source: Powering Procedure and Acceptance Criteria for the 13 kA Dipole Circuits, MP3 Procedure, <ahref="https://edms.cern.ch/document/874713">https://edms.cern.ch/document/874713</a>
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Original text: 2020-2021 (Michal); Last corrections: June-2021 (Zinur)
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# 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.
- 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.
In order to perform the analysis of a FPA in an RB circuit please:
1. Select circuit name (e.g., RB.A12)
2. Choose start and end time
3. Choose analysis mode (Automatic by default)
Once these inputs are provided, click 'Find FGC PM entries' button. This will trigger a search of the PM database in order to provide a list of timestamps of FGC events associated with the selected circuit name for the provided period of time. Select one timestamp from the 'FGC PM Entries' list to be processed by the following cells.
**Note that 24 hours is the maximum duration of a single PM query for an event. To avoid delays in querying events, please restrict your query duration as much as possible.**
%% Cell type:code id: tags:
``` python
# Pre-define a time window for search the FPA-events, by default 48 hours from now
Table below provides timestamps ordered achronologically and represents the sequence of events that occurred in the analyzed circuit. Only the first PIC timestamp from the logging DB is reported. Note that for iQPS and nQPS only the very first PM timestamp is reported. Tables with all iQPS and nQPS PM timestamps are presented in the section dedicated to magnet quench protection analysis. The table also contains a time difference in milliseconds from the first trigger event, from the FGC and PIC trigger times.
In short, the following criteria should be kept:
- The PC PM (FGC, lhc_self) timestamp is expected within 1st iQPS PM timestamp +/-40 ms;
- Time delay between PIC and EE at an odd (RR or UJ) point is 100±50 ms;
- Time delay between PIC and EE at an even (UA) point is 600±50 ms;
warnings.warn(f"The time difference between PIC and EE ODD is not within the given range_value {value_range_ee_odd}.PIC :{min(timestamp_pic)} and EE_ODD {timestamp_ee_odd}")
warnings.warn(f"The time difference between PIC and EE EVEN is not within the given range_value {value_range_ee_even}.PIC :{min(timestamp_pic)} and EE_EVEN {timestamp_ee_even}")
Table below contains the reference event timestamps of signals used for comparison to the analyzed FPA. The reference comes as the last succesfull PNO.b2 HWC test.
- Show warning if the two PIC timestamps (ODD and EVEN) differ by more than a 1 ms. (Obsolete)
- If your precision is in ms, the criterion for the RBs (even and odd) of "**1 ms < PIC Timestamp Diff <5 ms**" suits me and sticks with the current PIC capability.
- For all other circuits, as only one PIC is implied to control them, the criterion could be more tightened like "**1 ms <PIC Timestamp Diff <3 ms**"
Regards,
Alain
29/04/2021
%% Cell type:code id: tags:
``` python
rb_analysis.analyze_pic(timestamp_pic)
```
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# 6. Power Converter
## 6.1. Analysis of the Power Converter Main Current
This analysis module displays the main current of the power converter (I_MEAS) compared to the one obtained from the reference FPA (HWC PNO.b2 test with opening of EE systems and without magnet quench).
*ANALYSIS*:
- The evolution of the characteristic time $\tau$ of an exponential decay $f(t)$ is obtained as
Naturally, this formula only applies to exponential decayed characterised by a time constant. Nonetheless, for pseudo-exponential decays, this formula gives a notion of the change of the characteristic time $\tilde{\tau}$. For a circuit we compute the time-varying characteristic time as
- Characteristic time of pseudo-exponential decay of I_MEAS from t=1 to 120 s: 90 s< Tau <110 s
*PLOT*:
- The main power converter current (analyzed and reference) on the left axis, I_MEAS
- The characteristic time calculated for the main current (reference and actual) on the right axis, -I_MEAS/dI_MEAS_dt
The actual characteristic time can contains steps, which indicate a quenching magnet if so (decrease of circuit inductance); note that for the reference one the steps are not present. Timing of PIC abort, FGC timestamp, and the maximum current are reported next to the graph.
- t = 0 s corresponds to the respective (analyzed and reference) FGC timestamps.
|DQAMCNMB_PMSTD |iQPS, DQQDL |100/200 mV |10 ms discrimination |U_QS0 |Old QPS. Detection of quench in one aperture based upon voltage difference between both apertures in same magnet U_QS0 >10 ms above threshold, otherwise discriminator is reset|
|DQAMCNMB_PMHSU |iQPS, nQPS |-|-|-|Firing of quench heaters by quench protection. Generation of PM buffers sometimes happens even if there is no heater firing.|
|DQAMGNSRB (slow sampling rate), DQAMGNSRB_PMREL (fast sampling rate) |nQPS, DQQDS |500 mV * |>20 ms moving average +1 ms discrimination |U_DIODE |New QPS. Detection of quench in both apertures based upon comparing voltage across the magnet (bypass diode) from 3 magnets in same half-cell and one reference from adjacent half-cell. 50Hz notch moving average filter (20ms worst case). The signals in the 2 classes are identical, only the sampling rate differs. The data with the slow sampling rate is no longer generated as they can be found in the logging database. The recording of data is usually triggered during a FPA, depending on current in circuit, and always when a symmetric quench occurs. The PM buffers are only sent if the DQAMGNS crate trips (what ever the reason).PMs are transmitted with 600 s delay from triggering time.|
|DQAMGNSRB |nQPS, DQQBS| 4 mV | >10 s moving average | U_RES |New QPS. Busbar protection. The signal is not compensated for inductive voltage during ramp.|
|DQAMGNDRB_EVEN, DQAMGNDRB_ODD |iQPS, DQQDC |1 mV, 100 mV |1 s |U_HTS, U_RES |Old QPS. Leads protection. U_HTS is for the high temperature superconducting leads, and U_RES is for the room temperature leads.|
|DQAMGNDRB_EVEN, DQAMGNDRB_ODD |iQPS, DQQDB |+200 V | -50 V | U_BB1, U_BB2 |Old QPS. U_BB1 is the total voltage across the sector. U_BB2 is the voltage across the energy extraction in ODD-point (EE)|
|DQAMSNRB |-|-|-|-|Opening of energy extraction (EE) switches during fast power abort (FPA). 2 EE switches per sector. One for "even" points (EE2). One for "odd" points (EE1).|
*: It was 800 mV before LS1. After LS1 we changed it to 300 or 400 mV. During the training after LS1 we increased it to 500 mV.
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## 8.1. Plot of Voltage Across All Magnets (U_DIODE_RB)
*PLOT*:
t = 0 s corresponds to the PM timestamp of the FGC
First plot (global)
- the power converter current on the left axis, I_MEAS
- diode voltage on the right axis, U_DIODE_RB
Second plot (zoom)
- the power converter current on the left axis, I_MEAS
- calculates the current at which a quench occured by finding the timestamp of the current dataframe (i_meas_df) closest to the quench time and the curresponding value of current - I_MEAS_quench
- compute the time difference (in milliseconds) from the first quench - dt_quench
