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70072-0188-00TECHNICAL NOTE 12/2007

PowerLogic, ION, ION Enterprise,MeterM@il, WebMeter andModbus are either trademarks orregistered trademarks ofSchneider Electric.

Electrical equipment should beinstalled, operated, serviced, andmaintained only by qualified

personnel. No responsibility isassumed by Schneider Electric forany consequences arising out ofthe use of this material.

© 2007 Schneider Electric. All rights reserved.

www.powerlogic.com

Troubleshooting Meter WiringThis document outlines wiring troubleshooting procedures for ION7300 series, ION7550 / ION7650, ION8600, and ION8800 meters. Troubleshooting your meter’s

wiring before commissioning can save you time and money.

D ANGER

During normal operation of ION devices, hazardous voltages are present which can cause severe injury

or death. Only qualified, properly trained personnel should perform installation, servicing and operation.

NOTE

In this Technical Note, the three phases are referred to as A, B and C. The meter input terminals are

marked 1, 2 and 3 for the voltage and current phase inputs. Positive phase rotation is seen as anti-

clockwise, with positive phase sequence A, B, C.

In This Document

Checking Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Checking PT and CT Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Checking Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Checking Wiring using the Real‐Time Phasor Viewer . . . . . . . . . . . . . . . . . . . . . . . 3

Using CT Shorting Test Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Using PT Secondary Winding Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Types of Wiring Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Diagnosing Wiring Issues using the Phasor Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Appendix A: Manual Power Calculations to Determine Wiring Errors . . . . . . 7WYE Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

DELTA Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

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Checking Wiring Diagrams Troubleshooting Meter Wiring


Checking Wiring Diagrams Study the meter wiring diagrams in your meter’s installation guide to ensure

that the wiring method is correct in your site installation diagrams.

Check all meter wiring to ensure that it is correct and as shown on the site

installation diagrams. Do not rely solely on vector diagrams to determine correct wiring. The wiring should be marked with unique numbers or color coded. This

makes installation and checking easier. If the wiring is incorrect, the meter

displays incorrect readings.

Checking PT and CT Polarity Potential transformer (PT) and current transformer (CT) polarity is normally

indicated by markings at the device terminals. In rare situations, these can be

incorrectly marked. Test to verify that the PT and CT polarities are correct as

marked, especially if protection relays are installed in the secondary circuits of the

PTs

and

CTs.

Incorrect

operation

will

occur

if

the

polarities

are

incorrectly

marked.

CTsPolarity can be tested using the flick test. Connect an analog ammeter (hand‐held

multi‐meter) to the secondary terminals of the CT, meter positive to X1 and

negative to X2. Using a suitable low‐voltage battery, connect the negative terminal to H2 of the CT. While watching the analog ammeter, apply a current pulse to the

CT by connecting and disconnecting the battery positive to H1 of the CT. If the

polarity is correct, the meter needle gives a positive flick on closing and a negative

flick on breaking the circuit.

PTsTest PT polarity in the same way as the CT (connecting the battery to the primary

side) or by applying a low voltage (for example, 120 VAC) to the primary winding

and comparing primary and secondary voltages on a dual trace oscilloscope.

Checking WiringTest all wiring by ringing out and mark the conductors with wire numbers as

indicated on the drawing. The conductors or cabling should be disconnected from

terminals at both ends. Ringing out is best done using an audible continuity tester. Connect the tester between a wire and ground. At the other end, short wires to

ground one by one until the correct conductor is located. Mark the tested

conductor at both ends.

C AUTION

Do not ring out conductors that are energized.

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Troubleshooting Meter Wiring Checking Wiring using the Real-Time Phasor Viewer


Checking Wiring using the Real-Time Phasor ViewerION Setup version 2.1 and higher has a real‐time Phasor Viewer available for some

meters. The Phasor Viewer provides detailed harmonics calculations for a voltage

or current input on a meter. This information is valuable for power quality

analysis, selecting properly rated transformers, and fault detection. For more

details regarding

the

Phasor

Viewer,

refer

to

the

ION Setup User Guide.

NOTE

The Phasor Viewer in ION Setup is configured by default to display correctly for the meter installer. Users

can change the display to rotate clockwise or counterclockwise using the Phasor Rotation option located

on the Conventions tab under ION Setup Tools Options.

