master:excac parametersPSCAD Type AC Exciter
Every parameter of the PSCAD Type AC Exciter (master:excac): 176 names, with the unit, the default and the meaning PSCAD gives each one. Copy a name into parameters().
What master:excac is
Type AC Exciter (Type AC exciter), a component of PSCAD's Master Library, filed under machines, exciters and governors.
- Definition
master:excac- PSCAD name
- Type AC Exciter
- Category
- Machines, exciters and governors
- Parameters
- 176, in 18 groups; 162 carry a unit
- Read from
- PSCAD 5.0.0, 2026-11-07
Read and write master:excac in Python
import mhi.pscad
pscad = mhi.pscad.connect() # the PSCAD that is open; launch() starts one
project = pscad.project("my_case") # a case loaded in the workspace
for comp in project.find_all("master:excac"): # the exact definition, namespace first
params = comp.parameters() # every parameter, as PSCAD holds it
print(str(params["EF1_5"])) # Exciter Voltage for SE1 [Efd1], in pu
comp = project.find_all("master:excac")[0]
comp.parameters(EF1_5="11.2 [pu]") # a value that carries a unit is written with it- A parameter is named exactly as in the table, letter case included:
parameters()gives every one of them in a dictionary, and a name the component does not have is refused. - A value that carries a unit comes back as a number whose unit is only in its text, so read it as text first (
str(...)) or the unit is lost. PSCAD keeps a written unit as it is given:"2500 [mohm]"stays in mohm. - A Choice is read and written as its symbol (the capitals in "Written as"), not as the words PSCAD shows in the dialog.
find_all()takes the exact definition only. A wildcard or a bare name withoutmaster:comes back empty; the Builder'spx_findwalks the pages for those.
The Builder's runtime does the same with the unit handled for you: px_get(comp, "EF1_5") and px_set(...), which also records the old value so the case is put back at the end. Getting started shows them.
- Ac5A Exciter Parameters7
- Ac8B Exciter Parameters9
- Ac3A Exciter Parameters14
- Ac8B Regulator Constants10
- Configuration8
- Ac7B Forward Path Parameters14
- Ac1A Forward Path Parameters10
- Ac2A Forward Path Parameters11
- Ac3A Forward Path Parameters10
- Ac4A Regulator Constants10
- Ac5A Regulator Constants4
- Ac6A Forward Path Parameters10
- Ac1A Exciter Parameters12
- Ac2A Exciter Parameters14
- Ac6A Exciter Parameters14
- Ac7B Exciter Parameters14
- Ac5A Feedback Parameters4
- Ac4A Other Signals1
Ac5A Exciter Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
EF1_5Real | pu | 5.60 | Exciter Voltage for SE1 [Efd1]At least 0 |
EF2_5Real | pu | 4.20 | Exciter Voltage for SE2 [Efd2]At least 0 |
EFDMN_5Real | pu | 0.0 | Minimum Exciter Output [EFDMIN]Standard 421.5 specifies that minimum output of the exciter to be zero. However, setting this limit to a large negative value allow the modelling of 1968 IEEE Type 2 excitation system model.At most 0.0 |
KE_5Real | pu | 1.00 | Exciter Constant Related to Field [KE]At least 0 |
SE1_5Real | pu | 0.86 | Saturation at Efd1 [SE(Efd1)]At least 0 |
SE2_5Real | pu | 0.50 | Saturation at Efd2 [SE(Efd2)]At least 0 |
TE_5Real | s | 0.80 | Exciter Time Constant [TE]At least 0 |
Ac8B Exciter Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
