Fluke 6100A Electrical Power Quality Calibrator

Fluke 6100A Electrical Power Quality Calibrator

Measurement validation for electrical power applications

The importance of accurate measurement of power and energy has increased dramatically over a relatively short period of time. Deregulation and the increasingly distributed nature of the power supply network mean that measurements are made more frequently, and a higher degree of accuracy is required as previously acceptable levels of error begin to compound.

At the same time, the environment in which these measurements are being made is becoming increasingly hostile to good measurement practice. Harmonic distortion, voltage fluctuations, phase imbalances and other extraneous, re-injected signal components provide an alien environment for measurement devices designed to operate primarily on sinusoidal signals.

Additionally, many new measurement and instrument types have arisen in an attempt to fully characterize network performance, and the nature of the product delivered – electricity. Flicker and harmonic measurements are becoming as commonplace as power factor measurements were a few years ago, and even more complex measurements such as inter-harmonics are now relatively routine.

Against this turbulent change, little progress has been made in the verification of these measurements. Instruments to be used to measure and report precise parameters on power lines carrying significantly distorted, noisy and fluctuating voltages are verified and calibrated under laboratory conditions. Pure, noise free, leveled sinusoidal voltages and currents are still routinely applied as reference signals.

In the field of new measurements and new instrument types, the situation is even worse. Some of the more complex measurements have few standards or protocols which define precisely how they should be made, and there are no real solutions to the problems of how to verify the measurement, or how to calibrate the instrument making it. Perhaps it’s unsurprising that different measurement techniques and different instruments yield different results on what is ostensibly the same measurement, or that measurement traceability often stops at the manufacturer.

Predictably, concern is increasing globally about the acceptability of this situation.

Against this background, Fluke has developed the 6100A Electrical Power Standard.

Comprehensive functionality

Who needs a 6100A?

Validation of electrical power measurements and the equipment that make them is required in many disciplines:

• In design engineering to guarantee that measurements are being made correctly and accurately
• In manufacturing test to make certain that measurements are correct and repeatable on every unit manufactured
• In service and calibration to ensure that instruments continue to perform to specification throughout their lifetime
• In standards laboratories to ensure measurement techniques and equipment meet appropriate standards

The 6100A provides the signals to allow this process to be completed effectively, quickly and easily. More importantly, it ensures that the process of validation is completed thoroughly, accurately and with all measurements being traceable to national standards. The 6100A was designed to produce a comprehensive array of electrical power signal types to a very high degree of accuracy. This can be achieved over 1, 2, 3 or 4 phases independently and simultaneously depending on system configuration.

Phantom power

The 6100A will supply pure sinusoidal voltage to 1000 V and current to 20 Amps. Up to 50 VA’s of power is available from the voltage terminals to support instruments which draw power from the line on which they are measuring. Up to 14 V of compliance is available from the current output to ensure current is delivered in setups involving long cable runs, connectors and switches, or where multiple instruments are connected in series. The current output is also able to produce an auxiliary voltage in order to simulate signals that may be produced by transducers or current probes.

In addition to the values of V, I and phase angle set by the user, the on-screen display shows calculated values of real power (W), apparent power (VA), reactive power (VAR). and power factor (PF). Reactive power for non-sinusoidal signals is calculated by the 6100A using any of seven user selectable methods.

In this mode of operation the 6100A can be used to calibrate or verify measurement of power,VA,VAR, phase angle, power factor, voltage and current on single or multi-phase instruments.

Resolution and accuracy

The Fluke 6100A sets a new benchmark for accuracy in power standards. Voltage and current are generated with up to 6 digits resolution and accuracies approaching 100 ppm (0.01 %). Phase adjustment provides for 1 milli-degree or 10 micro-radian resolution. Phase performance is exceptional, with accuracy to 3 milli-degrees and short term stability to 200 micro-degrees. In multi-phase systems phase accuracy between phases is down to 5 milli-degrees, again with short term stability to 200 micro-degrees. This outstanding level of phase performance equals or exceeds a number of commercially available phase standards.

Flicker

Flicker is a complex measurement which sets out to measure the “annoyance factor” of a flickering light caused by modulation on its supply voltage, which is in turn caused by events such as large loads switching. The measurement is defined by IEC standard IEC61000-3-3. In simple terms, the measurement of flicker is a combination of two variables, amplitude and frequency of modulation over a period of time, (ten minutes to produce the so called Pst or short term flicker severity value). The 6100A simulates flicker by modulating voltage amplitude at a depth and frequency set by the user. The Pst value of this combination is calculated and displayed on screen.

Harmonics

In addition to sinusoidal voltages and currents, the 6100A can supply accurate amounts of harmonic distortion independently on the voltage and current outputs. All of the first 100 harmonics can be set individually by the user, with levels of up to 30 % of the fundamental value. Addition of harmonics does not significantly impair accuracy or compromise traceability of the measurement.

This mode of operation can be used to calibrate or verify measurements made by devices such as harmonic analyzers, power loggers, disturbance analyzers, etc. It is also valuable in ensuring that simpler measurements such as voltage, power or power factor are performed correctly and accurately under non-sinusoidal conditions.

Interharmonics

Interharmonics are continuous signal elements unrelated to the fundamental frequency. For example, in a 60 Hz supply system, 180 Hz is a harmonic (the 3rd) but 190 Hz is an interharmonic.The 6100A can generate two independent interharmonics at a user-definable level and frequency on both the current and voltage outputs.With this function, the 6100A can simulate interharmonics caused by imperfect loads, or deliberately induced signals such as power line carrier signals.

Fluctuating harmonics

Fluctuating harmonics are individual harmonics which are amplitude modulated.The 6100A is able to individually modulate from one to all of the currently defined harmonics at up to 30 % of its nominal amplitude with a frequency of up to 30 Hz, and with a sinusoidal, square or rectangular waveshape.

Dips and swells

Output voltage or current can be caused to dip to a level below nominal or swell to a level above nominal for a period of between half a cycle and one minute. Ramp in and ramp out times, period, repetition delay and dip/swell level are all independently controllable. The dip or swell can be triggered internally to be synchronous with a preset value of phase of the fundamental, or triggered externally from another device.

Complex measurements

Simultaneous application

Full verification of complex measurement devices requires that complex combinations of signals are handled correctly. This fact has been recognized within the power measurement industry, and is being incorporated in IEC 61000-4-30 (Testing and measurement techniques – Power quality measurement methods). This standard requires, amongst other things, that measurement instruments are tested with compound signal types (for example flicker, imbalance and harmonics all present) to ensure that performance is maintained under real world conditions. The 6100A supports this need by making most signal types available simultaneously.

Multi-phase operation

The 6100A Master unit offers self-contained single phase operation, with one voltage and one current output. For multi-phase applications, the addition of one or more 6101A Auxiliary units provides additional phases, with identical performance but without the overhead of controls or display. Additional phases can be added individually until a maximum of four phases is reached. In multiphase systems, each phase remains totally independent and totally electrically isolated, yet synchronized with, and under the control of the master unit. This means applications where phase imbalance or sequence errors are required are simple and easy to arrange.

Specifications:

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