Demo1-Demo2 models comparison - BEST PATHS project€¦ · 3 June 2017 Evaluation of the performance of Demo #1 converter models against Vendor models in Demo #2 Document info sheet

EVALUATION OF THE

PERFORMANCE OF DEMO 1

CONVERTER MODELS AGAINST

VENDOR MODELS IN DEMO 2

2

June 2017

Evaluation of the performance of Demo #1 converter models

against Vendor models in Demo #2

Disclaimer of warranties and limitation of liabilities

This document has been prepared by BEST PATHS project partners as an account of work carried out within the framework of the EC-GA contract nº 612748.

Neither Project Coordinator, nor any signatory party of BEST PATHS Project Consortium Agreement, nor any person acting on behalf of any of them:

(a) makes any warranty or representation whatsoever, express or implied,

(i) with respect to the use of any information, apparatus, method, process, or similar item disclosed in this document, including merchantability and fitness for a particular purpose, or

(ii) that such use does not infringe on or interfere with privately owned rights, including any party's intellectual property, or

(iii) that this document is suitable to any particular user's circumstance; or

(b) assumes responsibility for any damages or other liability whatsoever (including any consequential damages, even if Project Coordinator or any representative of a signatory party of the BEST PATHS Project Consortium Agreement, has been advised of the possibility of such damages) resulting from your selection or use of this document or any information, apparatus, method, process, or similar item disclosed in this document.

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June 2017



Document info sheet

Document Name: Comparison of simulations results from Demo 1 and Demo 2

Responsible Partner: REE

WP: WP #1

Task: NA

Deliverable nº NA

Version: 0

Version Date: June 13, 2016

Author: REE

Diffusion list

Public

Approvals

Submitted for TC approval

Name Company

Author Alexandra Burgos, Miriam García

REE

Contributors Carmen Longás, Silvia Sanz, Luis Coronado

REE

Document history

Revision Date Main modification Author

1 22/06/17 Fist version REE

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June 2017



Evaluation of the performance of demo 1 converter models against vendor models in demo 2 ............... 1

Executive Summary ............................................................................................................................................... 5

1. Introduction ................................................................................................................................................ 6

Description of work ............................................................................................................................................... 6

2. Comparison results for test #7: Response to an active power set-point change .......................................... 7

Objective ............................................................................................................................................................. 7

Initial conditions ................................................................................................................................................... 7

Test description .................................................................................................................................................... 7

Quantitative comparison test #7 ............................................................................................................................. 8

3. Comparison results for test 17: Dynamic behaviour of the AC voltage control. .......................................... 11

Objective ............................................................................................................................................................ 11

Initial conditions .................................................................................................................................................. 11

Test description ................................................................................................................................................... 11

Quantitative comparison test #17 .......................................................................................................................... 11

4. Comparison results for test 34: Response to a DC voltage setpoint change ............................................... 14

Objective ............................................................................................................................................................ 14

Initial conditions .................................................................................................................................................. 14

Test description ................................................................................................................................................... 14

Quantitative comparison test #34 .......................................................................................................................... 15

5. Conclusions................................................................................................................................................ 17

Annex 1. List of compared signals ....................................................................................................................... 18

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Executive Summary

As part of the R&D activities within Demo #1, simulations have been performed employing an open MMC model elaborated by academic partners. This model is available for public download in the Best Paths website (http://www.bestpaths-project.eu/en/publications). Demo #2 is using three “black box” MMC models provided by HVDC converter manufacturers. In order to know the degree of similarity of the Demo #1 model and the manufacturers’ models, results from a set of simulations have been compared.

Three scenarios were jointly selected by the partners in both Demos among the 39 validation scenarios defined in Demo #2; those scenarios represent changes in active power, reactive power and direct voltage, respectively. The main variables for both converter representations (i.e. active and reactive power, ac and dc voltage and dc current) are compared for the different validation scenarios and the different models provided by manufacturers.

Demo #1 has provided results in a MATLAB format, while Demo #2 has provided results in an EMTP format. In order to protect intellectual property, REE was selected as an independent party in charge of performing the comparison using the ScopeView software. Only simulation results have been employed to carry out the comparison exercise and not the models themselves.

As agreed by the involved partners, the comparison has been quantitative, leading to the conclusion that the simulation results from Demo #1 and Demo #2 are similar for the three selected simulation scenarios, meaning that bias is generally comprised between 1% and 10%.

