Interview with PACWorld guru Rafael Guerrero

PAC World: When and where were you born?
R.G: I was born on January 20, 1938 in Apan, Hidalgo. Mexico.

PAC World: Where did you go to school?
R.G.: Apan, Apizaco Tlaxcala. Universidad de Puebla and, Universidad Autonoma de Mexico, Mexico City.

PAC World: Do you remember anything from your childhood that you think contributed to you becoming an engineer?
R.G.: No, I don’t think so.

PAC World: Did you play any sports at the time?
R.G.: I was playing different sports. I first started to play baseball. Then I started running 400 m and 800 m and won a local championship. But in university I did not have time for this.
So I started playing basketball and soccer. This ended when I started work at CFE.

PAC World: Why did you decide to continue your education and how did you choose your university?
R.G.: My father used to work in the railroad system, but I didn’t want to work there, so I decided that I should continue my education.
The UNAM (Universidad Autónoma de México) was the most prestigious in Mexico. Its programs included Electrical and Mechanical Engineering.
I learned that mechanical and electrical engineering was the most difficult thing to study. I was looking for a challenge and that is why I selected it.

PAC World: Did you study protection while in college?
R.G: No.

PAC World: Was there any professor that helped you decide your future career path?
R.G: . My best teacher was my thermodynamic teacher, but I cannot say that he had any special influence.

PAC World: How did you start your career?
R.G.: After passing a selection process at CFE (examination on electrical engineering fundamental concepts) I had a chance to start there. However I was rejected by the union. That is why I started first for six months as a test engineer for Industria Electrica de Mexico working on the testing of CTs, VTs, motors, distribution and power transformers.
This gave me a very good understanding of these kinds of equipment. Using impulse generators for testing the equipment also expanded my knowledge about the testing process.
After that I joined CFE as a trainee engineer, participating in the commissioning of plants and substations. We calibrated relays, test breakers, etc.
My first plant that I worked in was the hydroelectric power plant Cupatitzio. All of us knew that in the future we will be relay engineers.
And I was the second one to start in such a role at CFE (8 days later than the first one).

PAC World: What was the next phase in your career?
R.G.: Later they chose the leader of the national office for power system protection responsible for the development of the protection philosophy and principles for Mexico. I still don’t know why they selected me for this position. Maybe it is because I discovered a phase shift of 60 deg at one of the power transformers during the commissioning in another thermal power plant.

PAC World: What triggered your interest in developing power system analysis tools?
R.G: At the time there was a network analyzer donated by GE and based on electronic bulbs. This is when I started working on my short circuit analysis program that I was able to test first at Perdue University in the US.
I also received there a very nice book with algorithms that I can use for my software development. After that I developed also load flow analysis (using Basic), transient stability and other programs using Fortran programing language.
Later I attended some courses at PTI where I got some of the routines (used later in PSS-E) that I can use in my dynamic stability program. After that I extended the reach of my software to load dynamics, as well as the dynamics of power plant equipment.
I am still working on trying to integrate the dynamics of all power system components in a single analysis program, including the dynamic response of instrument transformers.
The availability of the first versions of the EMTP allowed us to fulfil the protection analysis spectrum, that includes the transient response of instrument transformers, ferroresonace of CCVT, etc.

PAC World: What were the challenges you faced in the process of integrating individual power companies into CFE?
R,G: I was commissioned for the relay coordination between CFE and the Chapala electrical systems. The short-circuit calculations was a function of the Analytic Section with people of very bad attitude.
I asked for some short circuit studies but they did not give me any answers. The consequences; my first digital program for short-circuit calculations.

PAC World: You have been involved both in protection engineering and planning. What do you think should be the relationship between the two? Should planning take into consideration protection issues or should protection solve all the system problems?
R.G.: Yes, there is a very strong relationship between them. An example are the low frequency oscillations that can be resolved as a wide area protection solution

PAC World: You have taken courses on many different subjects at different universities or organized by global suppliers. Why do you think this is important for a protection engineer’s development?
R.G.: It is not only very important, it is fundamental for the relay engineer. This could be a personal Rafael opinion.

PAC World: What do you consider the biggest challenge in your professional career?
R.G.: The CAIEEA (Advanced Course on Electrical Engineering for CFE´s Engineers). Sixteen years as Professor on the Master Degree School. It is because I had to develop course materials for everything based on a limited amount of available literature.

PAC World: What do you consider your biggest professional accomplishment?
R.G.: The first single pole fast reclosing with fast extinction of the secondary arc. This was at a time when all engineers from the protection and system analysis departments were moved to the specialized engineering unit.
We decided to attack the single pole tripping and reclosing. There was a 180 km 400 kV line connecting the Mazanillo power plant with the Guadalajara area. Because it was close to the ocean, there were many faults on this line.
We started doing dynamic transient analysis to determine how long we can have the phase open from stability point of view, while at the same time ensuring that the arc will be extinguished. We used an electromechanical transient network analyzer from McGraw-Edison to determine the need for resistors and reactors to ensure the fast secondary arc extinction. It took more than one year to engineer everything and get ready for a staged fault test. We did it when the plant was generating 325 MW.

