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Power Factor Control Relay CXPLUS
6-12-14 Steps Common Point or Volt Free

General Features

The CXPLUS incorporates all the technical features PFC engineers worldwide have been asking for over recent years. The target power factor is set by the user and the CXPLUS will select the most suitable capacitor size using the best fit principle. This allows the use of large and small capacitor steps to match the reactive demand. The most important influence on PFC in the last decade has been the ever increasing effect of harmonic voltages and currents resulting from variable speed drives, UPS supplies, switched mode power supplies and rectifiers etc. All of these devices are generating harmonic voltages which will damage and overload PFC capacitors if they are not limited by fitting harmonic detuning reactors to each capacitor. The CXPLUS detects harmonic voltages and alarms can be set to pre-selected threshold levels THDU.

What do we mean by Power Factor Today ?

Many articles have been written on the true meaning of the term 'Power Factor'. No longer is it true to say that the power factor is measured by the time difference between the current and voltage waves crossing the zero point. This is true for the 'fundamental 50 or 60 hz power factor' known as Cosphi. The true power factor is calculated from the values of kW/kVA – otherwise known as the true RMS power factor. The CXPLUS evaluates both power factors and gives display of the two values. Comparison of these two values enables the consumer to see the effect of harmonic voltages and currents on his system. All power capacitors are given a rated value in kvar based on their output at 50 or 60hz. Therefore the CXPLUS uses Cosphi to switch capacitors in and out according to reactive power demand on the system.

Modbus Data Output

Today’s energy management systems often demand output by Modbus to the BMS ( Business management System ) the PLC controller., or the MINISCADA interface. A Modbus data output module can be added to the CXPLUS by fixing on the back of the relay . For more details see
MODBUS BOLT ON BACK

Ambient temperature and Setting Alarms etc.

The ambient air temperature of PFC cubicle has a strong effect on the capacitor lifetime. The CXPLUS is fitted with an over temperature varistor so as to give visual a alarm and if so required to switch off capacitors one by one once this temperature threshold has been reached . This low cost option also allows automatic start up of the ventilation fan in the cubicle. The temperature monitor shows the actual and highest ambient temperature reached.

Menu 504 in the expert menu will allow the consumer to disconnect capacitors if the THDU level rises above the selected setting. The default setting is 5%

The relay has a large selection of alarm settings and the control menu is divided in two sections:

Menu 100 – The general non professional menu. This enables the works engineer to programme the relay for step switch time, CT ratio, target power factor, output of each exit relay AUTO -F ON (permanently on) – F-OFF ( permanently off) – HOLD .

The OPh feature tells the user how many hours the relay has been in service for since the last reset. An alarm can be set once the pre-selected number of hours has elapsed. A very useful feature to remind the user that the equipment is due for a service.

The MANUAL menu allows the switching of capacitor steps by hand – especially important when commissioning for the first time on a lightly loaded installation.

The INFO menu tells the user the kvar output of each step in comparison with its initial value, the number of times each step contactor has operated and whether each step is AUTO – Alarm ( for ventilation fan contact ) - Permanently ON or Permanently OFF.

The Expert Menus 200-600 allow the professional to select threshold values for alarms etc. The functions of all the menus are clearly explained in the CXPLUS operating instructions issued with each relay. The professional user receives instructions in the handbook to show how to enter these professional settings so as to inhibit unauthorised ' meddling ' with the relay settings.

The CXPLUS follows the normal principle of having 90° phase-shift between voltage and current at unity power factor so that the CT is normally on a different phase to the two phases used for measurement and power supply to the relay Um1-Um2. If this connection is not possible or single phase measurement is used , there is a phase offset function ( Menu 206 ) which allows the CT to be corrected to any phase, with various phase angle offsets. If the CT is connected the wrong way round in error this can be rectified on menu 206.

The CXPLUS is powered by switch mode power supply and accepts any voltage in the range 90-550V 50/60Hz. Previous relays needed voltage transformers for each value – these are no longer needed.