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1. Introduction

Description of work

As part of the R&D activities within Demo #1, simulations have been performed employing an open MMC model elaborated by academic partners. This model is available for public download in the Best Paths website (http://www.bestpaths-project.eu/en/publications). Demo #2 is using three “black box” MMC models provided by HVDC converter manufacturers. In order to know the degree of similarity of the Demo #1 model and the manufacturers’ models, results from a set of simulations have been compared.

Three scenarios were jointly selected by the partners in both Demos among the 39 validation scenarios defined in Demo #2; those scenarios represent changes in active power, reactive power and direct voltage, respectively. The main variables for both converter representations (i.e. active and reactive power, ac and dc voltage and dc current) are compared for the different validation scenarios and the different models provided by manufacturers.

Demo #1 has provided results in a MATLAB format, while Demo #2 has provided results in an EMTP format. In order to protect intellectual property, REE was selected as an independent party in charge of performing the comparison using the ScopeView software. Only simulation results have been employed to carry out the comparison exercise and not the models themselves.

- Tests used for comparison: test #7, test #17 and test #34 from Demo #2, WP4:

� Test #7: Response to an active power set-point change. � Test #17: Dynamic behaviour of the AC voltage control. � Test #34: Response to a DC voltage set-point change.

Demo #1 has performed the same simulations in order to compare the results.

- Network configuration: the same for the three tests, corresponding to configuration number 1 according to D4.1 Section 5.2.2, strong grid (SCR = 15).

This network model includes: � An HVDC link including the converter stations and converter transformers connected at two

PCC-AC (PCC1 and PCC2) to AC grids with short-circuit impedances (Xcc1 and Xcc2) including zero sequence impedances of the sources.

� The two AC grids represented by ideal voltage sources IN1 and IN2. � Two AC lines in parallel with the HVDC link connecting nodes PCC1 and PCC2. These AC

lines are used to check if the HVDC link is sensitive to various events that may occur on the AC network.

� Loads at PCC1 and PCC2.

Figure 1. Network configuration in test #7

- Variables to be compared (see the complete list of signals in the Annex 1): o Active Power at the PCC. o Reactive Power at the PCC. o AC voltage at the PCC.

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o DC voltage at converter terminals. o DC current at converter terminals.

- Comparison criteria: o Identical: less than 1% bias. o Similar: 1% - 10% bias. o Different: 10% - 20% bias. o Completely different: > 20% bias.

The difference in a variable has been calculated as:

where: o Vdemo1 is the value of the variable in Demo #1. o Vdemo2 is the value of the variable in Demo #2 (as there are three suppliers, there will be

three values for each variable). o Vnominal is the nominal value of the variable:

� Pac nominal: 1000 MW. � Qac nominal: 500 Mvar. � Uac nominal: 400 kV. � Udc nominal: 640 kV. � Idc nominal: 1562 A.

- C1, C2 and C3 will be the comparison between Demo #1 results and Supplier 1, 2 and 3 of Demo

#2 results, respectively. Note that there is no correspondence into the number of supplier in the different tests, e.g. supplier 1 in test #7 could be supplier 1, 2 or 3 in test #17 and test #34

- For all the variables, the time needed for initialization has not been considered in the comparison.

2. Comparison results for test #7: Response to an active power set-point

change

Objective

Compare the operation of the models developed by Demo #1 and Demo #2 under an active power set-point change.

Initial conditions

- Converter 1 (PCC1) with fixed active power control mode (Pac_ramp=1000 MW/s Pac_ref=-1000MW) and AC voltage control mode (Uac_ref= 400 KV, Uac_droop=37.5 Mvar/kV, Qac_ref=0 Mvar, Uac_ramp=80kV/s Qac_ramp=10000 Mvar/s)

- Converter 2 (PCC2) with DC voltage control mode (Vdc_ref= 640kV, Vdc_ramp=128kV/s) and AC voltage control mode (Uac_ref= 400KV, Uac_droop=37.5Mvar/kV, Qac_ref=0 Mvar, Uac_ramp=80kV/s Qac_ramp=10000 Mvar/s)

Test description

- At t= 1s Pac_ref of converter 1 changes from -1000MW to 1000MW. - At t= 6s Pac_ref of converter 1 changes from 1000MW to 0 MW.

