An executive of the power company backs out of a trip to initiate studies and assess the viability of tying Puerto Rico’s bulk electric system with a system of a south american country which used to be in war.I volunteer to go. Our mission is to reach an understanding, to start studying the economics of laying  an underwater transmission cable interconnecting both systems.

Everything is going well, presentation after presentation of markets, prices, fuels, etc. On the second day, what I considered the highlight of the trip (for me anyway), a visit to their energy control center, up in the image above.

A mezzanine over the control center gives you a vantage point, an eagle-eye view of everything going on. After their Operations chief recites through what seems the standard spiel, he’s about to end the presentation then I start with specific system operation questions; generation, loads, EMS, frequency bias, ACE, contingencies, SPS’s, UFLS, etc. All my questions are answered very professionally and then, with an very seriously concerned face, “our system is very stable akin to an infinite bus, unlike your island in the Caribbean”.

Before I can recover from what he just said and try to politely answer or not his statement, behind him I happen to notice the ACE going to around +100 MW and the frequency up to about 60.18 Hz. Aha! How often the ACE goes +/- 100? I casually ask and he answers “once a month, maybe”. “Oh, just like right now” I say. That was a too-easy cheap backhand shot I had to take.

As he turns toward the glass pane, the mapboard now has 2 breakers flashing green at one substation and down at the bottom another 2 green flashers…then they all turn solid green so I ask about what just happened.

Takes a look and tells me that two transmission ties with a neighboring country to the south tripped and I know he keeps talking but my attention is already locked in the mapboard and the situation below.

One of the bottom breakers flashes red then goes dark, the same with the other sometime later. (Aha! Lines’ energized)

The big screen to the right of the mapboard  has the transmission alarms summary page up, one of the open breakers turns red then green and I see the fail to operate alarm popping up in the display, this happens twice. Then the exact thing happens with the other breaker…My questions keep coming as if nothing happened:

So, are there any other ties to this country?                                             No

Not even at any other voltage?                                                                No

“Well the breakers in your country are not closing because both areas are out of sync” I, matter-of-fact say.

The operations chief’s face turns cherry red, grabs a flip-phone out of his pocket and angrily barks a couple of instructions to the operators below…while trying not to raise his voice.

The submarine cable project never happened, the economics did not support the investment.