Měřící Energetické Aparáty, a.s.

Měřící Energetické Aparáty, a.s. Measurement of voltage quality in electricity meter  Technicaly possible  Price of realisation?  Interrest of custommers?  Feasibility is time and financialy demanding  Contribution for distribution companies?  Contribution for society?

Měřící Energetické Aparáty, a.s. Measurement of energy quantity and quality  Energy meters are set gauges, measuring functions are stable and consistent  The meter is perceived by society as an unchanging, certified device and even technically well-meaning development can lead to discussion and consequently to distrust  Power Quality Measurement currently goes through a dynamic development  Implementation in the new networks and in already constructed and operated networks  Unification of standards  Time factor: price + performance ↔ time

Měřící Energetické Aparáty, a.s. parameterquantity measurementquality measurement evaluation methodsdeterministicstatistic evaluation periodcontinuous10 periods / 1 week number of values3 × 6 registers91 values measurementV, I, PFV, (in future I) precision requirementscomparable analog circuitsequal comm. requirementscomparable comm. securityrequirednot for now computing power / consumtion normalhigh

Měřící Energetické Aparáty, a.s. Questions for decision about joint measurement of electric energy quantity and quality  Delivery point for measurement of quality of electric energy is point in public distribution network, where energy is exchanged between contracting parties. This point may vary from point of measurement of electric energy quantity  Class A – for contracting relationships  Class S – for statistical evaluation (two tendencies of measuring methods)

Měřící Energetické Aparáty, a.s.  Linearity range of voltage measurement circuits: 1.75 U NOM class S – 3 rd testing state 1.52U NOM, 20% harmonics, 0.723% flicker, 1% interharmonics  Evaluation period: energy quantity / 15min quality / 10min aggregation  Data transfer security: energy quantity / billing quality / informative

Měřící Energetické Aparáty, a.s. Continuous phenomena (flagged 10 minute evaluations)  Frequency evaluation, 10s average value of harmonics basic component  Flicker evaluation, for changes ∆U/U from 1 change/min. upto 4000 ch./min.  Voltage unbalance  Harmonic analysis, frequency of calculation (10 periods/1s, without gaps) Voltage phenomena (U RMS1 or U RMS1/2, hysteresis, clustering algorithms)  For flagging  Secured power supply (measurement uncertainity 1% U nom and 20ms during 1 minute)

Měřící Energetické Aparáty, a.s. Expected development in votage quality measurement  Changes of indicative values ​​for voltage and continuous phenomena  Rapid voltage changes Record of RMS values Oscilographic record Phase angle during inception of rapid change Short change of voltage unbalance Phase shift caused by rapid change  Measurement of harmonics and interharmonics (40. H, 50.H, 100.H)  Transient voltage

Měřící Energetické Aparáty, a.s. Conclusions  Intended association of operational measurements and the measurement of quantity and quality of el. energy is in place  The solution can only be assessed on the basis of operational experience  Verification of measurement in substations which is easily accessible is offering  It is needed to respect different meanings of measurement in substation and on interface between distribution and custommer  Other solutions in case of already constructed and operated networks and another in new networks or in networks with a refurbished power equipment