100(%)nominal

21 ⋅−=V

VVdiff demodemo

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Quantitative comparison test #7

Table 2 and Figure 1 illustrate the differences in % between Demo #1 and Demo #2 models. The values indicated in the table show the % of samples in which the differences correspond to the headings:

Variable

Comparison

model

supplier

Difference

< 1%

Difference

1-10%

Difference

10-20%

Difference

>20%

Pac PCC1

C1 70% 30% 0% 0%

C2 73% 27% 0% 0%

C3 89% 11% 0% 0%

Qac PCC1

C1 3% 46% 51% 0%

C2 3% 53% 44% 0%

C3 2% 98% 0% 0%

Uac PCC1

C1 100% 0% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Udc PCC1

C1 93% 7% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Idc PCC1

C1 52% 48% 0% 0%

C2 81% 19% 0% 0%

C3 82% 18% 0% 0%

Table 1. Differences in test #7, PCC1

Variable

Comparison

model

supplier

Difference

< 1%

Difference

1-10%

Difference

10-20%

Difference

>20%

Pac PCC2

C1 36% 63% 1% 0%

C2 85% 15% 0% 0%

C3 70% 30% 0% 0%

Qac PCC2

C1 14% 19% 32% 34%

C2 15% 73% 12% 0%

C3 2% 27% 70% 0%

Uac PCC2

C1 100% 0% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Udc PCC2

C1 71% 29% 0% 0%

C2 58% 42% 0% 0%

C3 68% 32% 0% 0%

Idc PCC2

C1 42% 58% 0% 0%

C2 61% 39% 0% 0%

C3 62% 38% 0% 0%


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Figure 1. Comparison for test #7

Regarding the values shown in the table and figures: - The models are “similar”, as differences are lower than 10% in all variables except for Qac. - The differences in Qac result from different control strategies implemented between DEMO 1 and

the vendor models (and among the vendors). In spite of this, the results regarding Uac are “identical” as the converters are connected to strong AC networks.

- In this case, model in Demo #1 is more similar to two of the three models in Demo #2.

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3. Comparison results for test 17: Dynamic behaviour of the AC voltage

control.

Objective

Compare the operation of the AC voltage control mode of the models developed by Demo 1 and Demo 2.

Initial conditions

- Converter 1 with fixed active power control mode (Pac_ramp=1000 MW/s Pac_ref=-1000MW) and AC voltage control mode (Uac_ref= 400KV, Uac_droop=37.5 Mvar/kV, Qac_ref=0Mvar, Uac_ramp=80kV/s Qac_ramp=10000 Mvar/s)

- Converter 2 with DC voltage control mode (Vdc_ref= 640kV, Vdc_ramp=128kV/s) and AC voltage control mode (Uac_ref= 400KV, Uac_droop=37.5Mvar/kV, Qac_ref=0Mvar, Uac_ramp=80kV/s Qac_ramp=10000 Mvar/s)

Test description

- At t=6s Uac_droop of converter 2 changes from 37.5Mvar/kV to 12Mvar/kV. - At t=7s modification of the reactive load at PCC1 in network configuration 1 leading to a negative

voltage step of -8kV. - At t=8s modification of the reactive load at PCC2 in network configuration 1 leading to a negative

voltage step of -8kV. - At t=9s modification of the reactive load at PCC1 leading to a positive voltage step of +8kV. - At t=10s modification of the reactive load at PCC2 leading to a positive voltage step of +8kV. - At t=11s Uac_ref of converter 1 changes from 400kV to 410kV. - At t=12s Uac_ref of converter 2 changes from 400kV to 410kV. - At t=13s Uac_ref of converter 1 changes from 410kV to 400kV. - At t=14s Uac_ref of converter 2 changes from 410kV to 400kV.


Next table and figures include the differences in % between Demo1 and Demo2 models. The values indicated in the table show the % of samples in which the differences correspond to the headings:

