Power Supply and Protection System Toroidal Magnets FAQ

. [se del caso - Per gli operatori economici non residenti e privi di stabile organizzazione in Italia] si impegna ad uniformarsi, in caso di aggiudicazione, alla disciplina di cui agli articoli 17, comma 2, e 53, comma 3 del d.p.r. 633/1972 e a comunicare a DTT la nomina del proprio rappresentante fiscale, nelle forme di legge;
. [if applicable - For non-resident economic operators without a permanent establishment in Italy] undertakes to comply, in the event of award, with the provisions of Articles 17, paragraph 2, and 53, paragraph 3 of Presidential Decree 633/1972 and to notify DTT of the appointment of its tax representative, as required by law;
Could you confirm that this article is not applicable for a company located in EU member state?
In case it does, could you please explain why.

(Lotto 1 e Lotto 2) In questo caso, l’obbligo di avvalersi del rappresentante fiscale Iva non sussiste in quanto le operazioni effettuate sono direttamente qualificabili come acquisti o cessioni intracomunitari tra le parti contraenti, si applicherà il reverse charge versando direttamente l’iva.
Pertanto la vostra interpretazione è corretta.
In this case, the obligation to make use of the VAT tax representative there is no, since the operation carried out can be directly qualified as intra-community EU purchases or transfers of goods between the contracting parties, the reverse charge will be applied by paying the VAT directly.
Therefore your interpretation is correct.

Al paragrafo 5.18 (demineralized water cooling system) di pagina 21 è riportata la seguente frase:
“Internal closed-loop demineralised water cooling, provided by the IS and connected through heat exchangers to the DTT technical water-cooling system, shall be adopted”.
Al paragrafo 5.28.4 (interfaces with the site water cooling system) di pagina 30 è riportata la seguente frase:
“DTT will provide technical cooling water and demineralised cooling water for aluminium components”.
È possibile avere conferma che per il raffreddamento di componenti in materiale diverso dall’alluminio è possibile utilizzare acqua non demineralizzata (indicata come technical cooling water), allacciandosi direttamente al DTT technical water cooling system senza l’utilizzo di uno scambiatore di calore e senza l’utilizzo di un circuito in ciclo chiuso interno?

(Lotto 1 e Lotto2) Si conferma che per il raffreddamento di componenti che non necessitano di acqua demineralizzata è possibile utilizzare l'acqua tecnica e non essendo demineralizzata si potrebbe fare a meno di un cicuito di raffreddamento chiuso; ma sarebbe preferibile per motivi di responsabilità tra DTT ed IS avere un unico punto di interfaccia che fisicamente separi il circuito di raffreddamento della TFPS (sotto responsabilità IS) da quello di adduzione (responsabilità DTT). Si tenga presente infine che tutti i test di isolamento in fabbrica e in sito devono essere soddisfatti pienamente.

Dummy Load (3)
According to our simulations the expected ripple will be in the order of tens of mA pp with a single TF coil, which is well below your ripple requirement of +/-0.1% (85 A pp) for a 48 mH load.
Please note that some key parameters of the TFPS have been set by the specification; at least 12 pulse rectifier (this requires line reactors), no load secondary voltage of the transformer, short circuit voltage of the transformer… With these parameters the output DC voltage (with load) is about 80 V so the maximum dummy load resistance for 42.5 kA is 80/42.5 kA = 1.8 mOhm. The challenge is manufacturing a normal conducting coil of 2mH with a 1.8 mOhm resistance.
As the current ripple on a 2mH load only varies from 4-5A pp with different load currents (from 10 to 42.5 kA)
Can the factory acceptance test be performed on a dummy load of 2mH at a lower current, between 10 and 15 kA, and complete the acceptance with calculations and simulations.”?

(Lotto 1) Yes, your proposal can be accepted peforming test for current ripple on a dummy load of 2mH at a lower current, between 10 and 15 kA, and to complete the acceptance with calculations and simulations.

(Lot 2)
Concerning § 7.2.2 of the Technical Specification (Factory Type Test on SCB):
"4) Test to verify the current interruption capability of the SCB":
Although the current of 47 kA is actually about 10% higher than the nominal FDU current, if Non-linear Dump Resistors are used the reapplied max voltage might result lower than indicated (Vnom +10%). Is this acceptable?
Regarding the interval of 30 minutes: this is ½ of the nominal repetition rate. This procedure, adds to the increase in the current and might bring to unwanted thermal build up, in a structure designed to operate every 60 minutes. May this interval be exactly defined during DDP?

(Lotto 2)
1) For the former question: Yes it is acceptable.
2) For the last one: Yes as I said: we can discuss this point in a deeper way during DDP.

(Lot 2)
Concerning § 7.2.2 of the Technical Specification (Factory Type Test on SCB):
3) Test to verify the electro‐dynamic resistance of the mechanical assembly.
SCB can be made of Press-Pack devices, which should not be clamped, unclamped and clamped again to avoid possible permanent damages to the pressure contacts. In this case we propose to perform this test with a dummy branch equipped with conductive blocks, BEFORE the final mounting of the actual stacks.

(Lotto 2) Yes.

(Lot 2)
Concerning § 7.2.2 of the Technical Specification (Factory Type Test on SCB):
"2 Test to verify the ?2? capacity of the SCB: The Static CB shall be supplied with a direct current of 53kA dc for a time at least longer than the BPS opening time multiplied by 1.25 without performing current interruption. The test shall be repeated 10 times with a delay of 30 minutes between two consecutive tests."

Question: the delay of 30 minutes might bring to unwanted thermal build up, in a structure designed to operate every 60 minutes. Could you please comment?

