<h1><center>Analysis of a PNO.D16 HWC Test in an IT Circuit</center></h1>
The main quadrupole magnet circuits of the 8 Inner Triplet (IT) systems in the LHC are composed of four single aperture quadrupole magnets in series and have a particular powering configuration, consisting of three nested power converters (PC), see Figure below.
Main quadrupole magnet circuit of the Inner Triplet system for IT’s at points 1 and 5 (left) and IT’s at points 2 and 8 (right).
Note that the configuration for the IT’s in points 1 and 5 is different from the configuration in points 2 and 8. An earth detection system is present at the minus of the RTQX2 converter. Detailed information concerning the converters is given in EDMS 1054483. Note that the currents in the quadrupole magnets are given by:
\begin{equation}
I_\text{Q1} = I_\text{RQX} + I_\text{RTQX1} \\
I_\text{Q2} = I_\text{RQX} + I_\text{RTQX2} \\
I_\text{Q3} = I_\text{RQX} \\
\end{equation}
The two magnets Q1 and Q3 are type MQXA and the two combined magnets Q2a and Q2b are type MQXB. Q1 is located towards the interaction point.
Note that the IT’s at points 2 and 8 have a slightly higher nominal operating current than the IT’s at points 1 and 5, see Table 1.
The aim of this test is to calculate the splice resistances, check the regulation of the current leads, and verify the correct functionality of the PC when a powering failure is generated. The currents are equal to 90% of the nominal current in the RQX, RTQX1, and RTQX2 converters, see figures below.
|MP3|Check margin between U_RES and the QPS threshold|U_RES < 30 mV for both boards at the start of the PC fault|
source: Test Procedure and Acceptance Criteria for the Inner Triplet Circuits in the LHC, MP3 Procedure, <ahref="https://edms.cern.ch/document/874886/2.1">https://edms.cern.ch/document/874886/2.1</a>
%% Cell type:markdown id: tags:
# Analysis Assumptions
- We consider standard analysis scenarios, i.e., all signals can be queried. Depending on what signal is missing, an analysis can raise a warning and continue or an error and abort the analysis.
- In case an analyzed signal can't be queried, a particular analysis is skipped. In other words, all signals have to be available in order to perform an analysis.
- It is recommended to execute each cell one after another. However, since the signals are queried prior to an analysis, any order of execution is allowed. In case an analysis cell is aborted, the following ones may not be executed (e.g. I\_MEAS not present).
# Plot Convention
- Scales are labeled with signal name followed by a comma and a unit in the square bracket, e.g., I_MEAS, [A]
- If a reference signal is present, it is represented with a dashed line
- If the main current is present, its axis is on the left. Remaining signals are attached to the axis on the right. The legend of these signals is located on the lower left and upper right, respectively.
- The grid comes from the left axis
- Title contains timestamp, circuit name, signal name allowing for re-access the signal.
- The plots assigned to the left scale got colors: blue (C0) and orange (C1). Plots presented on the right have colors red (C2) and green (C3).
- Each plot has an individual time-synchronization mentioned explicitly in the description.
- If an axis has a single signal, change color of the label to match the signal's color. Otherwise, the label color is black.
A quench in the superconducting circuits is detected and all the quench heaters are fired as soon as one of the following signals exceeds the threshold.
|tt893_nxcals_dfs |list of DataFrames |K |NXCALS|Temperature at the top of the current lead, TT893.TEMPERATURECALC|
|tt891a_nxcals_dfs |list of DataFrames |K |NXCALS|Temperature between the HTS and resistive part of the current lead, TT891A.TEMPERATURECALC|
|u_res_nxcals_dfs |list of DataFrames |V |NXCALS|Voltage of the resistive part of even and odd leads, U_RES|
|u_hts_nxcals_dfs |list of DataFrames |V |NXCALS|Voltage of the HTS part of even and odd leads, U_HTS|
|cv891_nxcals_dfs |list of DataFrames |% |NXCALS|Valve for regulation of TT891A, CV891.POSST|
*CRITERIA*
- Check if the temperatures TT893 at the top of the copper part of the four current leads, which must be over dew point, but not overheated: 285 K < TT893 < 305 K, even without current
- Check if the temperatures TT891A at the top of the HTS part of the four current leads, which must be regulated around 50 K: 46 K < TT891A < 54 K, even without current
- Check if the voltages U_RES over the copper part of the four current leads, which, at constant current, must stay constant (no drift) and ABS(U_RES) < 65 mV at 11.0 kA or 70 mV at 11.8 kA
- Check if the voltages U_HTS over the HTS part of the four current leads,which must stay below 50% of the threshold: ABS(U_HTS) < 0.5 mV
- Check if the valve opening regulating the helium flow along the top of the HTS part of the four current leads, which should never be blocked/saturated at its minimum/maximum.
A current cycle up and down from I_MIN_OP to I_INJECTION is performed with a short plateau (typically 10 minutes) at highest current. The aim of this test is to check the magnet performance and the QPS calibration at that current level. The current to earth and the current error from the power convertor are checked during the sequence.
The required analysis and signatures are listed below.
|Responsible|Type of analysis|Criterion|
|-----------|----------------|---------|
|MP3|Splice signals|U_res < 500$\mu$V if the inductive voltage of the bus-bar segments is compensated|
|-|Automatic analysis on earth current and error current|I_EARTH_PLI1_A2 < I_EARTH_MAX and I_ERR_PLI1_A2 < I_ERR_MAX|
source: Powering Procedure and Acceptance Criteria for the 13 kA Dipole Circuits, MP3 Procedure, <ahref="https://edms.cern.ch/document/874713/5.1">https://edms.cern.ch/document/874713/5.1</a> (Please follow this link for the latest version)
%% Cell type:markdown id: tags:
# Analysis Assumptions
- We consider standard analysis scenarios, i.e., all signals can be queried. If a signal is missing, an analysis can raise a warning and continue or an error and abort the analysis.
- In case a signal is not needed for the analysis, a particular analysis is skipped. In other words, all signals have to be available in order to perform an analysis.
- It is recommended to execute each cell one after another. However, since the signals are queried prior to analysis, any order of execution is allowed. In case an analysis cell is aborted, the following ones may not be executed (e.g. I\_MEAS not present).
# Plot Convention
- Scales are labeled with signal name followed by a comma and a unit in square brackets, e.g., I_MEAS, [A].
- If a reference signal is present, it is represented with a dashed line.
- If the main current is present, its axis is on the left. Remaining signals are attached to the axis on the right. The legend of these signals is located on the lower left and upper right, respectively.
- The grid comes from the left axis.
- The title contains timestamp, circuit name, and signal name allowing to re-access the signal.
- The plots assigned to the left scale have colors: blue (C0) and orange (C1). Plots presented on the right have colors red (C2) and green (C3).
- Each plot has an individual time-synchronization mentioned explicitly in the description.
- If an axis has a single signal, then the color of the label matches the signal's color. Otherwise, the label color is black.