EF1_8Real | pu | 4.5 | Exciter Voltage for SE1 [Efd1]At least 0 |
EF2_8Real | pu | 3.38 | Exciter Voltage for SE2 [Efd2]At least 0 |
KC_8Real | pu | 0.55 | Field Circuit Commutating Reactance [KC]At least 0Used when IEEE_Std == 2005 |
KDMG_8Real | pu | 1.1 | Demagnitizing Factor [KD]At least 0Used when IEEE_Std == 2005 |
KE_8Real | pu | 1.0 | Exciter Constant Related to Field [KE]At least 0 |
SE1_8Real | pu | 1.5 | Saturation at Efd1 [SE(Efd1)]At least 0 |
SE2_8Real | pu | 1.36 | Saturation at Efd2 [SE(Efd2)]At least 0 |
TE_8Real | s | 1.0 | Exciter Time Constant [TE]At least 0 |
VFMX_8Real | pu | 6.0 | Field Current Limit [VFEMAX]At least 0Used when IEEE_Std == 2005 |
Ac3A Exciter Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
EFDN_3Real | pu | 2.36 | Efd Value at which KF Changes [EFDN]At least 0 |
KC_3Real | pu | 0.104 | Field Circuit Commutating Reactance [KC]At least 0 |
KD_3Real | pu | 0.499 | Demagnitizing Factor [KD]At least 0 |
KE_3Real | pu | 1.00 | Exciter Constant Related to Field [KE]At least 0 |
KF_3Real | pu | 0.143 | Rate Feedback Gain Below EFDN [KF]At least 0 |
KN_3Real | pu | 0.05 | Rate Feedback Gain Above EFDN [KN]At least 0 |
SE1_3Real | pu | 1.143 | Saturation at VE1 [SE(VE1)]At least 0 |
SE2_3Real | pu | 0.10 | Saturation at VE2 [SE(VE2)]At least 0 |
TE_3Real | s | 1.17 | Exciter Time Constant [TE]At least 0 |
TF_3Real | s | 1.0 | Rate Feedback Time Constant [TF]At least 0 |
VE1_3Real | pu | 6.24 | Exciter Voltage for SE1 [VE1]At least 0 |
VE2_3Real | pu | 4.68 | Exciter Voltage for SE2 [VE2]At least 0 |
VFMX_3Real | pu | 16.0 | Field Current Limit [VFEMAX]At least 0 |
VUEL_3Real | pu | -1.0E10 | Under Excitation Limiter Input [VUEL]Used when (UEL_3!=0) |
Ac8B Regulator Constants
| Parameter | Unit | Default | Description |
|---|---|---|---|
IEEE_StdChoice | · | 1992_ADDENDUM | Select the appropriate IEEE Std 421.5Select the model from 2005 standard or addendum to 1992 standardWritten as 1992_ADDENDUM (1992 addendum), 2005 |
KA_8Real | pu | 1.0 | Regulator Gain [KA]At least 0 |
KD_8Real | pu | 6.0 | PID Derivative Gain [KDR]At least 0 |
KI_8Real | pu | 13.0 | PID Integral Gain [KIR]At least 0 |
KP_8Real | pu | 17.0 | PID Proportional Gain [KPR]At least 0 |
TA_8Real | s | 0.0 | Regulator Time Constant [TA]At least 0 |
TD_8Real | s | 0.03 | PID Derivative Time Constant [TDR]At least 0 |
VLV_8Real | pu | 0.79 | Field Limiter Loop Reference [VLV]At least 0Used when IEEE_Std == 2005 |
VRMN_8Real | pu | 0.0 | Minimum Regulator Output [VRMIN] |
VRMX_8Real | pu | 10.0 | Maximum Regulator Output [VRMAX] |
Configuration
| Parameter | Unit | Default | Description |
|---|---|---|---|
INITInteger | · | 1 | Exciter Status: 0-Initialize;1-NormalEnter a name of a signal that varies from 0 to 1 for initilization |
NameText | · | · | Name for identificationEnter a name for identification |
OVRChoice | · | NO | Output internally computed initial Vref?Enter Yes or NoWritten as NO (No), YES (Yes) |
RCReal | pu | 0.0 | Load Compensating Resistance [Rc]At least 0 |
STABChoice | · | NO | Is there a Stabilizer ?Select Yes or NoWritten as NO (No), YES (Yes) |
TRReal | s | 0.0 | Transducer Time Constant [TR]At least 0 |
TYPEChoice | · | AC2A | AC Exciter TypeSelect the Exciter typeWritten as AC1A, AC2A, AC3A, AC4A, AC5A, AC6A, AC7B, AC8B |