The first try failed because one of the relays had the pole discrepancy logic enabled. The second try was successful and since then we use single pole trip and reclosing on 400 kV with 400 ms dead interval.
Another thing that I consider an accomplishment is the torsional measurements on the shafts of the Mazatlan Steam Power Plant.
We also came up with a method for converting an existing three phase line to DC which was proven in tests. However this was never realized due to the opposition by some people in the company.
I met the DC transmission guru in ASEA at the time - Erich Uhlmann and he gave me his book that helped me in my analysis.

PAC World: During your career you worked with electromechanical, solid state and microprocessor based protection relays. What do you think about the transition from one technology to another?
R.G.: Nothing more reliable than electromechanical protection relays. The aggregation of series compensation and reclosing modes forced the first transition to solid state relays. I was not very much involved in the transition to microprocessor based relays.
However, we teach all of this in the university - all the filtering, processing, algorithms, etc.
The advance on the communications brought (GPS, synchronizes phasors, etc.) this transition. I had two sessions with Ed Schweitzer at the IEEE Mexico conference about the algorithms in the digital relays that was very valuable to me.

PAC World: In the last ten years we have been in the process of another transition - from the conventional hard wired substation protection and control systems to the IEC 61850 based fully digital substations.
What is your opinion about it, the benefits and challenges?
R.G.: I am not familiar with all the details, but I think that there are three implementation levels. In industrial and distribution systems I can see advantages. The HV transmission systems already has a high degree of intelligence.
But I see significant benefits in the use of this technology for the wide area monitoring and control of low frequency oscillation that I am investigating at this time.
The main challenge is to have equivalent reliability. If this is achieved, I really believe that this is the future of our industry.

PAC World: After many years working for an electric power company you became university professor. What made you do that?
R.G.: I started teaching at the university in 1968. It was a course on electrical power systems. In 1987, or 1988 CFE decided to install a diesel 45 MW generator in a small system. I started fighting this decision which resulted in a lot of tension. This is when PTI invited me to work in Spain. Then I was allowed to retire from CFE.
When I came back from Spain after two years I became a full professor at the university. Believe it or not, this was a knowledge update (wind, photovoltaic, thermo-solar, waste generation, harmonics, inter-harmonics, power electronics, DC transmission, Thermodynamics, heat transfer, and, the traditional subjects, etc) and a personal psychotherapy.

PAC World: What do you think we need to do to attract more young people to our industry?
R.G.: We need to upgrade the programs. Today’s curriculum is not up to date. You may have a teacher that is teaching the same thing for 40 years.
And they don’t want to change. This is not acceptable and it has to be modified.

PAC World: How do you share your knowledge with the people in our industry?
R.G.: I did not have many chances to do that. I have presented some papers at the IEEE conference in Acapulco. I have developed many reports for CFE and was teaching many different courses there as well.
My course materials for the university are also published as well as a couple of books that were published by McGraw Hill.

PAC World: What is the advice that you would give when you are in front of an audience of young people?
R.G.: There is no specific advice. It is to explain to them that everything is in their hands. It is the emphasis on the idea that they are the only group of human beings capable of changing the world.
My experience is that many young people are worried about the situation and we need to help them by discussing all the real issues with them.

PAC World: What do you think about the role of international organizations such as IEEE and CIGRE in the development of our industry?
R.G: In my case, the first plays a fundamental role. I am a member of IEEE and subscribe to the transactions (papers and books).
I have not been involved in CIGRE.

PAC World: You have traveled to many countries. Do you have a favorite place to visit?
R.G.: Sweden and Spain. My friends from ASEA in Sweden are great people. When I go there they are always ready to help in any way.
I lived in Spain for two years and I had a very nice experience there as well. My time with PTI people in Schenectedy has also been very enjoyable and fruitful.

PAC World: What do you like to do when you are not working?
R.G.: I like to read books, and to design power system analysis software.

PAC World: What is your favorite form of entertainment?
R.G.: Music and movies. Classical music is my preference. I am a big Beethoven fan, followed by List and Mozart.

PAC World: Do you have any favorite food?
R.G.: The Mexican food. From different parts of the country. But the salmon in Sweden is also great.

PAC World: Is there a question that we forgot to ask you?
R.G.: None.

PAC World: Do you have a motto?
R.G.: Maybe this is not a motto, but my guiding principles are:
Unlimited curiosity and
The desire to find problems that I cannot solve by myself

I also wish that all my students have the same chance in life that I have had.

There is also some nostalgic feeling, because I am 76 years old and I am trying to get the maximum advantage from the remaining years that I have left.

Power. Flexible. Easergy.
Protecting your electrical assets? today and tomorrow