Vectoring basics & 1 element power point from eric haut at pgn (portland, or)

1. Vectoring Basics
Start With a Zero
Reference Voltage.
 Wye – ENA
 Delta – EBA

2. Vectoring Basics
 Potential – Open Arrow.
 Current – Closed Arrow.
 Arrowhead Denotes Polarity.
 A & C Currents Enter the Polarity side of a Current Coil.
 The ONLY Current Coil that is ever Reversed is B-Phase.
 B-Phase Current Coil Reverses Whenever you Alter it.
Half Coils and ‘Z’ Coils are considered altered.
 All Meter Elements Have Forward Torque at Unity Power
Factor.
You cannot have a C-Phase without first having A-Phase and
B-Phase.
Forward torque means less than 90 degrees between
the Potential coil and the current coil.

3. Sequence for Vectoring
 Learn and Memorize the Three Basic Service Vector Diagrams.
 Learn and Memorize Meter Footprints.
 The Meter Footprints show the Potential Connections and
Currents being measured. Labeling the connections is helpful.
 Apply the Rules Regarding Forward Torque and Which Current
Coils may be Reversed.
 Draw the Meter Vectors.
 Create a hypothetical load.
 Do the Math.

4. One Element Meters
 Forms 1 & 3 (Conforming)
 Forms 2 & 4 (Non-Conforming)

5. Form 1 and 3
 System Vectors.
 Meter Vectors.

6. Form 1 and 3
 Simple 2-Wire Circuit.
 N=2 , N-1=1 Element.
 Conductor w/o Current Coil
is Common to the Potential
Coil.
An Element is One
Current Coil and One
Potential Coil.

7. Form 2 and 4
 Service / System Vectors.
 Current coils are ½ to
Compensate for Potential
Coil being across 240 Volts
 Meter Vectors.
B-Phase Current is
reversed.
This Creates Forward Torque for
Both Current Coils Interacting
with the Potential Coil.

8. Form 2 and 4
 3-Wire Circuits.
 N=3 , N-1=2.
 # of Coils = 1.
Note-Some may be Tempted to
Consider this a 1 ½ Element
Meter.
Current Coils are Half. Two Half
Coils Makes One Full Current
Coil.

9. Service Vectors and Footprint

10. Label the Meter Connections

11. Drawing the Meter Vectors
 Apply the Rules Regarding
Forward Torque and Which
Current Coils may be
Reversed.
 Draw the Meter Vectors.
Current Coils are ½. This means
B-Phase is reversed. Voltage is
Between A-Phase and B-Phase
with Polarity at A-Phase.

12. Drawing the Meter Vectors
 Apply the Rules Regarding
Forward Torque and Which
Current Coils may be
Reversed.
 Draw the Meter Vectors.
Current Coils are ½. This means
B-Phase is reversed. Voltage is
Between A-Phase and B-Phase
with Polarity at A-Phase.

13. Form 2 and 4
Invent a load:
A-phase has 1200 watts.
B-phase has 1800 watts.
A-B phase has 3600 watts.
1200/120=10 amps
1800/120=15 amps
3600/240=15 amps
6600 watts total
Ia = 10+15 = 25 amps
Ib = 15+15 = 30 amps

14. Form 2 and 4
Remember current coils are
½ and Potential is Eba.
25amps/2 x 240 x cos 0º
+ 30amps/2 x 240 x cos 0º
= 6600 watts

15. 4s vs. 3s (3-Wire 120/240)
 Both are commonly used for
120/240 3-Wire.
 4s has half current coils.
 3s has full current coils.
 A 4s with 400/5 CTs will
have a multiplier = 80.
 A 3s with 400/5 CTs will
have a multiplier = 40.
Discussion…

16. The End