Variable

Comparison

model

supplier

Difference

< 1%

Difference

1-10%

Difference

10-20%

Difference

>20%

Pac PCC1

C1 99% 1% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Qac PCC1

C1 4% 95% 1% 0%

C2 3% 90% 5% 3%

C3 4% 93% 3% 0%

Uac PCC1

C1 100% 0% 0% 0%

C2 99% 1% 0% 0%

C3 100% 0% 0% 0%

Udc PCC1

C1 6% 94% 0% 0%

C2 56% 44% 0% 0%

C3 56% 44% 0% 0%

Idc PCC1

C1 25% 75% 0% 0%

C2 80% 20% 0% 0%

C3 67% 33% 0% 0%

Table 3. Differences in #test 17, PCC1

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Variable

Comparison

model

supplier

Difference

< 1%

Difference

1-10%

Difference

10-20%

Difference

>20%

Pac PCC2

C1 36% 64% 0% 0%

C2 97% 3% 0% 0%

C3 89% 11% 0% 0%

Qac PCC2

C1 49% 51% 0% 0%

C2 46% 51% 3% 0%

C3 48% 52% 0% 0%

Uac PCC2

C1 100% 0% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Udc PCC2

C1 100% 0% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Idc PCC2

C1 16% 84% 0% 0%

C2 43% 57% 0% 0%

C3 34% 66% 0% 0%


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Regarding the values shown in the table and figures: - The models are “similar”, as differences are lower than 10% in all variables except for Qac. - Regarding Uac control, models are mostly “identical” as differences in Uac are always below 1%.

It should be noticed that in spite of significant bias in reactive power, this limited bias in AC voltage results from the fact that the AC networks used in those simulations are very strong.

- Again, the differences in Qac result from different control strategies implemented between DEMO 1 and the vendors’ models (and among the vendors).

4. Comparison results for test 34: Response to a DC voltage set point

change

Objective

Compare the operation of the models developed by Demo 1 and Demos 2 under a dc voltage set point change.

Initial conditions

- Converter 1 with P-Vdc droop control (Vdc_ref=640kV, Pac_ref=-500 MW, Vdc_droop=0.032kV/MW) and AC voltage control mode (Uac_ref= 400KV, Uac_droop=37.5Mvar/kV, Qac_ref=0Mvar, Uac_ramp=80kV/s Qac_ramp=10000 Mvar/s)

- Converter 2 with DC voltage control mode (Vdc_ref= 640kV, Vdc_ramp=128kV/s) and AC voltage control mode (Uac_ref= 400KV, Uac_droop=37.5Mvar/kV, Qac_ref=0Mvar, Uac_ramp=80kV/s Qac_ramp=10000 Mvar/s)

Test description

- At t=2s Vdc_ref of converter 2 changes from 640kV to 672kV. - At t=4s Vdc_ref of converter 1 changes from 640kV to 672kV. - At t=6s Vdc_ref of converter 2 changes from 672kV to 640kV. - At t=8s Vdc_ref of converter 1 changes from 672kV to 640kV. - At t=10s Pac_ref of converter 1 changes from -500MW to -400MW. - At t=12s Pac_ref of converter 1 changes from -400MW to -500MW.

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Next table and figures include the differences in % between Demo1 and Demo2 models. The values indicated in the table show the % of samples in which the differences correspond to the headings:

Variable

Comparison

model

supplier

Difference

< 1%

Difference

1-10%

Difference

10-20%

Difference

>20%

Pac PCC1

C1 1% 76% 17% 6%

C2 0% 96% 3% 1%

C3 0% 68% 16% 16%

Qac PCC1

C1 2% 25% 73% 0%

C2 0% 88% 12% 0%

C3 23% 76% 1% 0%

Uac PCC1

C1 100% 0% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Udc PCC1

C1 85% 15% 0% 0%

C2 88% 12% 0% 0%

C3 86% 14% 0% 0%

Idc PCC1

C1 1% 76% 17% 6%

C2 1% 96% 3% 1%

C3 0% 67% 16% 17%


Variable

Comparison

model

supplier

Difference

< 1%

Difference

1-10%

Difference

10-20%

Difference

>20%

Pac PCC2

C1 0% 76% 18% 6%

C2 0% 97% 2% 1%

C3 0% 67% 16% 17%

Qac PCC2

C1 64% 34% 2% 1%

C2 0% 100% 0% 0%

C3 0% 16% 76% 8%

Uac PCC2

C1 100% 0% 0% 0%

C2 100% 0% 0% 0%

C3 100% 0% 0% 0%

Udc PCC2

C1 93% 7% 0% 0%

C2 99% 1% 0% 0%

C3 97% 3% 0% 0%

Idc PCC2

C1 1% 75% 18% 6%

C2 1% 96% 3% 1%

C3 0% 67% 16% 17%


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Regarding the values shown in the table and figures: - The models are “similar” regarding Udc control, as differences in Udc are lower than 10%. - Regarding the other variables, except for Uac (in which models are identical, as the AC networks

considered here are strong), the behaviour could be considered a little different as there is percentage of time that differences are higher than 10%. Nevertheless, most of the times, differences are below 10%.

