IEEE 1159:2009 pdf free download – IEEE Recommended Practice for Monitoring Electric Power Quality
1.1 Scope
This recommended practice encompasses the monitoring of electrical characteristics of single-phase andpolyphase ac power systems. It includes consistent descriptions of conducted electromagnetic phenomenaoccurring on power systems. This recommended practice presents definitions of nominal conditions anddeviations from these nominal conditions that may originate within the source of supply or load equipmentor may originate from interactions between the source and the load.Also,this recommended practicediscusses measurement techniques, application techniques, and the interpretation of monitoring results.
1.2 Purpose
The use of equipment that causes and is susceptible to various electromagnetic phenomena has heightenedthe interest in power quality.An increase in operational problems has led to a variety of attempts todescribe the phenomena. Because different segments of the technical community have used differentterminologies to describe these electromagnetic events, this recommended practice provides users with aconsistent set of terms and definitions for describing these events.An understanding of how power qualityevents impact the power system and end-use equipment is required in order to make monitoring useful.Proper measuring techniques are required to safely obtain useful, accurate data.Appropriate location ofmonitors，systematic studies，and interpretation of results will enhance the value of power qualitymonitoring.The purpose of this recommended practice is to assist users as well as equipment and softwaremanufacturers and vendors by describing techniques for defining, measuring, quantifying, and interpretingelectromagnetic disturbances on the power system.
2. Normative references
The following referenced documents are indispensable for the application of this recommended practice(i.e., they must be understood and used;therefore，each referenced document is cited in text and itsrelationship to this recommended practice is explained). For dated references, only the edition cited applies.For undated references，the latest edition of the referenced document (including any amendments orcorrigenda) applies.
No normative references apply to this recommended practice.
3. Definitions
For the purposes of this recommended practice，the following terms and definitions apply. TheAuthoritaive Dictionary of IEEE Standards Terms [B18]’ should be referenced for terms not defined inthis clause.
3.1 flicker: Impression of unsteadiness of visual sensation induced by a light stimulus whose luminance orspectral distribution fluctuates with time.
3.2 fundamental (component): The component of an order 1 (e.g., 50 Hz, 60 Hz) of the Fourier series of aperiodic quantity.
3.3 imbalance (voltage or current): The ratio of the negative sequence component to the positivesequence component, usually expressed as a percentage.Syn: unbalance (voltage or current)
3.4 impulsive transient: A sudden nonpower frequency change in the steady-state condition of voltage orcurrent that is unidirectional in polarity (primarily either positive or negative).
3.5 instantaneous: When used to quantify the duration of a short-duration root-mean-square (rms)variation as a modifier, refers to a time range from 0.5 cycles to 30 cycles of the power frequency.
3.6 interharmonic (component): A frequency component of a periodic quantity that is not an integermultiple of the frequency at which the supply system is operating (e.g., 50 Hz,60 Hz).
3.7 long-duration root-mean-square (rms) variation: A variation of the rms value of the voltage orcurrent from the nominal for a time greater than 1 min. The term is usually further described using amodifier indicating the magnitude of a voltage variation (e.g.，undervoltage，overvoltage，voltageinterruption).
3.8 momentary interruption: A type of short-duration root-mean-square (rms) voltage variation where thecomplete loss of voltage (<0.1 pu) on one or more phase conductors is for a time period between 0.5 cyclesand 3 s.
3.9 root-mean-square (rms) variation: A term often used to express a variation in the rms value of avoltage or current measurement from the nominal. See: sag. swell, momentary interruption, temporaryinterruption, sustained interruption, undervoltage, overvoltage.