Two-Port Models

Two-port models in RAMSES connect two AC (or AC/DC) buses and inject currents at both ends simultaneously. Each model receives the voltage and current phasors at bus 1 ($v_{x1}, v_{y1}, i_{x1}, i_{y1}$) and bus 2 ($v_{x2}, v_{y2}, i_{x2}, i_{y2}$) and computes the algebraic or differential equations governing the device.

The RAMSES data keyword is TWOPOR:

TWOPOR name bus1 bus2 model_name
       param1 param2 ... ;

Usage in Dynamic Data Files

Two-port models are defined with the TWOPOR keyword as standalone records in the dynamic data file. The syntax is:

TWOPOR name bus1 bus2 model_name
       param1 param2 ... ;

Where name is a unique instance name, bus1 and bus2 are the two connection buses, model_name is the two-port model type (e.g., HVDC_LCC, HVDC_VSC), and the remaining parameters are model-specific.

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HVDC Models

twop_HVDC_LCC — Line-Commutated Converter HVDC

Description

Models a point-to-point Line-Commutated Converter (LCC) HVDC link consisting of a rectifier station (bus 1) and an inverter station (bus 2). LCC-HVDC uses thyristor valves that require an external AC voltage for commutation. The rectifier controls DC current (or power), while the inverter controls DC voltage (or extinction angle). Reactive power is always consumed at both stations and must be supplied locally.

The model includes:

• Configurable rectifier control modes: constant current, constant power, minimum firing angle ($\alpha_{\min}$), or blocked
• Configurable inverter control modes: constant voltage, constant extinction angle ($\gamma$), minimum $\gamma$, reduced current, or blocked
• Transformer tap changers on both sides (handled via dctl_hvdc_lim)
• Reactive power compensation shunts on both sides

Scientific Description

Rectifier DC voltage (bridge equation):

$$V_{dr} = B_r \left( \frac{1.35 \, E_r \, V_1}{n_r} \cos\alpha - (0.9549 X_{cr} + 2 R_{cr}) I_d \right)$$

where $B_r$ is the number of rectifier bridges, $E_r$ is the open-circuit secondary voltage, $n_r$ is the transformer ratio, $V_1$ is the AC voltage magnitude, and $I_d$ is the DC current.

Rectifier overlap angle (commutation equation):

$$\cos(\alpha + \mu_r) = \cos\alpha - \frac{\sqrt{2} \, X_{cr} \, n_r \, I_d}{V_1 \, E_r}$$

Inverter DC voltage:

$$V_{di} = B_i \left( \frac{1.35 \, E_i \, V_2}{n_i} \cos\gamma - (0.9549 X_{ci} + 2 R_{ci}) I_d \right)$$

Inverter overlap angle:

$$\cos(\gamma + \mu_i) = \cos\gamma - \frac{\sqrt{2} \, X_{ci} \, n_i \, I_d}{V_2 \, E_i}$$

DC link voltage balance (series resistance $R_L$):

$$V_{dr} - V_{di} = R_L \, I_d$$

Reactive power consumption at the rectifier:

$$Q_1 = P_1 \cdot \frac{2\mu_r + \sin 2\alpha - \sin 2(\mu_r + \alpha)}{\cos 2\alpha - \cos 2(\mu_r + \alpha)}$$

Active power injections (in per unit):

$$P_1 = -\frac{p \, V_{dr} \, I_d}{S_{\text{base1}}}, \qquad P_2 = \frac{p \, V_{di} \, I_d}{S_{\text{base2}}}$$

where $p$ is the number of poles (monopolar or bipolar).

Rectifier control equation (mode-dependent):

rec_ctl	Control mode	Constraint
1	Constant current	$I_{ord} - I_d = 0$
2	Constant power	$P_{set}/V_{dr} - I_d = 0$
-1	Minimum $\alpha$	$\alpha_{\min} - \alpha = 0$
3	Blocked	$I_d = 0$

Inverter control equation (mode-dependent):

inv_ctl	Control mode	Constraint
1	Constant voltage	$V_{di} + R_{comp} I_d - V_{set} = 0$
2	Constant $\gamma$	$\gamma_0 - \gamma = 0$
-2	Minimum $\gamma$	$\gamma_{\min} - \gamma = 0$
-1	Reduced current	$I_{red} - I_d = 0$
3	Blocked	$\gamma = \pi/2$

The current order $I_{ord}$ is obtained from the desired current $I_{des}$ through a first-order filter with time constant $T_p$.

