Eaton 600 A 25 kV class PUSH-OP Installation, Operation And Maintenance Instructions

Preventive maintenance tapping
Preventive Maintenance Tapping (PMT™) will automatically
operate the tap-changer based upon user-configured
parameters. Under certain operating conditions and load
tap-changer contacts can become susceptible to coking. The
PMT feature will operate the tap-changer to wipe the
contact blades and prevent build-up of carbon. There are
two different types of preventive maintenance tapping
available: PMT Mode A and PMT Mode B.
PMT Mode A
When enabled the control monitors tap position and, if it
stays on any single tap position for a user-defined period of
time (Time Delay, FC 302), the control will automatically
raise the tap-changer one position, lower the tap-changer
two positions, and then raise the tap-changer one position.
When PMT Mode A is performed on a Quik-Drive™ tap-
changer, this entire operation will take approximately one
second. The user can monitor how much time is left prior to
the maintenance tapping being performed at Countdown
Delay, FC 301. To sample how the PMT Mode A functions,
the user can use Issue Test, FC 303.
PMT Mode B
When enabled, the control monitors tap position and, if it
does not pass through neutral for a user-defined period of
time (Time Delay, FC 322), the control will automatically tap
through and past neutral one position. This operates and
wipes the blades of the reversing switch. It then returns the
tap-changer to the original tap position. Due to the possible
large fluctuation in voltage while maintenance is being
performed, there are more configuration points in PMT
Mode B than in Mode A. The user can determine the time
of day that PMT Mode B is allowed, so that maintenance
can be performed at night. To limit the amount of allowable
voltage-swing when performing maintenance, the user can
input the maximum deviation. Also, the user can input a
current limit so that maintenance is only performed under
light load conditions. Additionally, a master slave mode is
available so multiple units can act at once to keep the
supply balanced for three-phase loads that are sensitive to
imbalance. The user can monitor how much time is left prior
to the maintenance tapping being performed at Countdown
Delay, FC 321. To sample how the PMT Mode B functions,
the user can use Issue Test, FC 328.
Duty cycle monitor
The Duty Cycle Monitor calculates the amount of life used
for each arcing surface contact on the voltage regulator
Quik-Drive tap-changer. The control uses the metering
values, such as current, voltage, power factor, and tap
position, and a detailed data on the internal design of the
voltage regulator to calculate the interrupting current and
recovery voltage. This is then related to the test data for the
appropriate Quik-Drive tap-changer. The Duty Cycle Monitor
functions only on voltage regulators with a Quik-Drive tap-
changer.
FC 333 displays the worst-case value of life used, expressed
as a percentage, to the third decimal point. This value may
be used to generate two different Data Alarms. The first
DCM Data Alarm is intended to be configured to that
maintenance may be scheduled. The suggested setting is
75%. The second Data Alarm is intended to be set at a
higher level, suggested setting of 90%, to notify the user
that a service outage due to contact failure may be
imminent. For more information on Alarms, see Alarms in
this section of the manual.
A detailed percentage of life-used for each arcing contact is
available ProView NXG software. When replacing a control
on an existing voltage regulator, ProView NXG software
must be used to enable and configure the Duty Cycle
Monitor feature. Configuration values programmed in the
software for the specific voltage regulator include the
design number and an estimation of the amount of life
already used.
Note: Duty Cycle Monitor is active only on regulators from
Eaton with Quik-Drive tap-changes.
Leader/follower scheme
The Leader/Follower scheme is an electronic scheme
designed to keep two or three individual single-phase step
voltage regulators on the same mechanical tap position. This
is primarily used by utilities and others needing three-phase
voltage regulation at the expense of a balanced load voltage
center with unbalanced loading. A fiber optic intelligent loop
scheme is used between controls providing the
communications necessary between phases to initialize a
tap change and provide positive feedback in maintaining
those equal tap positions. As a result of the
communications between all phases, access to certain data
from all phases is available at the display of all controls
involved as well as with ProView NXG software.
This scheme can also be used for paralleling substation
voltage regulators with a set of power transformers used for
increasing capacity and providing a backup for maintaining
regulated power. For more details, see Service Information
MN225023EN Leader/Follower scheme Installation and
Operation Guide.
101
CL-6 SERIES CONTROL INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN225016EN January 2016

Eaton 600 A 25 kV class PUSH-OP Specifications

General

Brand	Eaton
Model	600 A 25 kV class PUSH-OP
Category	Cables and connectors
Language	English