VSC DC Line Model: VHVDC_A1

Model added in the June 22, 2026 patch of Simulator 24. Beta versions had been available in the 2 months before this, but users should have the June 22, 2026 patch or later to properly use this model)

September 8, 2026 patch of Simulator 24 included support for allowing Ldc = 0 in the DC circuit equation.

October 15, 2026 patch of Simulator 24 removed Kxfmr1ratio and Kxfmr2ratio as input parameters and now auto calculates those values. Also modified initialization when QmodeFlag=1

Model Equations and/or Block Diagrams

Object Parameters:

MeasBus1	OtherObject:0	Measurement Bus 1. This is the terminal bus of the Measurement Branch 1 at which Qac1, Pac1, Vac1 and Theta1 are measured. Note that the parameter MeasFlag1 determines whether the flow is measured into or out of the branch.
MeasBranch1	OtherObject:1	Measurement Branch 1. Branch on which Qac1 and Pac1 are measured. This branch should be in series with the VSCDCLine on the SideBus1 side of the VSCDCLine, but does not have to be directly connected to the terminal SideBus1. If MeasBranch1 is not specified, then the Qac1 and Pac1 will be the output of the converter on Side 1 into the AC system, and Vac1 and Theta1 will be at the Side1Bus converter terminal.
MeasBus2	OtherObject:2	Measurement Bus 2. This is the terminal bus of the Measurement Branch 2 at which Qac2, Pac2, Vac1 and Theta1 are measured. Note that the parameter MeasFlag2 determines whether the flow is measured into or out of the branch.
MeasBranch2	OtherObject:3	Measurement Branch 2. Branch on which Qac2 and Pac2 are measured. This branch should be in series with the VSCDCLine on the SideBus2 side of the VSCDCLine, but does not have to be directly connected to the terminal SideBus2. If MeasBranch2 is not specified, then the Qac2 and Pac2 will be the output of the converter on Side 2 into the AC system, and Vac2 and Theta2 will be at the Side2Bus converter terminal.

Parameters taken from the Power Flow Data input for VSCDCLine objects:

Rdc	Resistance in Ohms of the DC Line used in the DC Line Model
ACMVABase1	For converter at the Side1Bus, Maximum AC MVA which is used as the ACMVABase for the converter dynamic model
Aloss1	For converter at the Side1Bus, Constant term of the converter loss function [kW]
Bloss1	For converter at the Side1Bus, Linear term of the converter loss function [MW per kA] or [kW per Amp]
Pminloss1	For converter at the Side1Bus, Minimum loss of the converter [kW]
ACMVABase2	For converter at the Side2Bus, Maximum AC MVA which is used as the ACMVABase for the converter dynamic model
Aloss2	For converter at the Side2Bus, Constant term of the converter loss function [kW]
Bloss2	For converter at the Side2Bus, Linear term of the converter loss function [MW per kA] or [kW per Amp]
Pminloss2	For converter at the Side2Bus, Minimum loss of the converter [kW]

Integer Parameter Flags:

0	OpMode	0=Interconnection; 1=Islanded operation (for example an off-shore wind farm) (default = 0)
1	Qmode1Flag	Side-1 Q control mode: 0=Q; 1=QV; 2=PF (default = 0)
2	Qmode2Flag	Side-2 Q control mode: 0=Q; 1=QV; 2=PF (default = 0)
3	MeasFlag1	0 indicates that positive flow for MeasBranch1 is leaving MeasBus1 going out to the line. 1 indicates that positive flow for MeasBranch1 is arriving at MeasBus1 coming in from the line.
4	MeasFlag2	0 indicates that positive flow for MeasBranch2 is leaving MeasBu2s going out to the line. 1 indicates that positive flow for MeasBranch2 is arriving at MeasBus2 coming in from the line.

Float Parameters:

Parameter values are not auto-corrected for the VHVDC_A1, but instead internally the model may modify what value is used for the input parameter based on the integration time step. The integration time step in the notes below is denoted as ΔT.