Parameters Table

Parameter	Description	Unit
p	Number of poles (1 = monopolar, 2 = bipolar)	—
rec_ctl	Rectifier control mode (1=current, 2=power, −1=αmin, 3=blocked)	—
inv_ctl	Inverter control mode (1=voltage, 2=γ, −2=γmin, −1=reduced Id, 3=blocked)	—
Br	Number of bridges in series at rectifier	—
Bi	Number of bridges in series at inverter	—
Er	Rectifier open-circuit secondary voltage (at 1 pu AC)	kV
Ei	Inverter open-circuit secondary voltage (at 1 pu AC)	kV
Rcr	Rectifier commutating resistance per bridge	Ω
Xcr	Rectifier commutating reactance per bridge	Ω
Rci	Inverter commutating resistance per bridge	Ω
Xci	Inverter commutating reactance per bridge	Ω
RL	DC line series resistance	Ω
Rcomp	Compounding resistance for voltage control	Ω
Tp	Time constant for power/current order filter	s
Idset	Initial (and setpoint) DC current	kA
nr	Initial rectifier transformer ratio	pu/pu
ni	Initial inverter transformer ratio	pu/pu

Control Structure

Pset or Idset ──► [Power/Current → Ides] ──► [1st-order filter Tp] ──► Iord
                                                                              │
                                                                         rectifier
                                                                         firing angle α
                                                                              │
                                                              Vdr ────────────┘
                                                               │
                                                              ─── RL ─── Vdi
                                                                          │
                                                               inverter: voltage/γ control

The rectifier minimises $\alpha$ (advances firing) to maintain the current order. The inverter maintains DC voltage via the compounding characteristic $V_{set} = V_{di} + R_{comp} I_d$.

Usage Example

TWOPOR  HVDClink  BUS_RECT  BUS_INV  HVDC_LCC
        2          ! p: bipolar
        1          ! rec_ctl: current control
        1          ! inv_ctl: voltage control
        2          ! Br
        2          ! Bi
        200.0      ! Er (kV)
        200.0      ! Ei (kV)
        0.5        ! Rcr (ohm)
        10.0       ! Xcr (ohm)
        0.5        ! Rci (ohm)
        10.0       ! Xci (ohm)
        5.0        ! RL (ohm)
        20.0       ! Rcomp (ohm)
        0.01       ! Tp (s)
        1.5        ! Idset (kA)
        1.0        ! nr
        1.0        ! ni
        ;

---

twop_HVDC_VSC — Voltage Source Converter HVDC

Description

Models a point-to-point VSC-HVDC link in which bus 1 is the AC-side connection and bus 2 is the DC side (DC voltage appears as $v_{x2}$). The converter uses IGBT-based switches that are self-commutating, enabling independent control of active and reactive power on the AC side and DC voltage on the DC side.

The model implements:

• Phase reactor dynamics ($R, L$)
• Phase-Locked Loop (PLL) for grid synchronisation
• Inner current control loops ($d$- and $q$-axis PI controllers)
• Outer loop for active power (P or $V_{dc}$) and reactive power/AC voltage control
• Low-voltage reactive current injection (grid-code FRT support via piecewise-linear characteristic)
• DC capacitor dynamics

Scientific Description

PLL dynamics (tracks $v_q = 0$):

$$\Delta\omega_{pll} = (\omega_{pll} - \omega_{ref}) \cdot 2\pi f_0$$ $$\dot{\theta}_{pll} = \Delta\omega_{pll}, \qquad \omega_{pll} = K_{pw} \, v_q + K_{iw} \int v_q \, dt$$

Park transformation (bus-1 reference frame):

$$i_d = i_x \cos\theta_{pll} + i_y \sin\theta_{pll}, \quad i_q = -i_x \sin\theta_{pll} + i_y \cos\theta_{pll}$$

Phase reactor dynamics (in $x$-$y$ frame):

$$L \frac{d i_x}{dt} = -R \, i_x + \omega_{ref} L \, i_y + v_{md}\cos\theta_{pll} - v_{mq}\sin\theta_{pll} - v_{x1}$$ $$L \frac{d i_y}{dt} = -R \, i_y - \omega_{ref} L \, i_x + v_{mq}\cos\theta_{pll} + v_{md}\sin\theta_{pll} - v_{y1}$$

