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Majortel Converter 250V dc Operations

September 01, 2017 | Technical Info,

MTD Converter*: 250 Volt Operation

Scope: Application for a Utility Service Provider that will deploy the Majortel DC-to-DC converter in a 250V dc nominal power, substation environment. This procedure is intended to be performed by qualified personnel familiar with general dc electrical system knowledge and maintenance protocols. Multiple 130V to 24 and 130V to 48 converters are deployed across the nation, this is one of a select few that operate with a higher voltage bus.  #SmartGrid #Grid Modernization

Assume: The battery system will likely be a 116 cell installation, therefore the operation range could be:
1) Low voltage 1.75 v/p/c * 116 = 203V
2) High voltage 2.3 v/p/c * 116 = 266.8
Battery installations vary by application. Consult the battery design parameters for definitive operation range.

Engineering Considerations:
a) The input current is 8.4A @ 203V maximum per power module.
b) Worst case calculation is a 20A / 203V dc input rated circuit?
8.4 x 2 = 16.8A per full system. 16.8/.85% = 19.76A input; rounding up to a 20A dc source, protected branch circuit
c) Users shall adjust the Alarm Threshold parameters in the system MTS-Com unit when deployed in a 250V dc environment. Make adjustments for the installation operational requirements by using the parameter setting procedure below. Potentially set the low voltage trigger to 193 (1.67 v/pc) and the high voltage trigger to 284 (2.45 v/pc).
d) The converter will shutdown and auto recover if dc source voltage exceeds the 300V rating. No damage and auto-recovery are module features. With an “Input Over Voltage” rating of 300V dc, no damage occurs because the rated voltage of key internal components is 450V dc.
+  The voltage OFF trigger is X = 300V dc
++   Hysteresis for recovery is X – 10V = 290V dc

Parameter Setting to Commission System:

  1. From main screen: Press ENT or ESC
  2. Press down arrow three times to the SETTINGS selection
    A. Press ENT to input access password
    B. Press ENT to highlight the first # symbol.
    C. Press UP arrow to index up to numeral 2 (or your programmed number)
    D. Press ENT again to confirm numeral
    E. Press DOWN arrow to index right to next # symbol and repeat steps B – E until all four are entered.
    F. Once complete and entered correctly, the menu display will change to administrative settings with the following sub-menu titles.
  3. Select DC LIMITS and the screen will display all necessary parameters for DC input and output voltage alarm thresholds.
    G. Use the UP/DWN buttons to set the desired parameter voltage – trigger point.
    1. Options (range; bold is default):
    * DC OUT HIGH (45-58)
    * DC OUT LOW (42-45-58)
    * DC IN HIGH (100-150-300)
    * DC IN LOW (100-300)
  4. Select a parameter by pressing ENT once (it should change screen cursor color).
    H. Use the UP/DWN buttons to set the desired trigger voltage for the application.
    I.  Press ENT again to confirm the setting.
  5. Press ESC three times to return and view the main menu.

Equipment Models:

*  application note applies to these models


(equipment design intent does not include crane and HVAC applications)

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