Reports 1-1 of 1 Clear search Modify search
AdV-COM (AdV commissioning (1st part) )
Paoletti, D'Andrea, Fiori, Nocera - 16:29 Friday 15 September 2017 (39487) Print this report
Tests on IPS Mains under DIESEL generator (second test)

As reported in 39431 we tried to move also CEB under DIESEL generator, but the test failed.

Yesterday we have tried again and everything has worked fine.

The test aim to understand the origin of the 50Hz peak (and sidebands) in Dark Fringe; the procedure is:

1) cut off the standard ENEL IPS mains (that supply power to CEB and also MCB); all IPS loads are OFF (e.g. Air Conditioning Systems), and the Interferometer's mains is generated by UPS systems working on batteries.

2) after some minutes, give back the IPS using DIESEL generators, that by their mechanical nature are not able to create a precise 50Hz frequency.

If, between (1) and (2) the 50Hz peak remain more or less the same, we can say that the "source" is the UPS line in CEB (and MCB).

This is what happened during the test: while the ITF was under UPS alone (all IPS systems OFF) the peak in Dark Fringe have the same height as before and a slight difference in frequency.

Moreover, because the UPS system "follow" the IPS that see on its input, and because this IPS is then generated with DIESEL motor after (2), the UPS mains will move in frequency; this test was done at terminal buildings in the previous entry (39431), leading to the conclusion that NEB and WEB have little impact on the 50Hz seen in Dark Fringe. This test done now in CEB show a clear correlation between the "new" DIESEL-generated IPS and the Dark Fringe.

In fig.1 the GREEN curves are the standard situation, RED curves are when IPS is OFF, and BLUE curves are when IPS come back under DIESEL generators.

In fig.2 there is a spectrogram where a clear correlation is visible between UPS (while frequency-driven by DIESEL generators) and Dark Fringe.

In fig.3 there is the COHERENCE plot between UPS  and Hrec (GREEN when in standard condition, BLUE when under DIESEL generators); worth noticing that at the precise 50Hz value there is a loss of Coherence when under Diesel; this can be explained because terminal buildings (NEB and WEB) were still in standard condition during this test, and we know their coupling to be a factor ten less in Dark Fringe.

Conclusions: it seems the 50Hz line in Dark Fringe comes mostly from CEB UPS mains system.

Note: every time the IPS come back to MCB, the ITF unlock; this happened in the past, and will happen every time there is a power loss. UPS supply all the ITF, but the ITF unlock when IPS come back. This has to be cured!

 

Here the timetable of the tests (all times are Local Time):

 

Sep14,17-14:07:39 -> GPS: 1189426075

ITF locked (high microseism)

 

Sep14,17-14:17:38 -> GPS: 1189426674

CEB IPS OFF

 

Sep14,17-14:24:41 -> GPS: 1189427097

CEB DIESEL start

(ITF immediately unlocked due to MCB glitches)

 

Relock leaving CEB DIESEL ON

 

Sep14,17-15:18:34 -> GPS: 1189430330

ITF locked DC readout (15MPC)

Sep14,17-15:26:45 -> GPS: 1189430821

LowNoise_3 (but with bad sensitivity)

Sep14,17-15:28:43 -> GPS: 1189430939

25MPC

Sep14,17-15:29:56 -> GPS: 1189431012

27MPC

 

Sep14,17-15:37:34 -> GPS: 1189431470

NEB DIESEL is ON

 

Sep14,17-15:39:18 -> GPS: 1189431574

NEB MT (Medium Voltage 15kV) is OFF, NEB is under DIESEL

(150Hz grow in Hrec)

 

Sep14,17-15:45:37 -> GPS: 1189431953

WEB DIESEL is ON

 

Sep14,17-15:48:11 -> GPS: 1189432107

WEB MT (Medium Voltage 15kV) is OFF, WEB is under DIESEL

 

(from now on, all VIRGO is under DIESEL GENERATORS)

 

Sep14,17-15:59:25 -> GPS: 1189432781

NEB MT (Medium Voltage 15kV) is ON, NEB DIESEL is OFF, standard conditions for NEB

(150Hz still high in Hrec)

 

Sep14,17-16:05:30 -> GPS: 1189433146

WEB MT (Medium Voltage 15kV) is ON, WEB DIESEL is OFF, standard conditions for WEB

 

(from now on, only CEB and MCB are under DIESEL GENERATORS)

 

Sep14,17-16:10:30 -> GPS: 1189433446

CEB and MCB MT (Medium Voltage 15kV) is ON but but not yet connected

 

Sep14,17-16:11:09 -> GPS: 1189433485

CEB and MCB MT (Medium Voltage 15kV) is CONNECTED (DIESEL still free running to cool down, for about 180 seconds from now) – ITF unlocked again due to MCB glitches

 

END of TESTS

Images attached to this report
Search Help
×

Warning

×