Inner current controller ($d$-axis, decoupling):

$$v_{md} = v_d - \omega_{pll} L \, i_q + K_p(i_{d,ref} - i_d) + K_i \int(i_{d,ref} - i_d)\,dt$$ $$v_{mq} = v_q + \omega_{pll} L \, i_d + K_p(i_{q,ref} - i_q) + K_i \int(i_{q,ref} - i_q)\,dt$$

Outer active power / DC voltage loop (combined P-V droop):

$$N_1 = \alpha_1 \left(\frac{P_{ref} - P}{S_{base}}\right) + \beta_1 (V_{dc,ref} - V_{dc})$$

The integrator state $N_{1a}$ feeds through gain $K_{pd}$ to produce $i_{d,ref,unlim}$, which is then limited to $[I_{d,\min}, I_{d,\max}]$.

Outer reactive power / AC voltage loop:

$$N_2 = \alpha_2 \left(\frac{Q_{ref} - Q}{S_{base}}\right) + \beta_2 (V_{ac,ref} - V)$$

The integrator state $N_{2a}$ feeds through gain $K_{pq}$ to produce $i_{q,ref1}$.

Low-voltage reactive injection (piecewise-linear):

$$i_{q,ref2} = \begin{cases} -1 & V < V_{s2} \\ \frac{V - V_{s2}}{V_{s1} - V_{s2}} \cdot (-1) & V_{s2} \le V < V_{s1} \\ 0 & V \ge V_{s1} \end{cases}$$

DC capacitor dynamics (electrostatic inertia $H_{dc}$):

$$2 H_{dc} \frac{d V_{dc}}{dt} = i_{m,dc}$$

AC–DC power balance (lossless converter):

$$i_d \, v_{md} + i_q \, v_{mq} + V_{dc} \, i_{dc} \cdot \frac{P_{nom}}{S_{nom}} = 0$$

Current magnitude limit:

$$I_{d,\max} = \frac{P_{nom}}{S_{nom}}, \quad I_{q,\max} = \sqrt{1 - i_{d,ref}^2}$$

Parameters Table

Parameter	Description	Unit
R	Phase reactor resistance	pu
L	Phase reactor inductance	pu
Hdc	DC capacitor electrostatic inertia	s
Snom	Nominal apparent power	MVA
Pnom	Nominal active power (DC side rating)	MW
Kp	Inner current controller proportional gain	—
Ki	Inner current controller integral gain	—
Kpd	Outer $d$-axis loop proportional gain	—
Kid	Outer $d$-axis loop integral gain	—
Kpq	Outer $q$-axis loop proportional gain	—
Kiq	Outer $q$-axis loop integral gain	—
Kpw	PLL proportional gain	—
Kiw	PLL integral gain	—
alpha1	P–V outer loop: active power coefficient	—
beta1	P–V outer loop: DC voltage coefficient	—
alpha2	Q–$V_{ac}$ outer loop: reactive power coefficient	—
beta2	Q–$V_{ac}$ outer loop: AC voltage coefficient	—
Vs1	AC voltage threshold for reactive support activation	pu
Vs2	AC voltage for full reactive support	pu

Internal (auto-initialised) parameters: Pref, Vdcref, Qref, Vacref, switch.

Control Structure

Pref, Vdcref ─► [P-V droop: α1·ΔP + β1·ΔVdc] ─► [Integr. 1/Kid] ─► idref_unlim
                                                                              │
                                                                         [Limiter Idmin/Idmax]
                                                                              │ idref
                                                     [Inner current PI] ◄────┘
                  vd, ω·L·iq ──────────────────────────────────────────► vmd
                  vq, ω·L·id ──────────────────────────────────────────► vmq

Qref, Vacref ─► [Q-Vac droop: α2·ΔQ + β2·ΔVac] ─► [Integr. 1/Kiq] ─► iqref1_unlim
                                                                              │
FRT boost ────► iqref2 ────────────────────────────────────────────────► iqref = iqref1 + iqref2
                                                                              │
                                                     [Inner current PI] ◄────┘