Part of Model		Parameter	Treatment in Numerical Simulation	Description	Default
Network Interface	0	TPLLsync	If <2ΔT use 0 If <4ΔT use 4*ΔT	PLL synchronization time constant for both Side 1 and Side 2 [seconds]	0.05
	1	R1a		Side 1 arm resistance in per unit on Side 1 ACMVABase	0.10
	2	X1a		Side 1 arm resistance in per unit on Side 1 ACMVABase	0.10
DC Line Model	3	Vdcrated		Rated DC voltage of the converters [kV]	525.0
	4	Ldc	If <0 Use 0	DC line total inductance [milli Henry]	129.3
	5	Cdc	If <0 Use 0	DC line total capacitance [micro Farad]	140.5
	6	C1	If <5 Use 5	Equivalence Capacitance of Side 1 converter [micro Farad]	221.7
	7	C2	If <5 Use 5	Equivalence Capacitance of Side 2 converter [micro Farad]	221.7
Main Converter Control on Side 1 for Interconnection Applications	8	Tvac1f2	If <4*ΔT use 0	Side 1, Second AC voltage filter time constant [s]	0.02
	9	TId1f	If <4ΔT use 4ΔT	Side 1, Id filter time constant (>0) [s]	0.02
	10	Tvf1long	If <4*ΔT use 0	Side 1, AC voltage filter long time constant [s]	60.0
	11	Tuq1	If <4ΔT use 4ΔT	Side 1, Integral time of Iq controller (>0) [s]	10.0
	12	DIq1ctrlmax	Use +(absolute value)	Side 1, Maximum Delta Iq control limit [pu]	0.3
	13	Iq1ctrlmax	Use +(absolute value)	Side 1, Maximum Iq control limit [pu]	0.35
	14	Iq1max		Side 1, Maximum Iq limit [pu]	1.1
	15	Kvac1dyn		Side 1, Vac error gain during faults	1.0
	16	dbVac1dyn	Use +(absolute value)	Side 1, Deadband Uac error in faults [pu]	0.1
	17	dVac1th1	Use +(absolute value)	Side 1, First high AC voltage error threshold [pu]	0.1
	18	Tdrop11		Side 1, First delay of high AC voltage error [s]	0.01
	19	dbVdc1		Side 1, Deadband of DC voltage error [pu]	0.01
	20	KVdc1dyn		Side 1, Feedforward Vdc gain	6.0
	21	KpVdc1		Side 1, Gain of Proportional control of DC PI controller	4.0
	22	KiVdc1		Side 1, Gain of Integral control of DC PI controller (>=0. Zero allowed.) [1/s]	0.05
	23	DId1ctrlmax	Use +(absolute value)	Side 1, Maximum Delta Id control limit [pu]	0.3
	24	Id1refrateup	Use +(absolute value)	Side 1, Id limit ramp-up rate [pu/s]. Up is defined as away from zero, therefore this is used in negative ramp direction for Id1min.	9.0
	25	Id1refratedown	Use -(absolute value)	Side 1, Id limit ramp-down rate [pu/s]. Down is defined as towards zero, therefore this is used in positive ramp direction for Id1min.	-9999
Reactive Power Control on Side 1 for Interconnection Applications	26	TVac1	If <4*ΔT use 0	Side 1, Q Control Vac filter time constant [s]	0.02
	27	TP1	If <4*ΔT use 0	Side 1, Q Control P filter time constant [s]	0.5
	28	Tpf1order	If <4*ΔT use 0	Side 1, Smoothing time constant of PF order [s]	1.0
	29	dbVac1	Use +(absolute value)	Side 1, Deadband QV control [pu]	0.0
	30	DVac1max		Side 1, Maximum AC voltage error in Q-V control [pu]	0.2
	31	Kiu1		Side 1, Proportional gain QV control [pu]	20.0
	32	Kdroop1		Side 1, Inverse droop in deltaV/deltaQ [pu]	0.1
	33	dVac1th2	Use +(absolute value)	Side 1, Second high AC voltage error threshold [pu]	0.18
	34	Tdrop12		Side 1, Second delay of high AC voltage error [s]	0.15
	35	pf1min		Side 1, Minimum PF value	0.9
	36	pf1max		Side 1, Maximum PF value	1.0
	37	Qac1max		Side 1, Maximum reactive power [pu]	0.33
	38	Qac1min		Side 1, Minimum reactive power [pu]	-0.33
	39	Qac1refrateup	Use +(absolute value)	Side 1, Reactive power setpoint ramp-rate upper limit [pu/s]	9999
	40	Qac1refratedown	Use +(absolute value)	Side 1, Reactive power setpoint ramp-rate lower limit [pu/s]	-9999
