Interview with PAC World guru Stig Holst from Sweden

PAC World:  When and where were you born?
S.H.: I was born on March 25, 1949 in Helsingborg, Sweden. My home was in Hoganas a town 25 km north of Helsingborg.

PAC World:  Where did you go to school?
S.H.: My first ten years in school were in Hoganas. Then I studied three years in Helsingborg and received my Bachelor of Science (Electrical Engineering). After 15 months military service I studied for four years at Chalmers University of Technology in Goteborg (Gothenburg) and received my Master of Science in Electric Power Engineering in1973.

PAC World:  What were your interests while in school? 
S.H:  Mostly the studies. I also played the clarinet but stopped while studying at the university.

PAC World:  Do you remember anything from your childhood that you think contributed to you becoming an engineer?
S.H.:  One of my parents’ friends was an engineer (not electrical) and my impression was that he was well paid and had a good life. Probably more relevant I was interested in technical things and I had two cousins (15-20 years older than me) both were working as electricians.  As 15 years old I had my first summer job as an electrician trainee.

PAC World:  Was there a person that had the most influence on you when you were growing up?
S.H.:  My parents, probably mostly my father

PAC World:  When and why did you decide to continue your education?
S.H.:  After my military service my intention was to find a job as electrical engineer (B.Sc.) and in fact I had an offer to start working for the electricity board in Malmo. However, at the end of my military service I somehow decided to apply for studies at Chalmers and was accepted.

PAC World:  How did you choose the university to go to?
S.H.:  In my opinion there were only two universities in Sweden that could offer a complete program of courses for a M.Sc. in Electric Power Engineering in 1969. The alternatives were Chalmers in Goteborg and KTH, Royal Institute of Technology in Stockholm. The distance to Goteborg was more suitable for my Volkswagen Beetle from 1961.

PAC World:   Did you study electric power systems or protection while in college?
S.H.:  Electric power systems (e.g. simulation and calculation of power systems in normal and abnormal conditions, transmission of electrical power, coordination of insulation, electrical machines) was a major part of the last two years. Protection of power system was also included but it was only a very small part of the course.

PAC World:  What was your first job and how did you get it?
S.H.:  My first job was a position as a protection engineer at the Relay Protection Group at Sydkraft AB, Operations Department. A couple of months before I graduated I send my papers to Sydkraft and to ASEA and applied for a job in the electrical field but not particularly in the protection field. Relatively soon Sydkraft offered me a job in the protection group and I accepted. Soon after that ASEA also offered me a job and a place in the ASEA trainee program but that was too late as I already accepted the offer from Sydkraft.

PAC World:  Is there any event from this time that you would never forget?
S.H:  I worked in a small group of four engineers and our manager, also an engineer with lots of experience in power and protection systems. We had problem with too high fault current levels in the 130 kV system and I got the task to investigate the possibility to use reactors in the neutrals of 400/130 kV auto transformers (750 - 500 MVA) to reduce the fault currents. The transformers were of different designs, so I had to do individually calculations for the transformers (I did the calculations by hand!). The result was that reactors (2 to 6 ohms) should have a good influence on the 130 kV fault current level without any major effect on the 400kV system and that was the result we wanted. When I did the calculations one well respected electrical engineer discussed with me the size of the reactors, but I did not understand his result until I realized that he had considered fully insulated power transformers. He claimed that it was not possible to put the reactors in the neutrals of auto transformers so Sydkraft had to replace also the transformers. Anyhow, reactors were implemented in some of the auto transformers and I think (but I am not sure) that a couple of them are still in use.

PAC World:  How did you become a system protection and control engineer?
S.H.: As the Relay Protection Group also was involved in the design of the protection and control system of Sydkraft I become a system protection and control engineer. I was a member of a joint working group between Vattenfall and Sydkraft. The group worked out common and general principles on how to design protection and control systems. I was also a member in different groups for designing protection system for the Swedish transmission system (400 and 220 kV) for example Busbar protection, Redundant protection system of series compensated lines, Selective clearance of small zero sequence currents. These groups were small with only four or five people and I was a young member together with well experienced protection engineers. I enjoyed the work and participation in these groups. It was very inspiring, and I learned a lot from it.

PAC World:  How did your career at Sydkraft develop to bring you to the position of Executive Manager of Power system analysis and protection?
S.H.: I was becoming executive manager of Communication, Protection and Control at Sydkraft Konsult. Most of the protection test engineering’s belonged to this organization. This unit was merged with the Power system analysis and protection at Sydkraft (the mother company) and people were transferred to Sydkraft. I continued to be one of the two executive managers of Power system analysis and protection, the name of the merged department.