VENTILATION CONTROL:

The CXPLUS has up to 14 steps. Any one of these steps can be used as a temperature alarm switch to start up a fan.. Simply set the step exit relay selected for fan control to AL

WIRING DIAGRAM

Power Factor Control Relay CXPlus

Standard Features

Scroll through voltage harmonics 3rd up to 19th

Modbus output if required

Up to 14 steps. Common stock sizes 6 step and 12 step

Volt free version available

No more voltage transformers. The CXPLUS accepts any voltage from 90 – 550V AC

Backlit LCD display

Ambient temperature recording and max temp data logged. Alarm feature can be actuated from measured temperature

Self commissioning using best fit principle

Scroll down Multimeter of all measured values including Voltage and THDU

Rapid Switch facility down to 1 sec. Per step with discharge timer setting to ensure capacitor must discharge before being re-energised

Counter for each closing of contactor

Data Log of kvar output of each step and % comparison with initial kvar value

Ventilation from control from any one of the exit relays


Display

A high contrast LCD backlit display shows all values including steps in or out of circuit. On initial power up the relay will show the following scroll down values:

Phase-phase voltage

Phase-neutral voltage

Phase Amps

3 phase kW (assumes balanced load)

3 phase kvar to reach target PF

3 phase total kvar

3 phase kVA

THDU % - Total Voltage Harmonic Distortion as % of fundamental

3-5-7-9-11-13-15-17-19 voltage harmonics, each value separately as % of fundamental voltage

Cosphi – fundamental power factor

PF – True RMS power factor

APF – Average time RMS power factor since relay commissioned

F – Frequency of supply

T-LO -Ambient cubicle temperature (if temp indicator optional extra selected)

THI – Max Ambient temp recorded(if temp indicator optional extra selected)

0ph – Hours the relay has been in service since last reset .This value can be set to trigger an alarm


MONITORING AND ALARM FUNCTIONS

The CXPLUS allows the following to be monitored and if threshold values are exceeded alarm contacts M will close:

Low or high voltage switch off if supply voltage is outside nominal limit ( default is 10% ). Low voltage can cause chattering contractors and reduced contactor life

Number of operations of each contactor

Over temp switch off

Recognition of defective capacitors

Failure to reach target Power Factor Alarm and loss of power alarm

Number of hours since last service – Alarm can be set to required number of hours

Fan start up if ambient temp values exceeded

PDF logo Download the CXPLUS Instruction Manual

PDF logo Download the CXPLUS Expert's guide

Power Factor Control Relay CXPLUS wiring diagram


Summary of the Menus on the CXPLUS – with Factory Default Settings

MENU 100 – QUICK START MENU

Default


Default


Un

415

Set L-L system volts

PFC

ON

Selects whether steps are on AUTO-HOLD-ON-OFF

Ct

1

Set CT ratio :1

CPI

1

Target Cosphi

Pt

1

Set VT ratio :1

St

10S

Switching Time

Ai

No

Automatic Initialisation?

YES/NO

OUt

AUTO

Selects what each output does.AUTO-PERM. OFF – PERM.ON- VENTILATION FAN START UP

MENUS 200 – 600 – EXPERT MENUS
To get into these menus please call your supplier

200


MEASURING

400


CAPACITOR DATABASE

201

415

Sets system Voltage Level Un(repeat of Un in Menu 100)

401

75secs

Set discharge time to prevent re-energisation on quick switching sequence

202

1

Sets CT ratio:1 (repeat of Menu 100)

402

5 var

(1.max)

Manual entry of kvar values per step

203

1

Set VT ratio:1 (repeat of Menu 100)

403

AUTO ALL steps

Select what each output does

Same as Out setting in 100 menu

204

10.00%

Tolerance % of Voltage Setting

404

0

Step switch counter

205

YES

Select L-L or L-N as measurement voltage

500


ALARMS

206

90°

Select Phase Angle U-I

501

YES

Select if alarm display is cancelled when fault cleared or not

207

NO

Ai ( Automatic Initialisation) start

502

YES

THD Alarm setting on/off

208

NO

Activate Step kvar Recognition

503

5.00%

% setting for THD alarm if on

209

AUTO

Frequency setting for low quality networks

504

NO

Select if steps are switched off if THDU above target level

210

0°C

Temp setting offset

505

60 secs

Select time delay of THDU alarm




506

NO

Freeze exits if no CT current

300


CONTROL

507

YES

Service alarm for max number of step switchings or operating hours

301

60%

% value of kvar for step switching.

