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Components and technical solutions for power electronics

CURRENT AND VOLTAGE SENSORS

- Industry Current Sensors - Traction Current Sensors - Traction Voltage Sensors - Traction Voltage Detectors - Common information In the industrial and railway sectors, where the tendency for all players is towards higher performance, ABB current and voltage sensors provide competitive and adapted solutions. To meet your requirements, they draw on all their qualities to give you the advantage.Resulting from a totally electronic technology, they integrate the latest innovations. More compact, they allow for the optimum reduction in equipment dimensions. Made from high technology material, ABB sensors offer exceptional thermal performance, a stronger mechanical robustness and generally excellent resistance to harsh external conditions. These products conform to ecological, security and strict quality standards.

Technologies

Closed loop Hall effect technology

Principle ABB current sensors based on closed loop Hall effect technology are electronic transformers. They allow for the measurement of direct, alternating and impulse currents, with galvanic insulation between the primary and secondary circuits.The primary current IP flowing across the sensor creates a primary magnetic flux.The magnetic circuit channels this magnetic flux. The Hall probe placed in the air gap of the magnetic circuit provides a voltage proportional to this flux. The electronic circuit amplifies this voltage and converts it into a secondary current IS. This secondary current multiplied by the number of turns NS of secondary winding cancels out the primary magnetic flux that created it (contra reaction). The formula NP x IP = NS x IS is true at any time. The current sensor measures instantaneous values

The secondary output current IS is therefore exactly proportional to the primary current at any moment. It is an exact replica of the primary current multiplied by the number of turns NP/NS. This secondary current IS can be passed through a measuring resistance RM. The measuring voltage VM at the terminals of this measuring resistance RM is therefore also exactly proportional to the primary current IP.

Advantages	Applications
The main advantages of this closed loop Hall effect technology are as follows: ●   Galvanic insulation between theprimary and secondary circuits. ● Measurement of all waveforms ispossible: direct current, alternating current, impulse, etc. ● High accuracy over a large frequency range (from direct to more than 100kHz). ● High dynamic performance. ● High overload capacities. ● High reliability.	Industry Variable speed drives, Uninterruptible Power Suppliers (UPS), active harmonic filters, battery chargers, wind generators, robotics, conveyers, lifts, cranes, welding, electrolysis, surface treatment, laminators, telecommunications, marine, military, etc...	Traction Main converters, auxiliary converters(lighting, air conditioning), battery chargers, choppers, sub-stations, mining, etc...

Electronic technology

ABB voltage sensors based on electronic technology only use electronic components. In contrast to closed or open loop Hall effect technology, no magnetic circuits or Hall effect probes are used in the sensor.This allows for the measurement of direct or alternating voltages with electrical insulation between the primary and secondary circuits.The primary voltage to be measured is applied directly to the sensor terminals: HT+ (positive high voltage) and HT- (negative high voltage or earth). This voltage is passed through an insulating amplifier and is then converted to a secondary output current IS. This secondary current IS is electrically insulated from the primary voltage to which it is exactly proportional. The voltage sensor measures instantaneous values.

In the same way as for current sensors, this secondary current IS can be then passed through a measuring resistance RM. The measuring voltage VM at the terminals of this measuring resistance RM is therefore also exactly proportional to the primary voltage UP.The electrical supply to the sensor is also insulated from the primary voltage.

Advantages	Applications
The main advantages of this fully electronic technology are as follows: ●   Electrical insulation between the primary and secondary circuits. ●    Measurement of all waveforms is possible: direct voltage, alternating voltage, impulse, etc... ●   Excellent immunity to electromagnetic fields. ●   Excellent accuracy. ●   High dynamic performance. ●   Excellent reliability.	Traction Main converters, auxiliary converters(lighting, air conditioning), battery chargers, choppers, sub-stations, mining, etc...

GlossaryDescription of the main current and voltage sensor's characteristics

Nominal primary current (I_PN) and nominal primary voltage (U_PN)
This is the maximum current or voltage that the sensor can continuously withstand (i.e. without time limit).The sensor is thermally sized to continuously withstand this value.For alternating currents, this is the r.m.s. value of the sinusoidal current.The value given in the catalogue or in the technical data sheet is a nominal rating value. This figure can be higher if certain conditions (temperature, supply voltage...) are less restricting.

Operating range (I_PN, U_PN) and temperature (°C)
The sensor has been designed for a certain operating temperature. If this temperature is reduced, then it is possible to use the sensor with a higher thermal current or voltage.

Measuring range (I_PMAX and U_PMAX)
This is the maximum current or voltage that the sensor can measure with the Hall effect. In general, mainly for thermal reasons, the sensor cannot continuously measure this value for direct currents and voltages.This measuring range is given for specific operating conditions. This can vary depending mainly on the parameters below (see calculationexamples p.108 and onwards):

- Supply voltage: The measuring range increases with the supply voltage.
- Measuring resistance: The measuring range increases when the measuring resistance is reduced.
Not measurable overload This is the maximum instantaneous current or voltage that the sensor can withstand without being destroyed or damaged.However the sensor is not able to measure this overload value.This value must be limited in amplitude and duration in order to avoid magnetising the magnetic circuit, overheating or straining the electronic components.A sensor can withstand a lower value overload for longer.