Fluke 435-II, 1760, Hioki PQ3198 and PQ3100 Analyzers

Short answer

The Fluke 435-II, Fluke 1760, Fluke 1770 series and the Hioki PQ3198 and PQ3100 are portable power quality analyzers. They record voltage, current, harmonics, sags, flicker and unbalance. Class A instruments under IEC 61000-4-30 (such as the 435-II and the PQ3198) are used to verify compliance; class S, for diagnosis.

What it is and where it is used

The Fluke 435-II, Fluke 1760, Fluke 1770 series (1773, 1775 and 1777) and the Hioki PQ3198 and PQ3100 power analyzers are portable instruments to measure and record power quality: voltage, current, power, harmonics, interharmonics, sags and swells, flicker and unbalance. They are installed for days or weeks in a panel, on the secondary of instrument transformers or at the point of connection of a plant. Dranetz (HDPQ series) and Metrel equipment serve the same purpose.

The key question when choosing an instrument or reading a report is the class under IEC 61000-4-30: class A defines measurement methods and accuracy so two different instruments give the same result; class S is for studies and diagnosis. For the general concept, see power quality analyzer.

Analyzer class by use of the measurement

Will the measurement be used to verify compliance or settle a difference between parties?
- Yes: Class A analyzer under IEC 61000-4-30
- No: Is it a diagnosis or a qualitative study?
  - Yes: A class S instrument may be enough
  - No: Define the purpose of the recording first

Variants: Fluke 435-II, 1760, 1770 series, Hioki PQ3198 and PQ3100

Model	Application	Main difference
Fluke 435-II	Portable power quality and energy analyzer	Class A under IEC 61000-4-30; adds advanced functions over the 434-II
Fluke 434-II / 437-II	Same 430 Series II family	The 434-II is class S; the 437-II extends the family
Fluke 1760	Three-phase power quality recorder	Fluke presents it for class A verification and event correlation
Fluke 1773 / 1775 / 1777	1770 series of three-phase recording and analysis	Current generation of Fluke recorders
Hioki PQ3198	Power quality analyzer	Certified class A; high-order harmonics
Hioki PQ3100	Power quality analyzer	Class S under IEC 61000-4-30

Main features

Class A versus class S: Hioki describes class A for precise measurements that can be used in disputes and compliance verification, and class S for qualitative studies and diagnosis.
Standardized aggregation: on the 435-II, Fluke indicates the 10/12-cycle aggregation defined by IEC 61000-4-30.
Independent certification: Hioki publishes the certificate of a laboratory that tested the PQ3198 according to IEC 62586-2.
Current sensors: flexible or rigid clamps; their range and error add to those of the instrument.

What class A really requires

IEC 61000-4-30 defines measurement methods and uncertainties for each parameter; it is not a commercial label. Some requirements that distinguish a class A record:

Standardized aggregation intervals. The basic measurement is 10 cycles for 50 Hz or 12 cycles for 60 Hz, aggregated into 150/180-cycle, 10-minute and 2-hour intervals. This allows records from different instruments to be compared point by point.
Time synchronization. Class A requires a time reference with bounded uncertainty (by GPS or NTP); without it, comparing two records at two points of the network is not valid.
Voltage uncertainty. In class A, the uncertainty of rms voltage is ±0.1 % of the declared input voltage; in class S it is larger. This holds only if the measurement chain (instrument transformer, clamps) has adequate accuracy.
Harmonics, interharmonics and flicker are measured with the methods of IEC 61000-4-7 and IEC 61000-4-15 that the standard references.
Event flagging. Sags, swells and interruptions are recorded with their depth and duration, and the value measured during an event is flagged so it does not contaminate the aggregated value of the interval.

IEC 62586-1 defines the requirements of the power quality instrument and IEC 62586-2 the tests to verify them. The certificate from an independent laboratory, like the one Hioki publishes for the PQ3198, supports the manufacturer’s declaration, but does not replace periodic calibration of the instrument. Other class A analyzers with their own guide are the Metrel MI 2892 and MI 2893 and the Janitza MRG Flex and Unipower Unilyzer.