508

80000

Set No. of contactor operations for Alarm

302

1

Target PF 1

509

9000

Set No. of operating Hours for Alarm

303

0.95i

Target PF 2

510

NO

Use temp Sensor terminals as digital input

304

NO

Target PF when exporting

511

NO

Select if Digital input is n/c or n/o

305

10S

Switch Time per step

512

NO

Temp. Alarms 513/514 ON/OFF

306

2S

Step switch swap over time

513

30°C

Temp Setting for exit relay nominated as fan control

307

YES

Activation of Step swap over

514

70°C

Emergency switch off of steps one by one if temp exceeds target setting – default = 55ºC

308

NO

Stop Automatic kvar step detection

515

NO

Target Cosphi setting

309

YES

Blocking defective Capacitor Steps

516

YES

Alarm for defective step if no step kvar output after 3 attempts

310

ON

AUTO-OFF-HOLD setting

517

YES

Step power loss alarm

311

1

Sequential switching selection 1:1:1: etc.last in/first out

600


ALARM RESETS

312

0

Reactive kvar offset

601

NO

All alarms back to factory default

313

1

Assymetrical Switching fast in slow out etc.

602

NO

Resets all recorded data of kvar per step+kvar output of each step

314

NO

Switch off steps if cosphi is leading

603

NO

Resets Operating Hours to zero




604

NO

Resets Average PF




605

NO

Resets Highest Ambient Temp




606

NO

Reset all alarms




607

NO

Displays software version




608

NO

Gives password and allows you to change.


Technical Data

Measurement and Supply Voltage

90– 550V z 5VA max. Fused to Max. 6A
VT multiplication factor adjustable 1......350

CurrentMeasurement

15mA ..... 6A single phase. Internal CT with Current Sensor 20 milliohm. CT multiplication factor adjustable 1.......4500

Exit relay Ratings

Max rating at 240v 50/60 hz phase-neutral Contactor coils 6A inrush
Max rating 415v 50/60 hz phase-phase Contactor Coils 2.5A inrush

Temperature measurement

By varistor or thermocouple

Alarm Contact

Volt free relay normally closed (N/C). Max fuse rating 2A., Switch contact 250V 2.5A

Air Ventilation Control

Achieved by designating one of the exit relays as ventilation fan contact

Data Output

MODBUS RS485 convertor can be fitted if the CXPLUS is to be incorporated on a MODBUS RTU daisy chain.

Operating Temperature

-20+70ºC. Storage -40+85, ºC

Humidity

0-95% - Dew droplets not permitted.

Over Voltage Category

II Pollution Degree 3 (DIN VDE 0110 Part 1 / IEC 60664-1)

Standards Complied with

DIN VDE 0110 part 1 IEC 60664-1:1992
VDE 0411 part 1 (DIN EN 61010-1 /IEC 61010-1:2001
VDE 0843 Part 20
DIN EN 61326/IEC 61326: 1997+A1: 1998+ A2:2000

Conformity Listings

CE - UL - cUL

Connections

Screw Terminals plug in connectors to facilitate easy swap overs

Casing

Front Plastic Facia (UL94-VO)., Rear - Metal case.

IP Ratings

Front: IP50 – IP54 if tent over cover fitted
ear: Rear: IP20

Weight

0.60Kg

Dimensions

144 x 144 x 58mm – Cut Out 138 (+0.5) x 138 (+0.5) mm

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