To access the Phasor Viewer:

1. Log on to ION Setup and connect to your meter in Basic Mode.

2. In the Setup Assistant, go to the Verification screen and click the Wiring tab.

3. Select Phasor Viewer, then click Confirm.

The Phasor Viewer appears, containing both voltage and current phasors on the

Combined and Side by Side tabs. The combined view also contains power readings.

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Using CT Shorting Test Blocks Troubleshooting Meter Wiring


Using CT Shorting Test BlocksA current transformer (CT) develops a very high voltage across its secondary

winding if the secondary circuit is open circuited while current is flowing in the

primary winding. This could damage the CT and cause electric shock. It is

recommended that you use a CT shorting device in the secondary circuit. If the

metering circuit

needs

future

maintenance,

you

can

safely

short

the

CT

secondary

to perform maintenance without switching off the primary system.

Using PT Secondary Winding FusesThe PT secondary circuit should be fitted with fuses as shown in the meterʹs

technical documentation. A practical choice of fuse rating is 2A. The fuses should

be properly coordinated with any other fuses on the same circuit. When the fuses

are removed, the meter is isolated from the PT and maintenance can be done

safely.

Additional tests could include:

CT magnetization curve

PT phasing check

Ratio check

Check CT polarity back to meter terminals

Inject meter from test terminal

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Troubleshooting Meter Wiring Types of Wiring Issues


Types of Wiring IssuesIf you suspect a wiring problem, first check that the meter is programmed properly

with the correct PT and CT ratios and that the Volts Mode setting is correct.

Depending on the configuration, there can be 3 CT and 3 PT secondary windings

(12 conductor ends) that need to be applied to the meter with the correct polarity. Without proper commissioning testing, these could be connected incorrectly, causing the meter to display false readings. Possible wiring errors can include:

Swapped current phases

Incorrect current polarities

Swapped voltage phases

Incorrect voltage polarities

For most of the above wiring errors, the meter displays correct values for voltage

and current while the W, VA, VAR and power factor values are incorrect (for

example, when

metering

a load,

a negative

kW

value

indicates

incorrect

polarities).

Diagnosing Wiring Issues using the Phasor ToolDownload the phasor tool from the Support area of the powerlogic website. The

phasor tool is a Microsoft Excel spreadsheet. You must enable macros in Microsoft Excel for the phasor tool to work.

Before using the phasor tool, verify the following:

Your meter’s Volts Mode setting (Delta or Wye).

Your meter’s

frequency

matches

the

frequency

of

the

system

you

are

metering.

Your loads are balanced and non‐distorted (THD ~0).

You must enter the per‐phase power parameters as read by your meter, either kW

and PF or voltage and current angles.

If your meter is configured for Wye Volts Mode, note the power parameters for phase A, B and C from the front panel display, through the Vista component of ION Enterprise or from the real‐time data screens in ION Setup.

If your meter is configured for Delta Volts Mode, temporarily switch the meter

to 4‐Wire Wye Volts Mode. Read the per‐phase power parameters for phase A

and phase C from the front panel display, through the Vista component of ION

Enterprise or

in

the

real

‐time

data

screens

in

ION

Setup.

Ignore

phase

B

information. Return the meter to Delta Volts Mode.

Open the phasor tool spreadsheet in Microsoft Excel, enable macros, and

acknowledge the disclaimer. Follow the instructions on the spreadsheet to

generate actual and corrected phasors to determine meter wiring errors. Refer to

the example document that accompanies the phasor tool for examples.

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Diagnosing Wiring Issues using the Phasor Tool Troubleshooting Meter Wiring


Refer to “Appendix A: Manual Power Calculations to Determine Wiring Errors”

on page 7 for more information.

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Troubleshooting Meter Wiring Appendix A: Manual Power Calculations to Determine Wiring Errors


Appendix A: Manual Power Calculations to Determine Wiring Errors

You can confirm correct wiring with the following steps:

1. Determine the load characteristics: You need to know rough estimates of the VA or W rating and power factor. If the plant is not running at full load, this

can have an effect on the power factor. Induction motors have poor power factors when operating at less than full load.