XCReal | pu | 0.0 | Load Compensating Reactance [Xc]At least 0 |
Ac7B Forward Path Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KAI_7Real | pu | 59.69 | Inner PI Integral Gain [KIA]At least 0 |
KAP_7Real | pu | 65.36 | Inner PI Proporational Gain [KPA]At least 0 |
KL_7Real | pu | 10.0 | Lower Limit Multiplying Constant [KL]At least 0 |
KP_7Real | pu | 4.96 | Regulator Multiplying Constant [KP]At least 0 |
KRD_7Real | pu | 0.0 | Regulator Derivative Gain [KDR]At least 0 |
KRI_7Real | pu | 4.24 | Regulator Integral Gain [KIR]At least 0 |
KRP_7Real | pu | 4.24 | Regulator Proporational Gain [KPR]At least 0 |
TRD_7Real | s | 0.0 | Regulator Derivative Time Constant [TDR]At least 0 |
UEL_7Choice | · | NO | Under Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
VAMN_7Real | pu | -0.95 | Minimum Regulator Internal Voltage [VAMIN] |
VAMX_7Real | pu | 1.0 | Maximum Regulator Internal Voltage [VAMAX] |
VLV_7Real | pu | 0.79 | Field Limiter Loop Reference [VLV]At least 0 |
VRMN_7Real | pu | -5.79 | Minimum Regulator Output [VRMIN] |
VRMX_7Real | pu | 5.79 | Maximum Regulator Output [VRMAX] |
Ac1A Forward Path Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KA_1Real | pu | 400.0 | Regulator Gain [KA]At least 0 |
OEL_1Choice | · | NO | Over Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
TA_1Real | s | 0.02 | Regulator Time Constant [TA]At least 0 |
TB_1Real | s | 0.0 | Lag Time Constant [TB]At least 0 |
TC_1Real | s | 0.0 | Lead Time Constant [TC]At least 0 |
UEL_1Choice | · | NO | Under Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
VAMN_1Real | pu | -14.5 | Minimum Regulator Internal Voltage [VAMIN] |
VAMX_1Real | pu | 14.5 | Maximum Regulator Internal Voltage [VAMAX] |
VRMN_1Real | pu | -5.43 | Minimum Regulator Output [VRMIN] |
VRMX_1Real | pu | 6.03 | Maximum Regulator Output [VRMAX] |
Ac2A Forward Path Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KA_2Real | pu | 400.0 | Regulator Gain [KA]At least 0 |
KB_2Real | pu | 25.0 | Second Stage Regulator Gain [KB]At least 0 |
OEL_2Choice | · | NO | Over Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
TA_2Real | s | 0.01 | Regulator Time Constant [TA]At least 0 |
TB_2Real | s | 0.0 | Lag Time Constant [TB]At least 0 |
TC_2Real | s | 0.0 | Lead Time Constant [TC]At least 0 |
UEL_2Choice | · | NO | Under Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
VAMN_2Real | pu | -8.0 | Minimum Regulator Internal Voltage [VAMIN] |
VAMX_2Real | pu | 8.0 | Maximum Regulator Internal Voltage [VAMAX] |
VRMN_2Real | pu | -95. | Minimum Regulator Output [VRMIN] |
VRMX_2Real | pu | 105. | Maximum Regulator Output [VRMAX] |
Ac3A Forward Path Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KA_3Real | pu | 45.62 | Regulator Gain [KA]At least 0 |
KLV_3Real | pu | 0.194 | Field Limiter loop Gain [KLV]At least 0 |
KR_3Real | pu | 3.77 | Regulator and Alternator Field Supply Constant [KR]At least 0 |
TA_3Real | s | 0.013 | Regulator Time Constant [TA]At least 0 |
TB_3Real | s | 0.0 | Lag Time Constant [TB]At least 0 |
TC_3Real | s | 0.0 | Lead Time Constant [TC]At least 0 |
UEL_3Choice | · | NO | Under Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
VAMN_3Real | pu | -0.95 | Minimum Regulator Internal Voltage [VAMIN] |
VAMX_3Real | pu | 1.0 | Maximum Regulator Internal Voltage [VAMAX] |