Usage Example

TWOPOR  VSC1  AC_BUS  DC_BUS  HVDC_VSC
        0.003   ! R (pu)
        0.15    ! L (pu)
        3.5     ! Hdc (s)
        1000.0  ! Snom (MVA)
        900.0   ! Pnom (MW)
        1.0     ! Kp
        50.0    ! Ki
        0.0     ! Kpd
        10.0    ! Kid
        0.0     ! Kpq
        20.0    ! Kiq
        2.0     ! Kpw
        40.0    ! Kiw
        1.0     ! alpha1
        0.0     ! beta1
        1.0     ! alpha2
        0.0     ! beta2
        0.9     ! Vs1
        0.5     ! Vs2
        ;

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twop_HVDC_VSC_SC — VSC-HVDC with Self-Commutation (Grid-Forming)

Description

An enhanced VSC-HVDC model with self-commutation capability and synchronous machine emulation. Unlike the standard twop_HVDC_VSC, this variant includes a frequency droop loop (via Kwi, the virtual synchronous machine inertia gain) in the outer active power control, enabling the converter to participate in primary frequency regulation as if it were a synchronous machine. It is suited for modelling converters operating as grid-forming or frequency-supporting devices.

Key differences from twop_HVDC_VSC:

• Outer active power loop uses frequency droop: $N_1 = (1-\omega_1) K_{wi} + (P_0 + \Delta P - P)(S_{base}/S_{nom})$
• The integrator output is accumulated (not driven to zero), producing a continuous $i_{d,ref}$
• External power correction signal $\Delta P$ allows participation in hub-level coordination

Scientific Description

Outer active power control with frequency droop:

$$N_1 = (1 - \omega_1) K_{wi} + \frac{(P_0 + \Delta P - P) \, S_{base}}{S_{nom}}$$ $$\dot{N}_{1a} = \frac{N_1}{K_{ip}}, \quad i_{d,ref,unlim} = N_{1a} + K_{pp} \, N_1$$

where $K_{wi}$ introduces inertia-like damping: when grid frequency deviates from 1 pu, the converter adjusts its active current reference to oppose the deviation.

Outer reactive power control (droop on Q and AC voltage):

$$N_2 = (Q_0 - Q) \cdot \frac{S_{nom}}{...} + N_{1a}$$

The inner current loop equations, PLL, phase reactor, and DC capacitor dynamics are identical to twop_HVDC_VSC.

Current limits (priority to active current):

$$I_{q,\max} = \sqrt{\max(1 - i_{d,ref}^2, 0)}$$

Parameters Table

Parameter	Description	Unit
R	Phase reactor resistance	pu
L	Phase reactor inductance	pu
Hdc	DC capacitor electrostatic inertia	s
Snom	Nominal apparent power	MVA
Pnom	Nominal active power	MW
Kp	Inner current controller proportional gain	—
Ki	Inner current controller integral gain	—
Kpp	Outer active power loop proportional gain	—
Kip	Outer active power loop integral gain	—
Kwi	Frequency droop / virtual inertia gain	—
Kpq	Outer reactive power loop proportional gain	—
Kiq	Outer reactive power loop integral gain	—
Kpw	PLL proportional gain	—
Kiw	PLL integral gain	—
Vs1	AC voltage threshold for reactive support	pu
Vs2	AC voltage for full reactive support	pu

Internal (auto-initialised): DeltaP, P0, Q0, Vac, switch.

Control Structure

ω1 ─────────────► Kwi·(1-ω1) ─►┐
P0, ΔP ─► ΔP/Snom ──────────────┼─► N1 ─► [Int. 1/Kip] ─► N1a ─► idref_unlim
                                 │               │                      │
                                 └───────────────┘         Kpp·N1 ─────┘
                                                                    [Lim] ─► idref ─► [Inner PI] ─► vmd

Usage Example

TWOPOR  VSC_SC1  AC_BUS  DC_BUS  HVDC_VSC_SC
        0.003   ! R (pu)
        0.15    ! L (pu)
        3.5     ! Hdc (s)
        1000.0  ! Snom (MVA)
        900.0   ! Pnom (MW)
        1.0     ! Kp
        50.0    ! Ki
        2.0     ! Kpp (outer P loop P gain)
        5.0     ! Kip (outer P loop I gain)
        10.0    ! Kwi (frequency droop gain)
        0.0     ! Kpq
        20.0    ! Kiq
        2.0     ! Kpw
        40.0    ! Kiw
        0.9     ! Vs1
        0.5     ! Vs2
        ;

