Dr. V. Sood

johncheng777

原帖由 phdb 于 2007-11-30 15:17 发表

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Thanks johncheng!

Yes, China is now planning to build about 15 UHVDC projects until 2020. You can find these plans  in the internet. And Jiangsu province belonging to State Grid and Guangdong provi ...

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- b/ @! v' _. I( R" W+ R* uThank you for your comments, and Dr.Sood is very interested, I will post his response as below:

9 k8 N4 M7 |! f* S4 s0 n"Cheng
That is helpful definitely.

I can make some comments:

" HVDC is a mature technology now and much has been learnt from the mistakes of the past. However, each link has its own particularities, and there can be some new aspects to learn. Suitable simulation and other studies can help tremendously in doing a good planning.
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) A5 J+ p# U# t1 h* T8 zManufacturers like Siemens and ABB have tremendous experience, and it is necessary to have their input into these projects. Their expertise lies in their capabilities to design and manufacture equipment to stringent specifications.

Too many HVDC links is also a potential problem. There are difficulties in tapping power from HVDC links. They are very good for point to point transmission, but future modifications to adapt to changing needs is not so evident. However, the econonics of planning take this into consideration, and a 30-40 year scenario is often studied; if the link is economical, then why not build it?
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+ l& t* x1 ^/ O( p7 iThe future challenges of tapping HVDC links are being studied, and with developments in force commutated converters will lead the way. The dc breaker technology is advancing also, and will play a role in this. The CCC will assist in commutation, and provide an option for multi-terminal operation. The VSC HVDC will be extremely useful in inter-connections in urban environments, not for long distance transmission. The increasing use of wind power generation will require VSC HVDC technology."

8 r' m7 o+ V: \* UThanks for your help.
- n0 n: g0 W7 e/ W4 OVijay Sood"

phdb

Dr. Sood and Mr. John Cheng,
     Thanks the time of Dr. Sood and Mr. John Cheng took. I am very excited to hear about the opinion of Dr. Sood.
     Thanks Dr. Sood to explain the reason why he wrote in the book of "Applications Of Static Converters In Power Systems" as follows:
     "The first 25 years of HVDC transmission were sustained by converters having mercury arc valves till the mid-1970s. The next 25 years till the year 2000 were sustained by line-commutated converters using thyristor valves. It is predicted that the next 25 years will be dominated by force-commutated converters [4]. Initially, this new force-commutated era has commenced with Capacitor Commutated Converters (CCC) eventually to be replaced by self-commutated converters due to the economic availability of high power switching devices with their superior characteristics." ------------------------------------------------------------in my opinion, I think the LCC, CCC(CSCC) and VSC-HVDC is not the relationship of replacement each other. they are the relationship of complement each other. VSC-HVDC can't instead of LCC-HVDC. I think that's the reason why China now builds so many EHVDC and UHVDC, although we are doing some research of VSC-HVDC.
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0 t; C( f8 I; R: m! |1 z' p     I also have some questions about the comments of Dr. Sood as follows:
     1, Dr Sood wrote that "each link has its own particularities, and there can be some new aspects to learn", Can Dr. Sood give some examples about the new aspects?
6 C5 I7 f' |) F* c# D. m, G     2, "Suitable simulation and other studies can help tremendously in doing a good planning"----I agree with Dr. Sood very much. I want to know why Dr. Sood does not use the electromagnetic transient software fo PSCAD/EMTDC. Also how to define the "Suitalbe simulation", and how to verify the validity and adaptive of HVDC models which you represented. Dr. Sood give some examples about the dynamic analysis of HVDC in the chapter of 10, "TYPICAL DISTURBANCES IN HVDC SYSTEMS", I do not konw how to determine the parameters of KP, KI and some measurement time constant like UD, ID. The step response is just to verify whether they can meet the requirements of system design. Does Dr. Sood have some other solution to determine the parameters? like frequency domain analysis or root locus analysis? And how to use the small signal analysis determining the parameters independently and collectively?
    3, I don't think that the multi-terminal HVDC is a promising technique in China because of the distance of resource and load center. Also the technique is not flexible in system operation and too complicated in system control. What's the opinion of Dr. Sood?
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7 J: g+ B9 k- n0 K, Z& d4 J& B2 Q. ]    I will read the Dr. Sood's book again, I think it is beneficial for me to learn more from that book and this discussion. Thanks Dr. Sood again.