VLV_3Real | pu | 0.790 | Field Limiter Loop Reference [VLV]At least 0 |
Ac4A Regulator Constants
| Parameter | Unit | Default | Description |
|---|---|---|---|
KA_4Real | pu | 200.0 | Regulator Integral Gain [KA]At least 0 |
KC_4Real | pu | 0.0 | Rectifier Loading Factor [KC]At least 0 |
TA_4Real | s | 0.015 | Regulator Time Constant [TA]At least 0 |
TB_4Real | s | 10.0 | Lag Time Constant [TB]At least 0 |
TC_4Real | s | 1.0 | Lead Time Constant [TC]At least 0 |
UEL_4Choice | · | NO | Under Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
VIMN_4Real | pu | -10.0 | Lower Limit on Error Signal [VIMIN] |
VIMX_4Real | pu | 10.0 | Upper Limit on Error Signal [VIMAX] |
VRMN_4Real | pu | -4.53 | Minimum Regulator Output [VRMIN] |
VRMX_4Real | pu | 5.64 | Maximum Regulator Output [VRMAX] |
Ac5A Regulator Constants
| Parameter | Unit | Default | Description |
|---|---|---|---|
KA_5Real | pu | 400.0 | Regulator Gain [KA]At least 0 |
TA_5Real | s | 0.02 | Regulator Time Constant [TA]At least 0 |
VRMN_5Real | pu | -7.3 | Minimum Regulator Output [VRMIN] |
VRMX_5Real | pu | 7.3 | Maximum Regulator Output [VRMAX] |
Ac6A Forward Path Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KA_6Real | pu | 53.6 | Regulator Gain [KA]At least 0 |
TA_6Real | s | 0.086 | First Lag Time Constant [TA]At least 0 |
TB_6Real | s | 9.0 | Second Lag Time Constant [TB]At least 0 |
TC_6Real | s | 3.0 | Second Lead Time Constant [TC]At least 0 |
TK_6Real | s | 0.18 | First Lead Time Constant [TK]At least 0 |
UEL_6Choice | · | NO | Under Excitation Limit Input Signal?Select Yes or NoWritten as NO (No), YES (Yes) |
VAMN_6Real | pu | -75. | Minimum Regulator Internal Voltage [VAMIN] |
VAMX_6Real | pu | 75. | Maximum Regulator Internal Voltage [VAMAX] |
VRMN_6Real | pu | -36. | Minimum Regulator Output [VRMIN] |
VRMX_6Real | pu | 44. | Maximum Regulator Output [VRMAX] |
Ac1A Exciter Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KC_1Real | pu | 0.20 | Field Circuit Commutating Reactance [KC]At least 0 |
KD_1Real | pu | 0.38 | Demagnitizing Factor [KD]At least 0 |
KE_1Real | pu | 1.00 | Exciter Constant Related to Field [KE]At least 0 |
KF_1Real | pu | 0.03 | Rate Feedback Gain [KF]At least 0 |
SE1_1Real | pu | 0.10 | Saturation at VE1 [SE(VE1)]At least 0 |
SE2_1Real | pu | 0.03 | Saturation at VE2 [SE(VE2)]At least 0 |
TE_1Real | s | 0.80 | Exciter Time Constant [TE]At least 0 |
TF_1Real | s | 1.0 | Rate Feedback Time Constant [TF]At least 0 |
VE1_1Real | pu | 4.18 | Exciter Voltage for SE1 [VE1]At least 0 |
VE2_1Real | pu | 3.14 | Exciter Voltage for SE2 [VE2]At least 0 |
VOEL_1Real | pu | 1.0E10 | Over Excitation Limiter Input [VOEL]Used when (OEL_1!=0) |
VUEL_1Real | pu | -1.0E10 | Under Excitation Limiter Input [VUEL]Used when (UEL_1!=0) |
Ac2A Exciter Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KC_2Real | pu | 0.28 | Field Circuit Commutating Reactance [KC]At least 0 |
KD_2Real | pu | 0.35 | Demagnitizing Factor [KD]At least 0 |
KE_2Real | pu | 1.00 | Excter Constant Related to Field [KE]At least 0 |
KF_2Real | pu | 0.03 | Rate Feedback Gain [KF]At least 0 |
KH_2Real | pu | 1.0 | Field Current Feedback Gain [KH]At least 0 |
SE1_2Real | pu | 0.037 | Saturation at VE1 [SE(VE1)]At least 0 |
SE2_2Real | pu | 0.012 | Saturation at VE2 [SE(VE2)]At least 0 |