---

twop_DCL_WCL — DC Link with Wind Converter Link (Offshore Wind HVDC)

Description

A comprehensive model of an offshore wind HVDC connection consisting of:

• Converter 1 (offshore, bus 1): Grid-forming VSC station connected to an offshore AC network (wind farm collector bus). It controls AC voltage and frequency at the offshore bus (island operation) and exports active power via the DC link.
• DC cable: A lumped-parameter $\pi$-model with series resistance $R_{dc}$ and shunt capacitances at each end (represented as DC capacitors with inertia constants $H_{dc,1}$ and $H_{dc,2}$).
• Converter 2 (onshore, bus 2): Grid-following VSC station connected to the main AC grid. It controls DC voltage (ensuring power balance) and reactive power/AC voltage support.

The model fully captures:

• PLL dynamics at both converters
• Inner $d$-$q$ current control loops at both converters
• Offshore power/speed droop outer loop
• Onshore DC voltage control with Q/$V_{ac}$ support
• DC cable current dynamics
• Current limiters at both ends

Scientific Description

Converter 1 — Offshore (Grid-forming, active power + frequency droop)

Outer active power loop with speed droop:

$$\text{PB}_1 = (1 - \omega_1) K_{wi,1} + \frac{(P_{0,1} + \Delta P - P_1) \, S_{base}}{S_{nom,1}}$$ $$i_{d,ref,1} = \frac{\int \text{PB}_1 \, dt}{K_{ip,1}} + K_{pp,1} \, \text{PB}_1$$

Outer reactive power loop with QV droop (slope $\beta_V$):

$$\text{QB}_1 = V_1 - V_{0,1} + \beta_V (Q_1 - Q_{0,1}) \frac{S_{base}}{S_{nom,1}}$$ $$i_{q,ref,1} = \frac{\int \text{QB}_1 \, dt}{K_{iq,1}} + K_{pq,1} \, \text{QB}_1$$

Converter 2 — Onshore (Grid-following, DC voltage control)

Outer DC voltage loop:

$$\Delta V = V_{dc,ref} - v_{dc,2}$$ $$i_{d,ref,2} = \frac{\int \Delta V \, dt}{K_{id,2}} + K_{pd,2} \, \Delta V$$

Outer Q/$V_{ac}$ control with combined droop:

$$\text{QB}_2 = \alpha_{2,2}(Q_{ref,2} - Q_2)/S_{base} + \beta_{2,2}(V_{0,2} - V_2)$$ $$i_{q,ref,2} = \frac{\int \text{QB}_2 \, dt}{K_{iq,2}} + K_{pq,2} \, \text{QB}_2$$

Phase reactor dynamics (both converters, in $x$-$y$ frame):

$$-\frac{R_k}{L_k} i_{x,k} + \omega_{ref} i_{y,k} + \frac{1}{L_k}(v_{md,k}\cos\theta_k - v_{mq,k}\sin\theta_k - v_{x,k}) = 0$$ $$-\frac{R_k}{L_k} i_{y,k} - \omega_{ref} i_{x,k} + \frac{1}{L_k}(v_{mq,k}\cos\theta_k + v_{md,k}\sin\theta_k - v_{y,k}) = 0$$

DC link (Ohmic drop + shunt capacitors):

$$v_{dc,1} - R_{dc} \, i_{dc} - v_{dc,2} = 0$$ $$2 H_{dc,1} \frac{d v_{dc,1}}{dt} = i_{dc,1} - i_{m,dc,1} - i_{dc}$$ $$2 H_{dc,2} \frac{d v_{dc,2}}{dt} = i_{dc} - i_{m,dc,2} - G \, v_{dc,2} - i_{dc,2}$$

where $G$ is the shunt conductance computed at initialisation to balance active power at the onshore DC terminal.