Id1max vs Vac1 Lookup Table for Side 1 in Interconnection applications (When X value is less than previous, the remainder of curve is ignored)	41	Ic1max	If <= 0 then ignore limit	Side 1, Maximum Total Current [pu]	1.1
	42	Tvac1f1	If <4*ΔT use 0	Side 1, First AC voltage filter time constant [s]	0.04
	43	Vac1X1		Side 1, X1 for Id1max vs Vac1 lookup table	0.0
	44	Id1maxY1AC		Side 1, Y1 for Id1max vs Vac1 lookup table	0.2
	45	Vac1X2		Side 1, X2 for Id1max vs Vac1 lookup table	0.5
	46	Id1maxY2AC		Side 1, Y2 for Id1max vs Vac1 lookup table	0.2
	47	Vac1X3		Side 1, X3 for Id1max vs Vac1 lookup table	0.85
	48	Id1maxY3AC		Side 1, Y3 for Id1max vs Vac1 lookup table	1.1
	49	Vac1X4		Side 1, X4 for Id1max vs Vac1 lookup table	2.0
	50	Id1maxY4AC		Side 1, Y4 for Id1max vs Vac1 lookup table	1.1
	51	Vac1X5		Side 1, X5 for Id1max vs Vac1 lookup table	2.1
	52	Id1maxY5AC		Side 1, Y5 for Id1max vs Vac1 lookup table	1.1
	53	Vac1X6		Side 1, X6 for Id1max vs Vac1 lookup table	2.2
	54	Id1maxY6AC		Side 1, Y6 for Id1max vs Vac1 lookup table	1.1
Main Converter Control on Side 1 in Islanded Applications	55	TVac1f3	If <4*ΔT use 0	Side 1, Third AC voltage filter time constant [s]	0.0001
	56	KpVac1w		Side 1, Proportional gain voltage controller [pu]	4.0
	57	KiVac1w		Side 1, Integral gain of voltage controller (>= 0. Zero allowed) [1/s]	2.0
	58	Iq1ctrlmaxw		Side 1, Maximum Iq in Vac control [pu]	0.3
	59	KVac1fw		Side 1, Feed-forward gain in Vac control [pu]	3
	60	Iq1maxw		Side 1, Maximum current Iq [pu]	1.1
	61	TIq1fw	If <4*ΔT use 0	Side 1, Time constant of filter iq [s]	0.02
	62	KpIac1w		Side 1, Proportional gain of current controller [pu]	0.25
	63	KiIac1w		Side 1, Integral gain of current controller (> 0. Zero not allowed) [1/s]	2.0
	64	Vc1minw		Side 1, Minimum limit of offshore converter voltage [pu]	-0.1
	65	Vc1maxw		Side 1, Maximum limit of offshore converter voltage [pu]	1.3
DC Chopper	66	Vdc2CHon		DC Chopper, activation threshold voltage [pu]	1.035
	67	KVdc2CH	Use -(absolute value)	DC Chopper, Proportional gain control (<= 0) [pu]	-20.0
	68	TVdc2CH	If <4ΔT use 4ΔT	DC Chopper, Integrator time constant control (>0) [s]	0.025
	69	Idc2CHmax		DC Chopper, Maximum current [pu]	1.4
	70	KIdc2CH	If > 1 use 1	DC Chopper, Proportional gain of current control [pu]	0.9
	71	TIdc2CH	If <4ΔT use 4ΔT	DC Chopper, Integrator time constant of current control [s]	0.15
	72	InomCH		DC Chopper, nominal current [kA]	1.8
	73	ECHmax		DC Chopper, Maximum energy [MJ]	2142.2
Main Converter Control on Side 2	74	Tvac2f2	If <4*ΔT use 0	Side 2, Second AC voltage filter time constant [s]	0.02
	75	TId2f	If <4ΔT use 4ΔT	Side 2, Id filter time constant (>0) [s]	0.02
	76	Tvf2long	If <4*ΔT use 0	Side 2, AC voltage filter long time constant [s]	60.0
	77	Tuq2	If <4ΔT use 4ΔT	Side 2, Integral time of iq controller (>0) [s]	10.0
	78	DIq2ctrlmax	Use +(absolute value)	Side 2, Maximum Delta Iq control limit [pu]	0.3
	79	Iq2ctrlmax	Use +(absolute value)	Side 2, Maximum Iq control limit [pu]	0.35
	80	Iq2max		Side 2, Maximum Iq limit [pu]	1.1
	81	Kvac2dyn		Side 2, Vac error gain during faults	1.0
	82	dbVac2dyn	Use +(absolute value)	Side 2, Deadband Uac error in faults [pu]	0.1
	83	dVac2th1	Use +(absolute value)	Side 2, First high AC voltage error threshold [pu]	0.1
	84	Tdrop21		Side 2, First delay of high AC voltage error [s]	0.01
	85	dbVdc2		Side 2, Deadband of DC voltage error [pu]	0.01
	86	KVdc2dyn		Side 2, Feedforward Vdc gain	6.0
	87	KpVdc2		Side 2, Gain of Proportional control of DC PI controller	4.0
	88	KiVdc2		Side 2, Gain of Integral control of DC PI controller (>=0. Zero allowed.) [1/s]	0.05
