Avtron K922A, Manual

Page: 43 / 90

Peak Load Voltage Rating
Avtron Outdoor Resistive Load Bank • Part Number K922AD41523
A-1
ADDENDUM
PEAK LOAD VOLTAGE RATING
In the high voltage mode, the Load Bank is rated for 13.8 kV operation. There are several factors
which influence the peak voltage rating and need to be reviewed in conjunction with each other. The
Load Bank, as designed, can be operated at load voltages to 14,100 VAC with a peak voltage of
14,400 VAC if operation is conducted under specific parameters. The following twelve items are the
primary operational criteria which require review prior to operation above 13,800 volts:
1.
Verify all sources of power are removed from unit. A physical inspection of insulation
system, termination, cooling devices, clearances and load cable support structure are
required. This should be conducted by a qualified technician or personnel familiar with this
type of medium voltage apparatus. A high potential test can be conducted; consult factory for
test voltage and acceptable leakage rate.
2. The Load Bank must be in an ambient of 95°F or less and intake air must be less than 104°F
even under over voltage operation.
3. In extremely cold climates, follow special instructions in PREPARATION FOR USE
section.
4. Excess moisture and surface contamination are a primary concern. Prior to operation, the
heaters need to be energized (not less than 30 minutes) to drive off moisture in the
control/contactor area. When possible, the Load Bank should be operated at rated or a
reduced load voltage for a minimum of five minutes to assure moisture has been evaporated.
Operation during high humidity levels (RH) during over voltage testing should be avoided.
5. The insulation system, load conductors, termination, Glastic panels and every medium
voltage current carrying component within the Load Bank must be clean and track free.
Verify that there is no corrosion on bus or bare terminals. Check for tracking and
contamination build-up (especially on horizontal surfaces). The primary limiting factor for
the over voltage rating is the load conductors. This cable is rated to 13.8 kV. Medium
voltage cable will tolerate higher voltages but, depending on the application and
environmental conditions, may stress the insulation. Verification of cable clearances, phase
to phase, and phase to ground are more critical during over voltage testing. Since cable may
shift during transit or by other means, inspect all medium voltage load cable routing prior to
operation.