2. Perform Power Calculations: Perform calculations to determine the expected

power parameters for your application, using the voltage, current, and power

values displayed on the meter.

When calculating power parameters, use a simplified model. Visualize the meter’s

input circuits as 3 separate voltmeters with a common connection brought out to

the VREF (V4) terminal. Current inputs operate like 4 separate ammeters.

Using the above model of the meter makes it easier to understand the various

configurations and voltage modes.

NOTE

Some ION meters do not have VREF (V4) or I4 terminals.

V1 V2 V3 A1 A2 A3 A4

V1 V2 V3 VREF I11 I12 I21 I22 I31 I32 I41 I42

Meter

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WYE Mode Troubleshooting Meter Wiring


WYE ModeWhen the meter is set for WYE mode, each of the phases can be seen to be metered

by a separate power meter. Each phase can therefore be checked independently

(see figure below).

Power Calculations:For a balanced and non‐distorted (THD approaches 0%) load, the power parameter totals can be calculated as below:

kW = 3* | Vln | * | I | *power factor

kVA = 3* | Vln | * | I |

kVAR = SQRT(kVA*kVA

‐kW*kW)

Check each of the power parameters on a per phase basis. In WYE mode, the per‐

phase power parameters should be one third of the totals if the load is balanced. If your meter does not display power values per phase, you can do the following:

1. Remove the fuses for V2 and V3, isolating these inputs from the meter. Check

that the meter displays zero readings for VBN and VCN. The meter now uses

the voltage applied to V1 and the current applied to I1 to determine the power

parameters for the A phase. The meter should display kW, kVAR and kVA

readings that are 1/3 of the total values calculated.

2. Perform the same check for B phase by removing the V1 and V3 fuses.

3. Perform the same check for C phase by removing the V1 and V2 fuses.

NOTE

The readings obtained by performing the above check are only accurate if the meter’s system frequency

matches the frequency of the system being monitored.

Table 1 and 2 show how the power parameters (kVA, kW and kVAR) are affected

by incorrect connection of the voltage and current wiring. Only single error

V A0º

VC

120º

VB

240º

IC

100º

IBI A

220º

340º

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Troubleshooting Meter Wiring WYE Mode


situations are shown; there are many more possible multiple‐error combinations. The power values shown are normalized values, based on the correct values. The

tables are shown for a load with lagging power factor of about 86%.

Normalized Power Parameters (Volts Mode = WYE)

Table

1:

Current

connections

correct,

with

voltage

connections

as

shown:

kVA kW kVAR

Va,Vb,Vc n/a n/a n/a

Va,Vc,Vb 0 0 0

Vb,Va,Vc 0 0 0

Vc,Vb,Va 0 0 0

-Va,-Vb,-Vc n/a -1 -1

-Va,Vb,Vc 0.3 0.3 0.3

Va,-Vb,Vc 0.3 0.3 0.3

Va,Vb,-Vc 0.3 0.3 0.3

Vb,Vc,Va n/a 0 -2

Vc,Va,Vb n/a -1 n/a

Table 2: Voltage connections correct, with current connections as shown:

kVA kW kVAR

Ia, Ib, Ic n/a n/a n/a

Ia, Ic, Ib 0 0 0

Ib, Ia, Ic 0 0 0

Ic, Ib, Ia 0 0 0

-Ia, -Ib, -Ic n/a -1 -1

-Ia, Ib, Ic 0.3 0.3 0.3

Ia, -Ib, Ic 0.3 0.3 0.3

Ia, Ib, -Ic 0.3 0.3 0.3

Ib, Ic, Ia n/a -1 n/a

Ic, Ia, Ib n/a 0 -2

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DELTA Mode Troubleshooting Meter Wiring


Example

You have just installed an ION meter. The known good power values for the

installation site and the measured values from the meter are shown below:

The meter values are obviously incorrect, and you suspect incorrect wiring of the

current and/or voltage inputs.

Dividing the meter values by the known values gives you the normalized values

as used in Tables 1 and 2:

normalized kVA = 0.333

normalized kW = 0.334 normalized kVAR = 0.332

Inspecting the tables, you can see that your meter may have either of:

any one current phase connection reversed

any one voltage phase connection reversed

This method reduces the list of possible wiring errors and can be used to confirm

a suspected wiring error.