TE_2Real | s | 0.60 | Exciter Time Constant [TE]At least 0 |
TF_2Real | s | 1.0 | Rate Feedback Time Constant [TF]At least 0 |
VE1_2Real | pu | 4.4 | Exciter Voltage for SE1 [VE1]At least 0 |
VE2_2Real | pu | 3.3 | Exciter Voltage for SE2 [VE2]At least 0 |
VFMX_2Real | pu | 4.4 | Field Current Limit [VFEMAX]At least 0 |
VOEL_2Real | pu | 1.0E10 | Over Excitation Limiter Input [VOEL]Used when (OEL_2!=0) |
VUEL_2Real | pu | -1.0E10 | Under Excitation Limiter Input [VUEL]Used when (UEL_2!=0) |
Ac6A Exciter Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KC_6Real | pu | 0.173 | Field Circuit Commutating Reactance [KC]At least 0 |
KD_6Real | pu | 1.91 | Demagnitizing Factor [KD]At least 0 |
KE_6Real | pu | 1.6 | Exciter Constant Related to Field [KE]At least 0 |
KH_6Real | pu | 92.0 | Field Current Feedback Gain [KH]At least 0 |
SE1_6Real | pu | 0.214 | Saturation at VE1 [SE(VE1)]At least 0 |
SE2_6Real | pu | 0.044 | Saturation at VE2 [SE(VE2)]At least 0 |
TE_6Real | s | 1.0 | Exciter Time Constant [TE]At least 0 |
TH_6Real | s | 0.08 | Exciter Field Limiter Lag Time [TH]At least 0 |
TJ_6Real | s | 0.02 | Exciter Field Limiter Lead Time [TJ]At least 0 |
VE1_6Real | pu | 7.4 | Exciter Voltage for SE1 [VE1]At least 0 |
VE2_6Real | pu | 5.55 | Exciter Voltage for SE2 [VE2]At least 0 |
VFLM_6Real | pu | 19.0 | Exciter Field Current Reference [VFELIM]At least 0 |
VHMX_6Real | pu | 75.0 | Exciter Field Current Limit [VHMAX ]At least 0 |
VUEL_6Real | pu | 0.00 | Under Excitation Limiter Input [VUEL]Used when (UEL_6!=0) |
Ac7B Exciter Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KC_7Real | pu | 0.18 | Field Circuit Commutating Reactance [KC]At least 0 |
KD_7Real | pu | 0.02 | Demagnitizing Factor [KD]At least 0 |
KE_7Real | pu | 1.0 | Exciter Constant Related to Field [KE]At least 0 |
KF2_7Real | pu | 0.0 | Feedback Gain [KF2]At least 0 |
KF3_7Real | pu | 0.0 | Feedback Derivative Gain [KF3]At least 0 |
KF_7Real | pu | 0.212 | Feedback Gain [KF1]At least 0 |
SE1_7Real | pu | 0.44 | Saturation at VE1 [SE(VE1)]At least 0 |
SE2_7Real | pu | 0.075 | Saturation at VE2 [SE(VE2)]At least 0 |
TE_7Real | s | 1.1 | Exciter Time Constant [TE]At least 0 |
TF3_7Real | s | 0.0 | Feedback Derivative Time Constant [TF3]At least 0 |
VE1_7Real | pu | 6.3 | Exciter Voltage for SE1 [VE1]At least 0 |
VE2_7Real | pu | 3.02 | Exciter Voltage for SE2 [VE2]At least 0 |
VFMX_7Real | pu | 6.9 | Field Current Limit [VFEMAX]At least 0 |
VUEL_7Real | pu | 0.0 | Under Excitation Limiter Input [VUEL]At least -1e+010Used when (UEL_7!=0) |
Ac5A Feedback Parameters
| Parameter | Unit | Default | Description |
|---|---|---|---|
KF_5Real | pu | 0.03 | Rate Feedback Gain [KF]At least 0 |
TF1_5Real | s | 1.0 | Rate Feedback Time Constant [TF1]At least 0 |
TF2_5Real | s | 0.0 | Feedback Lag-Time Constant [TF2]At least 0 |
TF3_5Real | s | 0.0 | Feedback Lead-Time Constant [TF3]At least 0 |
Ac4A Other Signals
| Parameter | Unit | Default | Description |
|---|---|---|---|
VUEL_4Real | pu | -1.0E10 | Under Excitation Limiter Input [VUEL] |
Related
- All 345 definitions in the component reference
- Control tuning: overshoot, rise time and damping
- PSCAD automation with Python: getting started
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