    Now I am focusing on modeling  HVDC syetem detaildly just for ABB tech and SIENMENSE tech. Could Dr. Sood give me some suggestions?
0 h, r+ O) k$ P) V4 |1 \+ Q* |    Also I want to know the opinion of Dr. Sood about the tool of simulation. Now China focuses on modeling the detailed model in electromagnetic transient software PSCAD/EMTDC, and modeling the model on the RTDS. Could Dr. Sood give some suggestions about this? Also I focus on modeling these for BTB-HVDC, EHVDC, UHVDC and EHVAC and analyzing the interaction of AC/DC.
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* k3 K- g3 `; o7 t! S[ 本帖最后由 phdb 于 2007-12-2 11:48 编辑 ]

johncheng777

You are such a hard working guy, and I will forward these comments to Dr. Sood; hopefully, we can receive some feedbacks.

The better comments you post, the more advance technology we can obtain.
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By the way, does anyone else need to say something here?

[ 本帖最后由 johncheng777 于 2007-12-2 11:59 编辑 ]

phdb

The following information is Dr. Sood's interets and research areas, which I copy from his personal website.
  
9 W2 y. I9 B% T   Secretary of IEEE Canada (2006-07), see http://www.ieee.ca/
   Director of the IEEE Canadian Foundation (2002-07), see http://www.ieee.ca/
: \$ V* m7 z) v3 `. Q+ }$ g! ~   Editor of the IEEE Transactions on Power Delivery,
8 z' k6 W- J6 ~) a   Associate Editor of the IFAC journal Control Engineering Practice,
, c9 Z8 I5 R+ S8 `   Associate Editor of IEEE Canadian Journal of Electrical and Computer Engineering
   Associate Editor of IEEE Canadian Review,
: Q* Q+ T: l! sVijay Sood is open to:
# K1 Z* b+ |/ p8 x7 x7 I/ L: `- Consulting work with Industry,
- Preparation and teaching of professional courses,
- Collaborating in areas of his research/expertise, and
7 |' w; f; g8 a; J+ Z& Z) |- Modeling of power systems/power electronics/controllers with EMTP RV
0 c! ~/ W! G/ S( R/ X7 [And when time permits, he plays Bridge, Badminton and likes to travel.
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, p& u& _% N6 r+ J# m6 J& xAreas
Area 1: HVDC and FACTS based power transmission controllers
- |' E' X0 z# V. MArea 2: Monitoring, control & protection of power systems using artificial intelligence techniques
Area 3: Modeling of power electronic converters with EMTP RV (see www.emtp.com)
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I also want to know whether the AI tech will be a promising technique? and will they be widely used in the following HVDC controller development?

johncheng777

Thanks the time of Dr. Sood and Mr. John Cheng took. I am very excited to hear about the opinion of Dr. Sood.
Thanks Dr. Sood to explain the reason why he wrote in the book of "Applications Of Static Converters In Power Systems" as follows:"
  _# ^: K4 e, }) i* j! S& B"The first 25 years of HVDC transmission were sustained by converters having mercury arc valves till the mid-1970s. The next 25 years till the year 2000 were sustained by line-commutated converters using thyristor valves. It is predicted that the next 25 years will be dominated by force-commutated converters [4]. Initially, this new force-commutated era has commenced with Capacitor Commutated Converters (CCC) eventually to be replaced by self-commutated converters due to the economic availability of high power switching devices with their superior characteristics." ------------------------------------------------------------in my opinion, I think the LCC, CCC(CSCC) and VSC-HVDC is not the relationship of replacement each other. they are the relationship of complement each other. VSC-HVDC can't instead of LCC-HVDC. I think that's the reason why China now builds so many EHVDC and UHVDC, although we are doing some research of VSC-HVDC..
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I also have some questions about the comments of Dr. Sood as follows:
1, Dr Sood wrote that "each link has its own particularities, and there can be some new aspects to learn", Can Dr. Sood give some examples about the new aspects?