Hioki PQ3198 input data

On the manufacturer’s page and in distributor datasheets, the PQ3198 is listed with voltage up to 600 V rms with a maximum input of 1,000 V AC. It is also listed with a transient range of ±6 kV peak with 2 MS/s sampling, and currents from 500 mA to 5,000 A depending on the sensor (with flexible sensors, currents up to 6,000 A are measured). Hioki declares compliance with IEC 61000-4-30 edition 3, class A. The continuous recording time on the SD card varies with the parameters that are enabled; check the manual for the recording period for your configuration. For the Fluke 1773, distributors list it as class A for nominal voltages between 100 and 690 V, with three-phase and neutral inputs. Transient capture capability differs between models of the 1770 series, so confirm it in the datasheet of the specific model.

How to design a record that is useful

Duration. A useful record lasts at least one full week to include the weekly load cycle; for IEEE 519 or for contracts with utilities, the duration is set by the applicable standard or contract.
Measurement point. Measure at the point of common coupling and, separately, at the suspected load; measuring only at the load hides the effect of the grid.
Instrument transformer ratios. They are noted and configured; a ratio error invalidates the whole record.
Sensors. Flexible clamps have their own range and error; a 5,000 A clamp on a 100 A circuit measures with poor accuracy.
Context logs. Note which equipment was running, because without that context the study cannot correlate events with causes.

Common measurement mistakes

Measuring with the instrument and no reference standard. A record without the applicable limit concludes nothing.
Grounding the wrong reference neutral or reversing clamp polarity: the sign of power ends up wrong and generated energy appears as consumed.
Interpreting a low-amplitude transient as a fault. Instruments with transient capture detect events that do not affect the load; they are interpreted with their duration and energy.
Concluding from a short record. Harmonics and flicker change with production; one afternoon does not represent the plant.

Communications and integration

These instruments are not integrated into the substation SCADA: they store the record in memory and it is downloaded with the manufacturer’s software to produce reports. When the plant needs permanent measurement, a fixed power quality meter is used, such as the Schneider ION 9000, integrated by Modbus or IEC 61850.

Frequent technical questions

Fluke 435-II or Hioki PQ3198 manual: both manufacturers publish manuals and datasheets. The accuracy of a record depends on the clamps and the connection, not only on the instrument.
Fluke 435 and Hioki PQ3198: these are two class A analyzers from different manufacturers; what matters is that the class, sensors and recording period match the objective of the study.
Drive harmonics: the record shows the problem, but the solution comes from the study; see harmonics from variable-frequency drives.
Voltage sags that trip equipment: the analyzer records the sag depth and duration; the sensitivity of the affected equipment is analyzed separately.
Measuring at medium voltage: measure on the secondary of existing instrument transformers; the analyzer is not connected directly to medium voltage.

How we help

Our team performs power quality studies in substations and industry: we define what and where to measure, analyze the record against the applicable standard (for example IEEE 519 for harmonics) and propose the solution. The analysis is done remotely, worldwide, from your records; measurements on site are done in Colombia, or elsewhere on request. See power quality studies and write to us through contact.

References

IEC 61000-4-30, power quality measurement methods; IEC 62586-2, tests of power quality instruments; IEEE 519.
Hioki, PQ3198 product page with input and transient ranges.
Fluke, page and datasheet of the 434-II / 435-II / 437-II family and power quality analyzer catalog (1760, 1770 series).
Hioki, frequently asked questions on IEC 61000-4-30, analyzer comparison (PQ3198, PQ3100) and PQ3198 certificate.

Frequently asked questions

Is the Fluke 435-II class A?

Yes. Fluke presents it as a class A analyzer under IEC 61000-4-30; in the same family, the 434-II is class S. Class A is what is asked for when the measurement is used to verify compliance or settle a difference between parties.

What is the difference between the Hioki PQ3198 and the PQ3100?

Hioki presents the PQ3198 as a class A instrument under IEC 61000-4-30, certified by an independent laboratory, with high-order harmonic measurement. The PQ3100 meets class S, intended for qualitative studies and diagnosis where class A accuracy is not required.

Does a power analyzer replace a power quality study?

No. The analyzer records the data; the study defines where and for how long to measure, compares the results with the applicable standard or contract, and proposes the solution, for example a harmonic filter or a compensation adjustment.