Analysis of main disturbances at Elettra(A. Pozzer)

-------------------------------------------------------------------------------------------------

Trieste Sinchrotron very sensitive

Voltage Sags

Voltage Peaks

UPS does not for ALL DEVICES

Analysis on the electric system with instruments “Equa”

BEAM LOSSDisturbances

PS or RF Plants off

What can we do?

Signals acquired by Equa:

-3 phases at 380V rms nominal

-1 E-beam current in SR

100mS pre-triggers and 900mS post-triggers

exceed the limit

EQUA Parameters set up:

-min voltage rms level 360V

-max voltage rms level 420V

-max voltage peak level 630V

Equa records the event

If one or more phases

3 phases min rms

E-Beam current SR

starting event voltage Sag

B E A M LOST

A Voltage Sag on three phases caused the lost of beam

Period June 2004 – August 2005

All the runs since 2000

the events with voltage RMS level

the events with voltage PEAK level

Events with MIN and/or MAX voltage RMS level

Tot 112 events 32 of them beam loss

Events distribuition in the course of the seasons

eventi da TEMPORALI

0

10

20

30

run (mese di riferimento)

totali beam dump

events with Beam Loss

eventi da TEMPORALI

0

1

2

3

4

5

6

7

run (mese di riferimento)

n. e

ve

nti

First Consideration: the most difficult period at Elettra is certainly the summer season for the presences of thunderstorms.

summer

summer

summer

Duration – Depth

a) – events with duration < 200mS 26 events

Voltage Sag

E- Beam current

These limits have been observed:

Depth event < 10 % No Beam Lost

Depth event > 15% Beam Lost

Depth event 10% < X < 15%

Unstable situation

b) - events with duration > 200mS

Depth event < 6 % No Beam Lost

Depth event > 6 % Beam Lost

6 events

These limits have been observed:

1) Duration: 500mS - Depth: 8.20%

E – beam SR

Voltage Sag

BEAM LOSS

2) Duration: 500mS - Depth: 5.30% NO BEAM LOSS

E – beam current SR

Voltage Sags

Depth Events < 5% are not considered

Events with MAX voltage PEAK level

Working day in the morning A Voltage Peak

SR in normal condition

E-beam currente SR

Voltage Peak

NO problem

SR is in a particular condition

But If ...

BEAM LOSS

3 events BEAM LOSS

Alwaysduring the Ramping and with E- Beam current > 300mA

Voltage Peak

E-beam currente SR

Example:

Conclusion:

VOLTAGE PEAKS NO big Problems

future? With new Booster?

VOLTAGE SAGSNOT OK - too many Beam Losses

HOPE All Devices

U P S

References:

Effects of mains disturbances on the Elettra operation (R. Visintini – Accelerator Sector Technical Meeting -May,6th 2002)