Ukrainian nuclear power stations reduce output as frequency inthe grid drops

Source: BBC Monitoring Former Soviet Union - Political

Publication date: Feb 15, 2000

Text of report by Ukrainian news agency UNIAN

Kiev, 15th February: On 14th February at 1845 [1645 gmt] the output at all operational nuclear power stations - Zaporizhzhya,Rivne and South-Ukrainian - was automatically reduced as the frequency in the grid dropped below 49Hz, UNIAN learnt at the Ministry of Environment and Natural Resources [as received]. The output at all operational generating sets - No 3, 4, 5 and 6 -of Zaporizhzhya nuclear power station dropped to 90 per cent and was restored [to a normal level] at 1940 [1740 gmt]. Due to the frequency drop, the output of the No 3 generating set of Rivnenuclear power station, the No 1 set of Khmelnytskyy nuclearpower station and the No 3 set of South- Ukrainian nuclear power station was automatically reduced to 90 per cent. The output was restored at 2025 [1825 gmt], 1923 [1723 gmt] and 2100 [1900 gmt]respectively.

Publication date: Feb 15, 2000 ) 2000, NewsReal, Inc.

Link

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-- Carl Jenkins (Somewherepress@aol.com), February 15, 2000

Answers

I do believe the Ukraine is going to be the first country to blackout. I give it two more months at the outside.

-- Guy Daley (guydaley@bwn.net), February 15, 2000.

Wondering what is chicken and what is egg! The 1 Hz drop in grid frequency points to serious overloading of the grid. If they try to battle that with a reduction of power supplied to it, they are at the abyss.

-- W (me@home.now), February 16, 2000.

"The 1 Hz drop in grid frequency points to serious overloading of the grid. If they try to battle that with a reduction of power supplied to it, they are at the abyss." Solution = blackouts. Cut off heavy-consuming areas for a while to drop the demand back to what's tolerable and allow normal service to non-blackout-ed areas. If too many consumers switch on too much demand the power stations have to work harder to satisfy the demand. Every extra Watt of consumer demand feeds back to the turbines and is felt as a slightly increased resistance to push against. This means the torque the turbines are being pushed against increases, and so they can slow down (causing frequency drop and voltage drop in the grid). If this gets too severe or goes on too long the power plant can get physically damaged (not good!) and the whole country's electricity goes off-spec. My guess is the reduction of output from these plants happened when they had to push against the overloading and went back up when somewhere got plunged into darkness. Output only dropped by 10% for one hour.

Disclaimer to what I've just said about power grids: I'm no electrical engineer and probably don't know half as much as I think I do, but that's what I heard once and it seems to make sense based on what I do know about this stuff we call "electricity". Constructive criticism welcome :o)

-- randomdigits (r@r.r), February 16, 2000.

Randomdigits,

You are right with your description of chicken and egg! Abyss in my book is the shedding of load to save the grid. I am an Electrical Engineer. Interesting is that load shedding (USAGE reduction) wasn't mentioned. I think we got a filtered version of the full story.

-- W (me@home.now), February 16, 2000.