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5 k$ I, A- A, H& o) FEach new link has its own special problems. Some may be related to resonances, others to operational characteristics depending on the AC network they are feeding into. Specially, China with its many links will be facing problems due to interactions between different ties which are in close proximity to each other. The cheapest version is LCC. If there are commuation problems due to weak AC system, then CCC can be used. If the power capability is low (less than 300 MW) then light HVDC can be used for high quality power. Again, it all depends on the attached AC system.
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. A, A# v  x9 V, P* M! y; B- rChina is going for EHVDC because of bulk power (6000MW), point-to-point transmission only.  Economics is a big reason for this.          
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         2, "Suitable simulation and other studies can help tremendously in doing a good planning"----I agree with Dr. Sood very much. I want to know why Dr. Sood does not use the electromagnetic transient software fo PSCAD/EMTDC. Also how to define the "Suitalbe simulation", and how to verify the validity and adaptive of HVDC models which you represented. Dr. Sood give some examples about the dynamic analysis of HVDC in the chapter of 10, "TYPICAL DISTURBANCES IN HVDC SYSTEMS", I do not konw how to determine the parameters of KP, KI and some measurement time constant like UD, ID. The step response is just to verify whether they can meet the requirements of system design. Does Dr. Sood have some other solution to determine the parameters? like frequency domain analysis or root locus analysis? And how to use the small signal analysis determining the parameters independently and collectively?

I use the EMTP RV program which is similar to EMTDC, or I should state that EMTDC is similar to EMTP. The new version of EMTP RV is vastly enhanced (graphical user interface, machine models, VSC Converter models etc). The tools are all based on the Dommel algorithm. I encourage the reader to visit the website of www.emtp.com <http://www.emtp.com>
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' c( ]$ t+ m: @& J, }( VThe determination of gain parameters is complicated. The theoretical calculations are only approximations based on the data available of the system. The calculations have to be supplemented with simulation studies, and then by actual measurement. There are solutions available to calculate these parameters based on root locus analysis. And I do use them. I supplement these claculations with simulation studies for faster results.


3, I don't think that the multi-terminal HVDC is a promising technique in China because of the distance of resource and load center. Also the technique is not flexible in system operation and too complicated in system control. What's the opinion of Dr. Sood?
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Three terminal operation is feasible, and we have shown that in Quebec (1600 kms, 2000MW). However, it is more complicated control than two terminal transmission. More than 3 terminals is very risky, and not recomended.  Again, HVDC is useful and used only in particular circumstances, not in ALL circumstances. HVDC will complement AC transmission, not supplant it.
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I will read the Dr. Sood's book again, I think it is beneficial for me to learn more from that book and this discussion. Thanks Dr. Sood again.

6 e. n) Q+ u) I8 PNow I am focusing on modeling HVDC syetem detaildly just for ABB tech and SIENMENSE tech. Could Dr. Sood give me some suggestions?!
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; P3 H# u- A7 `" |) D# WThis is very essential; we have been doing this all our life, and still not fully trained. I am learning even now.

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8 ?  R5 w* a, _" P, F) }7 ?Also I want to know the opinion of Dr. Sood about the tool of simulation. Now China focuses on modeling the detailed model in electromagnetic transient software PSCAD/EMTDC, and modeling the model on the RTDS. Could Dr. Sood give some suggestions about this?

Both EMTP and EMTDC are suitable tools. RTDS is good for testing actual (hardware) controllers. I use EMTP RV.

, s5 @8 S: G! o+ l7 uAlso I focus on modeling these for BTB-HVDC, EHVDC, UHVDC and EHVAC and analyzing the interaction of AC/DC."

% u, Y# Z  G; @+ l  G7 U* CI do the same. The models are getting better all the time.

phdb

I am studying the HVDC model embedded in EMTP-RV built by Dr. Sood.

