx (x=1 to 10)	Status of each breaker
Trig	Trigger signal status
UFD	Status of UFD
LCS	Status of LCS
I_aux	Current though auxiliary branch	A
I_main	Current though main branch	A
Bx_int (x=1 to 10)	Internal controlled breaker status
LCS_int	Internal controlled LCS status
UFD_int	Internal controlled UFD status
iSegb_x (x=1 to 10)	Status of breaker cells selected
IZnox (x = 1 to 10)	Current through main branch surge arresters	A

References

J. Häfner, B. Jacobson, "Proactive Hybrid HVDC Breakers - A key innovation for reliable HVDC Grids", International symposium on Electric Power systems of the Future, 13-15 September, 2011

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