PAC World:  What is the most challenging project that you worked on at Sydkraft?
S.H:  Difficult to say but probably it was when I was project manager for consulting service concerning the protection system of the Luzon Power System in the Philippines. The objective was to improve the reliability of the power system. The project comprised studies and advices on organizational set-up for testing and maintenance of the total fault clearance system. We also worked out policies and routines for maintenance of the fault clearance system. Another part of the project was dealing with disturbance analysis. The total project was relatively comprehensive, and I enjoyed the project.

PAC World:  What was the most satisfying project you worked on?
S.H.:  The consulting service in the Philippines was one of them. Another interesting project was when we had to develop our staff in computers. An Apple II was used in the education. The computer was used to measure and record different kinds of switching transients e.g. from capacitors, transformer etc.
There was a need to control the moment of switching, so the guys developed an equipment for controlled switching. The knowledge and experiences led to a product that we called Switchsync. After an agreement with ASEA we manufactured the equipment and ASEA sold them together with their circuit breakers. This was really a nice spin-off of an education and training project.

PAC World:  You have been part of the transition from electromechanical to solid-state relays and then to microprocessor-based protection IEDs. What was the difference between these two transitions?
S.H.:  The transition from electromechanical to solid-state relays was not so dramatic. The solid-state relays were more or less another version of the electromechanical relays. We could see that some of the first-generation solid-state relays had a relatively short lifetime.

The change to microprocessor-based protection IEDs I see as a much bigger step and improvement. In principle you can have the same IED and by downloading different software we have protection for different applications. It was much easier and more flexible to design different filters or combining different signal with logic and adapt the function for specific applications in the software. I think the numerical microprocessor-based technology has been a very important step for the performance of protection relays.

PAC World:  After 23 years at Sydkraft you joined ABB in 1996. What made you move from a utility to a manufacturer?
S.H.: My first contact with ASEA Relays had already been around 1975 so I knew a lot of the people there. At that time there was much more cooperation between utilities and relay manufactures. 
ASEA Relays already wanted me to join them around 1981 but it was difficult to find a suitable job for my wife. We had also built a new house in the south of Sweden. So, the outcome was that I continued my job at Sydkraft. In the mid-nineties there were big organizational changes of our business and our strong unit within protection and control had to be divided in smaller units which could lead to difficulties in keeping and developing the competence of the staff. (No critical mass!)
As I was being welcomed to ASEA Relays I did not hesitate to join them. It was an interesting step to change from user to manufacturer.

PAC World:  What were your responsibilities at ABB?
S.H.:  I had been working in different departments (Market, Product Management, Application) but most of the job had been related to protection application issues. I have also been involved in completely different tasks like dimensioning of input transformer of IEDs.

PAC World: For many years you have been involved with CIGRE. When and why did you join?
S.H.: The management of Sydkraft was positive to engineers’ participation at the CIGRE sessions. I joined the Paris Session the first time in 1980. I visited as many sessions as possible and I learned a lot by listening to the discussions between the experienced expertise of different subjects. Participating at the CIGRE Sessions has been important for my development.

PAC World:  How important do you think is the role of CIGRE for your development as a professional?
S.H.: I think CIGRE is important for the development of competence in our field. The most important for your development is to join suitable working groups and become an active member.

PAC World:  You are also active in IEC TC 95. When did you get involved and what is the difference between your work at CIGRE and IEC?
S.H.:  I got involved in TC95 in 2008 and I am still active. The work in IEC is focused on specific standards. The range of subjects of CIGRE WGs are much wider. I think the participation in a CIGRE WG can be of great value also for young relatively unexperienced engineers in their development. The work in IEC is of course also very developing but I think that the IEC work often requires more experience already when joining if you shall be able to contribute to the work. IEC is more formal with lots of discussions - for example wordings in the documents.

PAC World:  Today we are part of the transition from hard wired protection and control systems to IEC 61850 communications based fully digital substations. What is your opinion about it, the benefits and challenges?
S.H.: I have no problem with this transition. It is a natural step of development. In 2003 I participated in a joint working group between Vattenfall and ABB regarding a fully digital substation. One pilot substation was built and commissioned in 2005. At that time there were no standardized communication system for digital substations like 61850, so a specific company communication system was used. Therefore, it was difficult to use equipment from other vendors in the system and this kind of system should probably not be accepted by the market. However, I think digital substations based on an international communication standard like IEC 61850 will be accepted and equipment from different vendors will be possible to use in the system.