- Again, the differences in Qac result from different control strategies implemented between DEMO 1 and the vendors’ models (and among the vendors). In spite of this, the models are “identical” for Uac as differences are lower than 1% thanks to the strength of the AC networks.

- In this case, model in Demo #1 is more similar to one of the models in Demo #2.

5. Conclusions

Following the criteria indicated in section 1, the results of the three scenarios used to perform the comparison in Demo #1 are “similar” to the results provided by Demo #2 for those three scenarios, that means that differences are mostly between 1% and 10%. If needed, further comparisons can be made (if deemed relevant), for example on weaker AC networks.

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Annex 1. List of compared signals

Demo 1 Signal Demo 2 Signal Signal description

MC_To_MMC1_Pac_ref_Demo1 MC_To_MMC1/Pac_ref Active power reference (from MC to MC1)

MC_To_MMC2_Pac_ref_Demo1 MC_To_MMC2/Pac_ref Active power reference (from MC to MC2)

MMC1_To_MC_Pac_meas_Demo1 MMC1_To_MC/Pac_meas Active power measurement (from MC1 to

MC)

MMC2_To_MC_Pac_meas_Demo1 MMC2_To_MC/Pac_meas Active power measurement (from MC2 to

MC)

MC_To_MMC1_Qac_ref_Demo1 MC_To_MMC1/Qac_ref

Reactive power reference (from MC to MC1)

MC_To_MMC2_Qac_ref_Demo1 MC_To_MMC2/Qac_ref

Reactive power reference (from MC to MC2)

MMC1_To_MC_Qac_meas_Demo1 MMC1_To_MC/Qac_meas

Reactive power measurement (from MC1 to MC)

MMC2_To_MC_Qac_meas_Demo1 MMC2_To_MC/Qac_meas

Reactive power measurement (from MC2 to MC)

MC_To_MMC1_Uac_ref_Demo1 MC_To_MMC1/Uac_ref AC voltage reference (from MC to MC1) MC_To_MMC2_Uac_ref_Demo1 MC_To_MMC2/Uac_ref AC voltage reference (from MC to MC2)

MMC1_To_MC_Uac_meas_Demo1 MMC1_To_MC/Uac_meas

AC voltage measurement (from MC1 to MC)

MMC2_To_MC_Uac_meas_Demo1 MMC2_To_MC/Uac_meas

AC voltage measurement (from MC2 to MC)

MC_To_MMC1_Uac_droop_Demo1 MC_To_MMC1/Uac_droop AC voltage ramp (from MC to MC1) MC_To_MMC2_Uac_droop_Demo1 MC_To_MMC2/Uac_droop AC voltage ramp (from MC to MC2)

MC_To_MMC1_Udc_ref_Demo1 MC_To_MMC1/Vdc_ref DC voltage reference (from MC to MC1) MC_To_MMC2_Udc_ref_Demo1 MC_To_MMC2/Vdc_ref DC voltage reference (from MC to MC2)

MMC1_To_MC_Udc_meas_Demo1 MMC1_To_MC/Vdc_meas

DC voltage measurement (from MC1 to MC)

MMC2_To_MC_Udc_meas_Demo1 MMC2_To_MC/Vdc_meas

DC voltage measurement (from MC2 to MC)

-MMC1_To_MC_Idc_meas_Demo1 MMC1_To_MC/Idc_n_meas

Negative DC current measurement (from MC1 to MC)

-MMC1_To_MC_Idc_meas_Demo1 MMC1_To_MC/Idc_p_meas

Positive DC current measurement (from MC1 to MC)

-MMC2_To_MC_Idc_meas_Demo1 MMC2_To_MC/Idc_n_meas

Negative DC current measurement (from MC2 to MC)

-MMC2_To_MC_Idc_meas_Demo1 MMC2_To_MC/Idc_p_meas

Positive DC current measurement (from MC2 to MC)

Table 7. Comparison signal list

Documents

Demo1-Demo2 models comparison - BEST PATHS project€¦ · 3 June 2017 Evaluation of the performance of Demo #1 converter models against Vendor models in Demo #2 Document info sheet