RTDS is good for testing actual (hardware) controllers.
  |8 g1 q' t  J1 `4 B/ f7 \yes, it is good at testing actual controllers. But now China Power Grid Company wants to model the China East Grid or China South Grid on the RTDS, and they add the actual controller to the one which has the most important influence to the system stability. And others they represented by a detailed modeling in the RTDS. So building valid and effective HVDC model on RTDS also is important.
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I use EMTP RV.
/ M  W+ J! k  d$ S0 }& i2 XTheses days I am studing the model which is built by Dr. Sood. I don't think the two DC examples are the detailed one. Could Dr. Sood release a more detailed HVDC model? And what's the advancement of the detailed one? Does it verified by the field test recorder?
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Now, I am always wondering the model which I represented. I do not know how to verify the validity because the field recorder is not easily got from the POWER GRID COMPANY, and the AC system can't be represented precisely as the actual system. Does Dr. Sood have any other methods?
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Perhaps I am not familiar with the EMTP-RV, I feeling that PSCAD/EMTDC is more convenient than EMTP-RV. Some papers have verified that there are no differences for the two tools in simulating HVDC system.
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Also the question I have mentioned in the previous poster is as follows:
"I also want to know whether the AI tech will be a promising technique? and will they be widely used in the following HVDC controller development?"
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) E+ B: T% ~% Z9 y& G[ 本帖最后由 phdb 于 2007-12-5 11:35 编辑 ]

phdb

Dr. Sood said that “RTDS is good for testing actual (hardware) controllers.”
4 E4 A+ T% Q" I$ C        Yes, it is good at testing actual controllers. But now China Power Grid Company wants to model the China East Grid or China South Grid on the RTDS, and they add the actual controller to the one which has the most important influence to the system stability. And others they represented by a detailed modeling in the RTDS. So building valid and effective HVDC model on RTDS also is important.
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# a* b" f/ g1 ~9 N        Before they (China power Grid co.) model it with RTDS, it is better to study with EMTDC or EMTP RV first. This will be easier and less expensive. The files can then be directly transported to RTDS.
       
        Dr. Sood said that “I use EMTP RV.”
3 R; z( }* V7 y: o' [        Theses days I am studying the model which is built by Dr. Sood. I don't think the two DC examples are the detailed one. Could Dr. Sood release a more detailed HVDC model? And what's the advancement of the detailed one? Does it verified by the field test recorder?
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        The two models are simple ones only for beginers to HVDC. A detailed 12 p model is with me but it is not for public release. It is implemented only in EMTP RV, but could easily be built in EMTDC also. The testing with field is not necessary because I have enough experience and know how to state on its validity. The advances includes a gamma controller, voltage controller, applicaton to a weak ac system, advanced VDCL, and frequency modulator.

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        Now, I am always wondering the model which I represented. I do not know how to verify the validity because the field recorder is not easily got from the POWER GRID COMPANY, and the AC system can't be represented precisely as the actual system. Does Dr. Sood have any other methods?

5 g( `. D  Y7 m* {' l, q        It is important to get a good data from the power company.
       
7 I/ G* n  v$ u7 a: h3 f6 h        Perhaps I am not familiar with the EMTP-RV, I feeling that PSCAD/EMTDC is more convenient than EMTP-RV. Some papers have verified that there are no differences for the two tools in simulating HVDC system.
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        EMTP is also validated with field. There is full confidence in this model. The two tools are quite powerful and similar. They use the same Dommel algorithm.
       
9 d$ h0 ?  R0 [        Also the question I have mentioned in the previous poster is as follows:
        "I also want to know whether the AI tech will be a promising technique? and will they be widely used in the following HVDC controller development?"

        This is only a research area. Good results have been obtained but field tests remain to be done. No utility will use this without field testing. My papers on neuro-fuzzy controllers are recommended for further reading. I can send references.

afandi

全是英语   看的费劲啊～～～～～～～～～～～～～～～··

cqtzj

Good questions
thanks...

tanty

I have the same problem!
) N6 E9 W2 k0 r% R; `; fLet us improve our English by practice.