Excursion to Gujarat Energy Transmission Company limited
When I switch on the electrical appliances at home, I have always been curious about their energy source. Through the school textbooks I have gained knowledge about energy generation through thermal, wind, hydro, nuclear, solar power plants and electricity transmission; however, I have desired to witness this energy transmission in real life and learn
about the distribution process and its difficulties in the actual world. This inquisitiveness lead me to visit the GETCO 220kV Nyara substation in Rajkot during my summer vacations in 2013. I approached my uncle, a junior electrical engineer at GETCO, to attain permission to visit the substation in August of the same year.
After receiving the consent, I set on the journey to the substation which was about 16 miles from my residence in the city. The drive itself was enjoyable as I witnessed the gradual accumulation of the transmission conductors amidst the gentle downpour and beautiful landscapes. Upon reaching the substation, I was overwhelmed by the handsome scenery of the transmission circuits. Never before had I visited the industrial region in the country and witnessed the huge electrical instruments in close vicinity. In the subsequent minutes I was briefed about the safety regulations, exit routes and offered a hard hat. After the safety briefing and the introduction, I was guided by a plant operator towards the switch yard. This yard was where most of my questions were answered because I could receive first-hand information about energy distribution and witness it simultaneously. According to the information given by my guide (the plant operator), the input 220kV transmission lines for the substation mainly originated in Tebhada and Hadala in Gujarat, where 400kVtransmission was stepped down to 220kV for output distribution. I then spotted the 220kV Main Bus I and II that comprised of 6 input transmission lines originating in Hadala (2), Tebhada (2), Jetpur and Kangashiyali.
After this we visited the quarter of the field where the 220/132 kV and 220/66 kV step down transformers were situated. To my amazement, these transformers neither resembled the ones depicted in my school Physics textbooks nor the ones in “Transformers: Dark of the Moon” (movie released in 2011). However, I could recognize their working principle that I was taught in my classroom. Since these were step-down transformers, their primary voltage was greater than their secondary voltage and the number of turns of the primary coil was greater than those of the secondary coil. Consequentially, I visited many more sites where step-down transformers were situated (manufactured by APEX Electricals Limited, Baroda, India) and discerned their sequential relegation in potential difference from 220kV to 66kV to 11kV to 440V to finally 220V which was for the substation’s regular use. For output distribution, the transmission circuits were only of 66kV (9 lines) to regions of Raiyadhara, Metoda, N’pipaliya, Navagam (2), Taraghadi, Popatpara, Ghanteshwara (2) and 132kV (2 lines) to Vajadi and Vikram regions.
As these transmission cables constituted circuits, the terminology reminded me the circuit diagrams in my school books. However, I couldn’t observe any switch or fuse in the circuits that surrounded me in the yard and wondered how those transmission cables were separated in emergencies. Upon questioning my
substation guide, I was informed about transmission breakers/isolators that performed the function of switches on larger scales. These circuit breakers were operated from the control room. Later I was ushered into the above mentioned control room where I was flabbergasted by the accretion of monitors, indicators and instrumentation appliances.These appliances were controlled by microprocessors that were programmed to notify any abnormalities through alarms. I found the atmosphere in the room very intriguing as there was too much to learn in very little time. I spent an entire day at the substation and tried to adjust to the schedule of the plant operators, while learning a lot from the entire experience of organising and monitoring critical statistics. It was very fascinating to observe all the mechanisms of recording the readings from the appliance monitors, check for any anomalies and then communicate the recorded data to the authorities through telephone hotlines. Meanwhile I tried, to the best of my comprehension ability, to absorb knowledge from the substation operators who were busy analysing and organising the recorded information. After learning about information gathering through equipment notifications, safety alerts, online reports, power consumption statuses and efficiency updates, I then learnt about information sharing between substations. Through this subject of information sharing, I was introduced to relays and SCADA (Sequential Control And Data Acquisition) system. We visited the storage area of the substation where relay batteries were stacked and also the room with the RTU panel relays. I was informed that these RTU panel relays were used for communicating information between substations and also controlling related mechanisms. Then I was introduced to the improvised communication technique of SCADA, through which I could observe graphic representations of transmission circuits (that included symbolic transformers, transmission conductors, bus bars etc.) and also the vital parameters of these transmission devices. I could correlate the scenes I observed that morning in the switch yard with their graphic depiction on the screens I was observing in the control room. The operators then explained the systems through which electricity was provided to the national borders and the relevant importance of SCADA and other communication arrangements. Gradually the clock shifted its needles as I remained lost in recording the monitored data in an excel sheet and learning about the sources that satisfied the energy demands of Gujarat state. After those absorbing conversations with the engineers present in the room about electricity generation and its economics, I bid adieu to the substation where I gained knowledge about industrial mechanisms in my field of interest…