Comparison of generic electrical wind turbine models following WECC and IEC standards
is the first test case with IEC and WECC running in parallel.
- T1: an active power setpoint step (-0.5 pu)
- T2: a reactive power setpoint step (0.3 pu)
- T3: a voltage setpoint step (0.03 pu)
- T4: a solid fault at the \ac{wt} terminal (150 ms)
- T5: a fault at the \ac{wt} terminal (150 ms with x_f = 0.2 pu)
- test001_StepP consists in a step on PRef at the turbine.
- test002_StepQ consists in a step on QRef at the turbine.
- test003_SolidFault consists in a solid fault (R = 0, X= 0.0001 pu) at the turbine terminal from t = 5 to t = 5.1 s
- test004_StepU consists in a step on URef at the turbine.
Please note: List is outdated. Maintained version is in report document.
Working document: Relevances to be updated during the investigations.
Relevance:
- 0 ... irrelevant
- 1 ... relevant
- 2 ... very relevant
| No. | Relevance | Description | Test case |
|---|---|---|---|
| 1 | 1 | IEC: PT1 not frozen during FRT (P scaling with different threshold u_pdip instead) | (mentioned in paper) |
| 2 | 1 | IEC: second PT1 element; WECC: no additional PT1 (T_pWTrefA) | (mentioned in paper) |
| 3 | 1 | IEC: additional positive ramp rate limit dpmax4A in PT1 | (mentioned in paper) |
| 4 | 2 | IEC: uses product of (dynamic) CLS value ipmax and voltage u_WTC for PT1 limit; WECC: uses constants Pmax, Pmin; connected to difference 2 and to pos. ramp limits and lags | T5, T5_noramp (mentioned in paper) |
| 5 | IEC: no negative limit in second PT1; WECC: has lower limit Pmin | ||
| 6 | IEC has p_aero output | ||
| 7 | 1 | IEC has low-voltage P scaling option (M_pUscale=1) to reduce pref by voltage-p.u. during voltage dip | (mentioned in paper) |
| No. | Relevance | Description | Test case |
|---|---|---|---|
| 8 | 1 | IEC: |
(mentined in paper) |
| 9 | WECC: has extra min limit for reactive current during FRT (iql1); IEC uses minimum limit from normal path | ||
| 10 | 0 | IEC has local voltage drop compensation (WECC REEC_A doesn't) [added in WECC version REEC_D] | (mentioned in paper) |
| 11 | IEC: Q control voltage drop compensation current measurement has a ground admittance element. i_gs can be larger than i_WT. (WECC: i_gs=i_WT) | ||
| 12 | IEC: U-PI-Controller Limits seperately on proportional and integral Part; WECC: one common limit on output of PI controller | ||
| 13 | IEC: Q-PI-controller limit on integral part and on PI controller output; WECC: Q-PI-Controller limit only on PI Controller output. | ||
| 14 | Mode 2: IEC: 1st order lag before current calculation (WECC: after current calculation) | ||
| 15 | IEC: tan(phi) as parameter; WECC: phi as input signal | ||
| 16 | 2 | IEC: defines post-fault state (F_FRT=2) only in case of under-voltage events; WECC: for over-voltage events as well | (mentioned in paper) |
| 17 | 2 | IEC: different delta u sign in fast current injection (!) | (mentioned in paper) |
| 18 | 2 | IEC: pre-fault voltage calculated by HPF; WECC: by subtraction of Vref0 | T5_Tuss (mentioned in paper) |
| 19 | 1 | WECC: Iql1, Iqh1 are fast-injected current limits (i_qvhook); IEC: iqh1, iqmin are limits for total injected current (i_qcmd) during FRT. | (mentined in paper) |
| 20 | 0 | IEC uses filtered voltage u_WTCfilt for FRT mode detecion; WECC uses unfiltered u_WTC [changed in WECC version REEC_D] | 003 iqCmdPu, see #29 (mentioned in paper) |
| 21 | WECC: uses CLS value Iqmax, Iqmin in Voltage PI controller; IEC: uses constants | ||
| 22 | 1 | IEC: during FRT, gain of voltage PI-controller can be adapted to K_PuFRT and output limiter removed. | (mentioned in paper) |
| No. | Relevance | Description | Test case |
|---|---|---|---|
| 23 | WECC: Current Limiting System (CLS) acts on P and Q control scheme; IEC: CLS passes limits to generator model. Limits inside P,Q contrl schemes are additional parameters. | ||
| 24 | 0 | WECC: Voltage Dependent Limits have only 4 pairs of u / i [increased in REEC_D] | |
| 25 | 1 | IEC: diffrent parameter i_maxdip during FRT; WECC: same imax during FRT ((5)) | (mentioned in paper) |
| 26 | WECC CSL: makes sure that VDL is always <= imax (this check is not performed in IEC CLS) ((4)) | ||
| 27 | 2 | IEC: high-voltage current limit logic (K_pqu-logic); WECC: no such logic ((3)) | T3_iqlimit (mentioned in paper) |
| 28 | 2 | IEC: P-priority always active outside FRT, regardless of M_qpri; WECC: priority according to setting, also outside FRT ((2)) | T3 (largeStep) (mentioned in paper) |
| 29 | IEC CLS: when subtracting the prioritized quantity, explicitly makes sure that I_cmd doesn't exceed VDL ((1)) | ||
| 30 | 1 | WECC additionally has Thld2, which holds active current limit i_pmax at during-fault-value for Thld2 seconds after fault clearing. | (mentioned in paper) |
| No. | Relevance | Description | Test case |
|---|---|---|---|
| 31 | 1 | IEC: has Q limitation system | (mentioned in paper) |
| No. | Relevance | Description | Test case |
|---|---|---|---|
| 32 | 0 | IEC: measurement in separate model; WECC: measurement inside controller structure | (mentioned in paper) |
| 33 | 2 | WECC: no measurement filter for q | T4 (with tQFilt > 0 in IEC) (mentioned in paper) |
| No. | Relevance | Description | Test case |
|---|---|---|---|
| 34 | 2 | IEC: ip and iq limits applied after the T_g first order lag; WECC: before; see also 27; | T4 (mentioned in paper) |
| 35 | 1 | WECC: iq ramprate limit depends on sign(Qref) | (mentioned in paper) |
| 36 | 0 | WECC: has Low Voltage Power Limit (LVPL) ((comparable to low voltage P reduction in P path?)) [removed in REGC_B] | (mentioned in paper) |
| 37 | WECC: Has high voltage reactive power management and low voltage active power management (for numerical reasons and different in different simulation tools. --> not sensible to include in comparison) | ||
| 38 | 1 | IEC: reference frame rotation block with first order lag model of PLL | (mentioned in paper) |
but added for completeness
| No. | Relevance | Description | Test case |
|---|---|---|---|
| 39 | IEC has included protection module; WECC references external modules from commercial software. --> leave this out of scope |