CTAP-3ph Protection and Metering Current Transformer

Why do we use protection CTs and How are they different from metering CTs?

A protection CT measures large currents, frequently around 65kA. A metering CT will typically measure anything from 100A to 5000A. This means the magnetics required for protection and metering CTs are very different. Notably protection CTs are much heavier than metering CTs because of their increased core materials. Today's needs require another level of sensitivity because protection CTs can attenuate or disguise fast current rise times that need to be monitored.

The CTAP-3ph Three Phase flexible current transformers are the world's first combined metering and protection CT solution and they are flexible current probes with a 0-5A output. The CTAP-3ph allows compatibility with existing 5A metering circuits and 5P10 and 5P20 protection requirement. Unlike conventional CTs, there are no open circuit hazards (High S1-S2 voltages) - ideal for retrospective metering projects and installations in confined spaces where installation of conventional iron core CTs are not possible. The CTAP-3ph 5A output Rogowski Coil current sensing, simplifies installation and eliminates the need for expensive LV/MV plant shutdowns. In addition, the CTAP-3ph modules can be used to convert any voltage output current measuring device to a 1A or 5A secondary.

Typical applications are retrospective energy monitoring, including Data Centres, Hospitals, Banks, Shopping Centres where Energy Management, power, energy and current monitoring is crucial. For all CTAP-3ph three phase current sensor models, a NIST/NPL (UKAS) traceable calibration certificate and certificate of conformance is supplied. All CTAP-3ph sensors use UL94V0 or CSA approved materials. The CTAP-3ph flexible current sensors are suited to permanent or semi permanent installation. The coil sensor is durable, lightweight, flexible and will easily clip-around a power cable - even in confined spaces. The 5A output from the CTAP-3ph current sensor connects direct to installed metering, rotary metering or current transducers.

CTAP-3ph 5A Rogowski Coil facts and important application information

• 0-5A output Rogowski Coil current sensing technology
• Available Rogowski sense coil diameters 100mm, 150mm, 200mm and 330mm
• Isolated measurement outputs connect to kWHr energy metering
• CTAP model with 2.5VA, 5VA or 7.5VA rating
• UL, CSA, AS approved
• Available as 0.25%, 0.5%, and 1% accuracy class
• Allows for long cable runs
• Wide measurement range from 1% to 125% of range
• Ideal for current harmonic measurements
• Operating range -20°C to +65°C
• Safety EN61010-1 1000Vac CATIII, 600Vac CATIV CE marked, UL94V0 flame retardant
• Accreditation certificate and calibration data

• Fast installs are possible in Data Centres, Hospitals, Airports, Shopping Centres and Banks
• Ideal for Current sensing for Active Harmonic Filters where burden can exceed 5VA
• Install without shutting down the LV electrical supply, avoiding expensive down-time costs
• Retrospective energy monitoring include hospitals, shopping centres, server farms, marine/shipping
• Allowing compatibility between Energy Management Systems and legacy energy metering
• Power, energy and current monitoring on solar renewables
• Fast response needed for active harmonic cancellation and filters
• The CTAP-3ph flexible current sensors are suited to permanent or semi permanent installation
• The CTAP current sensor is durable, lightweight and flexible, easily clips around a busbar or feeder
• Suited for installations where conventional CTs are physically too large

Applications

The Powertek CTAP-3ph flexible Rogowski coil sensor and conditioning module are supplied as calibrated sets with a traceable calibrated 0-5Arms output

• Diameters: 100mm/3.85", 160mm/6.2”, 220mm/8.6”, 330mm/11.7" clip-around sensor,
• Split core / wrap-around construction
• Rogowski Coil Sensor Thickness: 8mm/0.31"
• Material: Flexible Thermoplastic rubber, flame retardant UL94V0
• Working voltage: 1000V at 50/60Hz CAT III, tested 7400V 50/60Hz 1 minute

• 1000V UL style 20940, 5mm dia, 3m, 5m and 10m lengths

• Input ranges: From 0-100A to 0-10,000Arms
• Accuracy class options, 10%-125% range: <0.25%, <0.5%, <1.0%
• Casing: Din Rail module UL94V0 and CSA approved polycarb
• Fundamental Frequency: 20Hz to 1500Hz
• Bandwidth: 20Hz-1500Hz CTAP-3ph 5A
• Output ratings: 2.5VA (0.1ohm burden), 5VA (0.2ohm burden) or 7.5VA
• Phase shift: <0.04° at 50/60/400Hz
• Conditioner input impedance: 100kohm
• Accurate with waveform crest factors: 1.4 - 5
• Health monitoring LEDs and fault reporting relay outputs
• Power: 110Vac-240Vac power, optional 24Vdc, 48Vdc and 125Vdc
• Fuse for 230/240Vac instrument power 1A slow blow or time delay
• Includes: Din Rail, PSUs, conditioner and output transformer (5A)

• Operational range -20°C to +65°C

All products have CE, IEC, EN, ASME or BS approvals