DELTA ModeIn DELTA mode, the measurement is performed using the two wattmeter method. The meter needs only VAB (applied to V1), VCB (applied to V3), I1 and I3 to

measure the total power. VCA is calculated and IB is measured. Both are displayed

but are not used by the meter for the power calculations in DELTA mode.

If all voltages are approximately the same magnitude, then the polarities of VAB

and VCB are either both correct or both incorrect

Checking the Two Wattmeter ValuesFor troubleshooting purposes only, temporarily change your meter from DELTA

mode to WYE mode. In WYE mode, the two wattmeter values are seen on phases

A and C. Ignore any values on phase B. Once you have determined the two

wattmeter values, reset your meter back to DELTA mode.

If your meter does not display per‐phase power values in WYE mode, you can do

the following:

Power Values

ApparentPower Real Power Reactive Power

Known Values 1035 kVA 896.3 kW 517.5 kVAR

Meter Values 345 kVA 300 kW 172 kVAR

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Troubleshooting Meter Wiring DELTA Mode


Remove the fuse for V3, isolating that input from the meter. The meter now uses

the voltage applied to V1 and the current applied to I1 to determine the power parameters for the phase A (wattmeter #1).

Perform the same check for phase C by removing the fuse for V1. The meter now

uses the voltage applied to V3 and the current applied to I3 to determine the

power parameters for phase C (wattmeter #2).

The power values seen for phases A and C differ depending on the power factor

of the system. The following equations can be used to calculate the power values

for wattmeters #1 and #2:

Wattmeter #1:

kW = VLILcos (30o+phi)

kVA = SQRT(kW2 + kVAR2)

kVAR = VLILsin (30o+phi)

Wattmeter #2:

kW = VLILcos (30o‐phi)

kVA = SQRT(kW2 + kVAR2)

kVAR = VLILsin (30o‐phi)

phi = load power factor angle, or angle associated with load impedance

Examples (assuming a balanced, non-distorted load)

System power factor is unity:

kW values have equal magnitude and sign.

kVAR

values

have

equal

magnitude,

but

phase

A

is

positive

and

phase

C

is

negative.

kVA values are the same for phases A and C.

0º

120º

I A

V AB30º

90º

VCB

IC

240º

IB

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System power factor is 86% lagging:

kW value for phase C is the same as kVA value, the value for phase A is half of that.

kVAR value for phase A is half of the total kVA value, the value for phase C is

zero.


System power factor is 86% leading:

kW value for phase C is small, value for phase A is same as kVA value.

kVAR value for phase C is large, value for phase A is zero.


Table 3 and Table 4 show how the power parameters (kVA, kW and kVAR) are

affected by incorrect connection of the voltage and current wiring. Only single

error situations are shown. There are many more possible multiple‐error

combinations. The power values shown are normalized values, based on the

correct values. The tables are shown for a load with lagging power factor of about 86%. See the corresponding information in the “WYE Mode” section for an

example of how to use the tables; use the equations for wattmeters #1 and #2.

0º

330º

I A

V AB30º

90º

VCB

IC

210º

IB

0ºI A

V AB30º

90º

VCB

IC

270º

IB

150º

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Troubleshooting Meter Wiring DELTA Mode


Normalized Power Parameters (Volts Mode = DELTA)

Table 3: Current connections correct, with voltage connections as shown

kVA tot kW tot kVAR tot

V1, V3 n/a n/a n/a

V3, V1 0 0 0

V1, -V3 0.6 -0.3 n/a

-V1, V3 0.6 0.3 -1

-V1, -V3 n/a -1 -1

Table 4: Voltage connections correct, with current connections as shown

kVA tot kW tot kVAR tot

Ia, Ib, Ic n/a n/a n/aIa, Ic, Ib 0 0 0

Ib, Ia, Ic 0 0 0

Ic, Ib, Ia 0 0 0

-Ia, -Ib, -Ic n/a -1 -1

-Ia, Ib, Ic 0.6 0.3 -1

Ia, -Ib, Ic n/a n/a n/a

Ia, Ib, -Ic 0.6 -0.3 n/a

Ib, Ic, Ia n/a -1 n/a

Ic, Ia, Ib n/a 0 -2

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