	89	DId2ctrlmax	Use +(absolute value)	Side 2, Maximum Delta Id control limit [pu]	0.3
	90	Id2refrateup	Use +(absolute value)	Side 2, Id limit ramp-up rate [pu/s]. Up is defined as away from zero, therefore this is used in negative ramp direction for Id2min.	9.0
	91	Id2refratedown	Use -(absolute value)	Side 2, Id limit ramp-down rate [pu/s]. Down is defined as towards zero, therefore this is used in positive ramp direction for Id2min.	-9999
	92	Tpac2	If <4ΔT use 4ΔT	Side 2, Integral time of active power controller (>0) [s]	20.0
	93	Pac2refrateup	Use +(absolute value)	Side 2, Upper limit of active power setpoint ramp-rate [pu/s]	9999
	94	Pac2refratedown	Use -(absolute value)	Side 2, Lower limit of active power setpoint ramp-rate [pu/s]	-9999
Reactive Power Control on Side 2	95	TVac2	If <4*ΔT use 0	Side 2, QControl Vac filter time constant [s]	0.02
	96	TP2	If <4*ΔT use 0	Side 2, QControl P filter time constant [s]	0.50
	97	Tpf2order	If <4*ΔT use 0	Side 2, Smoothing time constant of PF order [s]	1.00
	98	dbVac2	Use +(absolute value)	Side 2, Deadband QV control [pu]	0.00
	99	DVac2max		Side 2, Maximum AC voltage error in Q-V control [pu]	0.20
	100	Kiu2		Side 2, Proportional gain QV control [pu]	20.0
	101	Kdroop2		Side 2, Inverse droop in deltaV/deltaQ [pu]	0.10
	102	dVac2th2	Use +(absolute value)	Side 2, Second high AC voltage error threshold [pu]	0.18
	103	Tdrop22		Side 2, Second delay of high AC voltage error [s]	0.15
	104	pf2min		Side 2, Minimum PF value	0.90
	105	pf2max		Side 2, Maximum PF value	1.00
	106	Qac2max		Side 2, Maximum reactive power [pu]	0.33
	107	Qac2min		Side 2, Minimum reactive power [pu]	-0.33
	108	Qac2refrateup	Use +(absolute value)	Side 2, Reactive power setpoint ramp-rate upper limit [pu/s]	9999
	109	Qac2refratedown	Use +(absolute value)	Side 2, Reactive power setpoint ramp-rate lower limit [pu/s]	-9999
Id2max vs Vac2 Lookup Table for Side 2 (When X value is less than previous, the remainder of curve is ignored)	110	Ic2max	If <= 0 then ignore limit	Side 2, Maximum Total Current [pu]	1.1
	111	Tvac2f1	If <4*ΔT use 0	Side 2, First AC voltage filter time constant [s]	0.04
	112	Vac2X1		Side 2, X1 for Id1max vs Vac1 lookup table	0.00
	113	Id2maxY1AC		Side 2, Y1 for Id2max vs Vac2 lookup table	0.20
	114	Vac2X2		Side 2, X2 for Id1max vs Vac1 lookup table	0.50
	115	Id2maxY2AC		Side 2, Y2 for Id2max vs Vac2 lookup table	0.20
	116	Vac2X3		Side 2, X3 for Id2max vs Vac2 lookup table	0.85
	117	Id2maxY3AC		Side 2, Y3 for Id2max vs Vac2 lookup table	1.05
	118	Vac2X4		Side 2, X4 for Id2max vs Vac2 lookup table	2.00
	119	Id2maxY4AC		Side 2, Y4 for Id2max vs Vac2 lookup table	1.05
	120	Vac2X5		Side 2, X5 for Id2max vs Vac2 lookup table	2.10
	121	Id2maxY5AC		Side 2, Y5 for Id2max vs Vac2 lookup table	1.05
	122	Vac2X6		Side 2, X6 for Id2max vs Vac2 lookup table	2.20
	123	Id2maxY6AC		Side 2, Y6 for Id2max vs Vac2 lookup table	1.05
Id2min vs Vdc2 Lookup Table for Side 2	124	Vdc2X1min		Side 2, X1 for Id2min vs Vdc2 lookup table	1.05
	125	Id2minY1DC		Side 2, Y1 for Id2min vs Vdc2 lookup table	-1.00
	126	Vdc2X2min		Side 2, X2 for Id2min vs Vdc2 lookup table	1.10
	127	Id2minY2DC		Side 2, Y2 for Id2min vs Vdc2 lookup table	0.00
Id2max vs Vdc2 Lookup Table for Side 2	128	Vdc2X1max		Side 2, X1 for Id2max vs Vdc2 lookup table	0.90
	129	Id2maxY1DC		Side 2, Y1 for Id2max vs Vdc2 lookup table	0.00
	130	Vdc2X2max		Side 2, X2 for Id2max vs Vdc2 lookup table	0.96
	131	Id2maxY2DC		Side 2, Y2 for Id2max vs Vdc2 lookup table	1.10