AC–DC power balance (both converters, lossless):

$$i_{d,k} v_{md,k} + i_{q,k} v_{mq,k} \pm v_{dc,k} \, i_{dc,k} \frac{P_{nom}}{S_{nom,k}} = 0$$

PLL (both stations):

$$\dot{\theta}_{pll,k} = \Delta\omega_{pll,k} = (\omega_{pll,k} - \omega_{ref}) 2\pi f_0$$ $$\omega_{pll,k} = K_{pw,k} \, v_{q,k} + K_{iw,k} \int v_{q,k} \, dt$$

Current limits (both converters):

$$I_{q,\max,k} = \sqrt{\max(1 - i_{d,k}^2, 0)}, \quad I_{d,\max,k} = \frac{P_{nom}}{S_{nom,k}}$$

Parameters Table

Offshore Converter (1)

Parameter	Description	Unit
R_1	Phase reactor resistance	pu
L_1	Phase reactor inductance	pu
Hdc_1	DC capacitor electrostatic inertia	s
Snom_1	Nominal apparent power	MVA
Kpp_1	Outer active power loop proportional gain	—
Kip_1	Outer active power loop integral gain	—
Kwi_1	Speed/frequency droop gain	—
Kpq_1	Outer reactive power loop proportional gain	—
Kiq_1	Outer reactive power loop integral gain	—
Kpw_1	PLL proportional gain	—
Kiw_1	PLL integral gain	—
betaV_1	QV droop slope ($\Delta V / \Delta Q$)	pu/pu

Onshore Converter (2)

Parameter	Description	Unit
R_2	Phase reactor resistance	pu
L_2	Phase reactor inductance	pu
Hdc_2	DC capacitor electrostatic inertia	s
Snom_2	Nominal apparent power	MVA
Kpd_2	Outer $d$-axis (DC voltage) loop proportional gain	—
Kid_2	Outer $d$-axis (DC voltage) loop integral gain	—
Kpq_2	Outer $q$-axis (Q/Vac) loop proportional gain	—
Kiq_2	Outer $q$-axis (Q/Vac) loop integral gain	—
Kpw_2	PLL proportional gain	—
Kiw_2	PLL integral gain	—
alpha2_2	Q–$V_{ac}$ droop: reactive power coefficient	—
beta2_2	Q–$V_{ac}$ droop: AC voltage coefficient	—

DC Link

Parameter	Description	Unit
Pnom	Nominal active power (DC link rating)	MW
R_dc	DC line series resistance	pu
Vdc0	Initial offshore DC voltage	pu

Control Structure

Wind farm ─► Bus 1 (offshore AC)
                  │
          ┌───────┴────────┐
          │  Converter 1   │  PLL → id/iq transform
          │  Grid-forming  │
          │  P/ω droop     │  idref ← P0+ΔP droop + Kwi·Δω
          │  QV droop      │  iqref ← βV·ΔQ
          └───────┬────────┘
                  │ idc1, vdc1
          ┌───────┴──────────────────────────┐
          │   DC CABLE: Rdc, Hdc1, Hdc2      │
          └───────┬──────────────────────────┘
                  │ idc2, vdc2
          ┌───────┴────────┐
          │  Converter 2   │  PLL → id/iq transform
          │  Grid-following│
          │  Vdc control   │  idref ← Kpd·ΔVdc + Kpd·∫ΔVdc
          │  Q/Vac droop   │  iqref ← α2·ΔQ + β2·ΔVac
          └───────┬────────┘
                  │
          Bus 2 (onshore AC grid)

The offshore converter establishes the AC voltage and frequency for the wind farm. The onshore converter maintains DC voltage. An optional hub coordinator can inject a power correction $\Delta P$ to the offshore converter via the parameter DeltaP.

Usage Example

TWOPOR  WF_HVDC  OFFSHORE_BUS  ONSHORE_BUS  DCL_WCL
        0.003    ! R_1 (pu)
        0.15     ! L_1 (pu)
        3.5      ! Hdc_1 (s)
        900.0    ! Snom_1 (MVA)
        2.0      ! Kpp_1
        5.0      ! Kip_1
        10.0     ! Kwi_1
        0.0      ! Kpq_1
        20.0     ! Kiq_1
        2.0      ! Kpw_1
        40.0     ! Kiw_1
        0.05     ! betaV_1
        0.003    ! R_2 (pu)
        0.15     ! L_2 (pu)
        3.5      ! Hdc_2 (s)
        900.0    ! Snom_2 (MVA)
        0.0      ! Kpd_2
        10.0     ! Kid_2
        0.0      ! Kpq_2
        20.0     ! Kiq_2
        2.0      ! Kpw_2
        40.0     ! Kiw_2
        1.0      ! alpha2_2
        0.0      ! beta2_2
        800.0    ! Pnom (MW)
        0.05     ! R_dc (pu)
        1.0      ! Vdc0 (pu)
        ;