(Lotto 2)
A time of 30min was a quite reasonable time, seen that the test shall be repeated 10 times. Your proposal means that the duration of test is 10 hours instead of 5 hours. I think we can discuss this point in a deeper way during DDP.
For the purpose of submitting the technical proposal it is almost irrelevant.

Concerning § 7.2.2 of the Technical Specification (Factory Type Test on SCB):
"1) TFC FDU and mock‐up: A direct voltage equal to the nominal value plus 10%, with duration of 1 minute shall be applied to the turned‐off Static CB. The test shall be repeated 3 times for each polarity."

We have three questions:
a) When SCB opens, the voltage of 5.2/5.5 kV appears for a time of some seconds across the SCB, and then decreases as the current in Dump Resistors goes to zero. Snubber and clamp resistors are designed in energy for this duty. May them be disconnected during this test lasting 60 seconds?
b) According to fig. 7 of TS, FDU are designed for unidirectional current flow. So the voltage at SCB opening develops in one polarity only. Is this correct? If yes, in our opinion the test voltage shall not be reversed
c) Does this holds for the Mock-up too?

(Lotto 2)
a) Yes for FAT, no for SAT.
b) Yes, it is correct there is only one polarity.
c) Yes.

(Lot 2 - FDU)
Acceptance Tests, ref. § 7.2.4 and § 7.3.4;
if NonLinear Dump Resistors are adopted:
a) Measurement of the nominal resistance:
with NonLinear resistors the resistance at 20 °C has no relationship with the voltage across the DR.
If the Dump Resistors are made of N elements in parallel, we assume that the test should verify that with a current of 42,5 kA / N, the voltage across the element should be not greater than 5,2 kV. Is this correct?
b) Test to verify the rated energy:
we assume that when the nominal energy is adiabatically dissipated into an element of them, the tests are satisfied if no mechanical deformation occurs on the tested element. Is this correct?
c) Test to verify the electro‐dynamic resistance of the DR:
we assume that if one DR is made up of N elements in parallel, this test can be carried out on one of these elements at a current of 53 kA / N; this also to agree on a test that is feasible with the available testing setup. Is this correct?

(Lotto 2)
a) It is correct.
b) No. In this case the test shall be performed on one module (composed by N. elements in parallel) because I need to verify the current sharing and temperature distribution among elements i.e. by a thermocamera.
c) No. In this case the test shall be performed on one module (composed by N. elements in parallel) because current sharing in a given branch can be much different and cause a damage. If you are not able to perform this test internally you need an external facility/laboratory where you can perform the test (this in phase of offer must be declared).

(Lot 2 - FDU)
regarding the Dump Resistors for the Mock-up, maximum voltage is 3,6 kV (instead of 5,5 kV), and maximum current is 42,5 kA (as in FDUs). However, the maximum energy of DR of the Mock-up is not specified.
Starting from the max energy of 710 MJ for the DR of the FDU, can we assume that the max energy in this case is 710 MJ x (3.6 kV / 5.5 kV) = 465 MJ ?

(Lotto 2) No, for the DR of Mock-up the max energy to be dissipated is reported in Table 30 of TS = 183,09 MJ (for PF1/6).

(Lot 2 - FDU)
Seismic test:
we see in the Technical Specification the following indications:
on § 7.2.8 4): "Test to evaluate the seismic resistant design of the components of the FDU: The natural frequency of equipment composing the FDU unit shall be measured and shall be higher than 20 Hz."
on § 11.2: "FDUs shall be manufactured based on class B standard; … they shall be designed following the guideline for seismic resistant design for power supply equipment of IEC68‐3‐3 standard."
We understand that the design must be according to these requirements, but it is not clear to us if seismic TESTS are required; if yes, which kind of tests and on which FDU equipment?

(Lotto 2) As reported in section 11.2 and 7.2.8 bullet point 4 (Whole Fast Discharge Unit), the seismic tests are mandatory they are type test and shall be performed on the entire FDU and hence on all components (I think separately on BPS/SCB and on DRs, but depends on total weight) during DDP we will decide if to apply this test only on mock-up (prototype) or only the first FDU. This can depend on if there is a different weights distribution between mock-up and first FDU.

((Lot 2 - FDU)
>From Technical Specification at § 4.1 we understand that only the mock-up will be installed in the FCCTF.
>From this and from § 11.1 we deduce that for the Pyrobreaker the max magnetic field will be less than 10 mT (i.e. not 100 mT).
Is our understanding correct?

(Lotto 2) 1) Yes I confirm that only mock-up (prototype) will be installed in the FCCTF. Further the mock-up will not have the pyrobreaker.
2) In Section 11.1 The magnetic field in these areas, related to the DTT operation, will be less than 10 mT. Whereas for FCCTF area magnetic field will be in the range of 20 – 100 mT at about 4 m of distance from the cryostat and for type of coil. Finaly for pyrobreaker the magnetic field is less than 10 mT.
This means that in the building n. 184 (where 3 FDUs completed by pyrobreaker will be installed) the aspected value of magnetic field is 10mT whereas in the FCCTF (where mock-up will be installed) the aspcted value of magnetic field is much higher 20 – 100 mT. Thus noly for mock-up shall be put in place mitigation actions to reduce the effect of higher magnetic field.

(Lot 2 - FDU)
>From Technical Specification at § 7.4 we read:

"1) Tests to verify the voltage to ground insulation:
For the test of the TFC FDUs a voltage of 5,5 kV in according to IS’s design kV rms 50Hz shall be applied for 10 minutes;…"

We don't understand which is the voltage level to be applied for 10 minutes (probably there is a typo).
Could you please clarify?

(Lotto 2) As reported in Section 7.4 and also in table 31, the voltage value to be applied for the on-site test is 5.5kVac-50Hz-10min