Presentation Voltstick in medium voltage

electrical education

1. VOLTSTICK TM

2. APPLICATIONS
Measure & Evaluate Splices on T & D conductors
Verify closing resistance of normally open switches
Check taps and jumpers for connection reliability
Indicate the aging of connections
Direct measurement of connection reliability
Predict failure to prevent future damage

3. VOLTSTICK
VoltstickSensorin joint
Capacitive cable in line

4. MEASUREMENTS
Crimped Splices
Automatic Splices
Knife Type Switches

5. MEASUREMENTS MYTHS
There are multiple resistors in series for every
splice or switch. (Conductor, Connector Body, &
Connector Interface)
The object is to measure all of the resistors that
can change over time and limit the resistors that do
not change.
Long probes average in the bad connector interface
with the unchanging resistance of conductors and
connector bodies and can hide a defective
interface.
The probe is not long enough to bridge from
one end to the other of the splice or switch

6. MEASUREMENTS MYTHS
There are multiple resistors in series for every
splice or switch. (Conductor, Connector Body, &
Connector Interface)
Measuring in the same locations on the device is
critical to making repeatable measurements
It is difficult for flexible probes to make repeatable
measurements
Safety can be an issue depending on the length of
the flexible probe
A flexible probe would make it easier to make
some measurements

7. CRIMPED SPLICES
MEASUREMENT ISSUES
Every Crimped Splice consists of 3 resistors in series
1.The conductor
2.The connector
3.The interface between the conductor and connector

8. MEASUREMENT ISSUES
The interface is the only resistor that changes
over time
The object is to measure as little of the
conductor & connector as possibleand all of the
section that surrounds the interface

9. MEASUREMENT ISSUES
A good way to make reliability judgments about
a connector is to compare the resistance of the
connector assembly to the conductor
This ratio allows you to compare measurements
on connectors of various sizes

10. TO MAKE ACCURATE
MEASUREMENTS OF THE
CONDUCTOR
Push the button to turn on the Voltstick
The probe has a fixed length and will allow the
Voltstickto make comparisons to measurements
of the splice assembly
Hold the Voltstickin place for at least 5 seconds
Place other probe/ capacitiveon the conductor
Place the bare conductor on the probe at the bottom of the Voltsensor
Line Left Side Right Side
voltstickCapacitive
cable
voltstickCapacitive
cable
Capacitive
cable
voltstick

11. Lets Review the Ratios
Divide the Voltmeter
of each side of the
splice by the
resistance of the line
Line/Left side= see table
Left Side Ratio
Line/Right side= see table
Right Side Ratio
Line Left Side Right Side
voltstickCapacitive
cable
voltstickCapacitive
cable
Capacitive
cable
voltstick

12. RECOMMENDATIONS
Resistance ratio Conditionof fitting Action
0.3 to 1.0 Normal connection None
1.01 to 1.2 Serviceable Re-inspect in one year
shows deterioration. or after next fault
Overloads & faults may
deteriorate the connection.
1.21 to 1.5 Serviceable, poor. Re-inspect in 6
Overloads & faults months, or after
may deteriorate the next fault
connection.
1.51 to 2.0 Serviceable, very poor Schedule replacement
High loads, overloads, in less than 3 months
or faults may deteriorate
the connection.

13. Note: This information was developed from field measurements, manufacturer data, lab
tests, failure analysis, and understanding of deterioration mechanisms. This guideline may
be modified as field & test data accumulates.
2.01 to 3.0 Bad Schedule replacement
deterioration rate is increasing very soon
High loads, overloads, or faults
may fail the connection High
tensions from cold weather or
wind may initiate failure under
normal loading.
Recommendations
Resistance ratio Conditionof fitting Action
> 3.0 Failing Replace As Soon
Normal loads, overloads, or faults As Possible
may fail the connection. High
tensions from cold weather or
wind are likely to initiate failure
under normal loading