PAC World:  You have done significant amount of work related to the impact of instrument transformers on protection. Do you think that the time of optical sensors has come?
S.H.: It will come gradually, but I think we still will use conventional CT for a very long time. A conventional CT is a relatively simple and inexpensive component and the performance is well known, good and acceptable for most applications. The number of installed CTs is huge and they will not be exchanged only for the reason of replacement to optical sensors. I think the knowledge about CTs and their performances will be important for long time.

PAC World:  The electric power grid today is very different from the power grid of the twentieth century. What do you think about the impact of inverter based distributed energy resources on protection and control systems?
S.H.: I have not studied this problem but if there is none or very limited inertia in the new power grids many of the conventional protection will have difficulties to operate in a correct way. In these grids probably the control systems of the inverters must be involved and take an active part in the protection of the grid.

PAC World:  What do you believe is the best way to share your knowledge and experience with the new generation of protection engineers?
S.H.: I have tried to contribute during many years. I do not know if it is the best way, but I have been teaching in protection courses for almost 40 years. I have also written some conference papers.

PAC World:  What do you think is most important for a protection engineer’s development?
S.H.: I think it is important that the engineers have the possibility to dig deep into problems, discuss with colleagues, do calculations and simulations and find answers. This will of course take some more time, but it is a very important part of the engineer’s development. I think it is much more efficient to do things than to only read about it and as I said above, try to join international WGs.

PAC World:  What is your opinion about centralized substation protection systems?
S.H.: When I started in the protection business one relay basically contained one function. Then we got integrated IEDs with many different protection functions. Today one protection IED can contain all necessary protection functions for one protected object. In fact, as the development progressed, one IED can or will contain functions for several objects or in the future maybe even a complete substation.
I do not see any problem with this functional integration. Principally I can accept integration of all necessary protection functions for a complete substation, but we must consider and be aware of the back-up issues. The Vattenfall/ABB digital pilot substation had a duplicated protection and control system. Each system consisted of one centralized system with a complete protection and control system for the station. There were no other conventional back-up systems. I think the functional integration will continue and we will see centralized substation protection systems in the future. 

PAC World: Have you received any awards and if Yes, which is the one that is the most important to you?
S.H.: Yes, in 2015 I received the IEC 1906 Award (which “honors the IEC experts around the world in recognizing their exceptional recent achievements and contributions to the IEC committees”) and in 2016 I became Distinguished Member of CIGRE. I am honored by both of the awards and think they have the same value to me.

PAC World:  What do you think we need to do to attract more young people to our industry?
S.H.: When meeting young people take the opportunity to explain how wide and comprehensive the protection field really is. It is about power systems, electrical equipment, power transformers, analog signals, digital technique, computers, protection relays and systems and so on.

PAC World:  What is the advice that you would give when you are in front of an audience of young people?
S.H.: I would like many of them to join the protection world, but I should advise them to choose education and job in fields that they are interested in. Another advice is to respect other people even if you don’t have the same opinion.

PAC World:  Is there any event in your life that you will always remember?
S.H.: I will always remember when I by accident was in Berlin in November 1989 and the wall was opened. I was along the wall between Checkpoint Charlie and Brandenburger Tor. Checkpoint Charlie was opened, and a lot of media were there and waited for the opening also there. It was a really emotional and historical moment that I never will forget.

PAC World:  What do you think is your most important personal achievement?
S.H.: I think I have been respected during my career.

PAC World:  You have traveled to many countries. Do you have a favorite place to visit?
S.H.: There are many interesting places to visit in the world, but Paris has always been a favorite. Also, there are many favorite places around where we live in Helsingborg

PAC World:  You have been together for many years. What is the secret?
S.H.: We met in 1975 and have been together since then except for some years when I moved to Vasteras and ASEA. Kerstin did not find a suitable job in Vasteras, so she stayed in Malmo until 2000. I do not know the secret, but I think it is important to respect and help each other.

PAC World:  You are still working in different roles. Do you ever consider retiring?
S.H.: Yes, sometimes, but I have not yet decided when I shall finalize my remaining job and assignments mainly within IEC TC95.
PAC World:  What is your favorite music?
S.H.: I like most music, but I do not enjoy very hard rock. I can enjoy classic music and old pop music like Chicago, Electric Light Orchestra (ELO), Elton John, Queen and many more. I also like Swedish music like ABBA, Avicii and Laleh.

PAC World: Do you have any favorite food?
S.H.: I like fish better than meat but if I had to choose one specific dish it would be brown beans with fried ham. 

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