Recommendations of the VA Joint Working Group. Report to Measurement Canada for Consideration Final recommendations achieved in consensus with EPAC

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1 Reommendations of the VA Joint Working Group Report to Measurement Canada for Consideration Final reommendations ahieved in onsensus with EPAC June 17, 2008 Bakground In 2005 Measurement Canada developed a disussion paper whih identified onerns and issues relating to the existene of potential inequities in the measurement of the legal unit of measure (LUM) known as volt-ampere (VA). It was identified that there are possile inequities resulting from the fat that there are a numer of different VA alulation methods that potentially yield signifiantly different readings under the same load. In the fall of 2005, the VA Joint Working Group (JWG) was launhed to further review and disuss the issues assoiated with the estalishment of methodologies pertaining to the determination of VA demand and VA-hour energy. The mandate of the JWG was to identify and study the fators whih ontriute to the potential inequity, and to make reommendations whih would minimize or eliminate the inequities found. Standard algorithms will need to e identified for eah of the demand units of measurement: watt, var, and volt-ampere (VA). The respetive algorithms and any assoiated provisions for their use will e inluded within the Eletriity and Gas Inspetion Regulations estalished for this purpose. To put into perspetive the fators whih ontriute to the potential inequities, the following ontext is presented. In a simple diret urrent environment the unit VA is in fat a defined unit of measurement whih is simply the amount of voltage aross a load multiplied y the amount of urrent through the load. In terms of measurement, there is no other definition that would lead to differing values of VA given the same load onditions. The question then is, from the perspetive of trade measurement, what is the definition of VA in an alternating urrent, polyphase environment whih inludes harmoni distortions and reative power, (oth leading and lagging)? This is a omplex question of whih, prior to these reommendations, there was no one answer eause there is no unified definition of VA in that eletriity environment. In addition, eause there are multiple methods of responding to a varying load, (demand response harateristis), this reates even greater disparity among measured values of the legal unit of measurement alled VA demand. This situation would e ompletely unaeptale to regulators, measurement professionals and onsumers in any other field of trade metrology suh as mass or volume. In Canada, a kilogram is a kilogram is a kilogram, regardless of loation, type of ustomer, or who the seller is. Page 1 of 11

2 Summary The VA JWG gathered sustantial data, developed analysis tools, and performed evaluations of all the identified fators whih ontriute to variation of VA demand and energy measurement. The results of that work formed the asis for the draft reommendations whih were presented for puli onsultation in Septemer After ompletion of the onsultation, the JWG reonvened with the goals of reviewing omments reeived, determining if modifiations were warranted, and estalishing a final set of reommendations, inluding implementation plan and next steps. The majority of omments reeived during the onsultation related stritly to aspets of implementation suh as time frames, and grandfathering issues. More speifially onerns were expressed regarding the ost impat of large sale reonfiguration and of retiring meters earlier than expeted. Of the tehnial omments reeived, in virtually all ases they related to the potential impat on urrent praties of measurement eing performed outside a meter. The mandate of the JWG did not pertain speifially to measurement eing performed either inside or outside of a meter. The JWG mandate entered upon defining what exatly is a unit of VA in the legal metrology ontext, similar to defining what exatly is a kilogram, or litre or watt, (all of whih are defined as, or ased on, SI units). In that regard, the VA JWG refers omments relating speifially to measurement methods performed outside of a meter to the LUM JWG as suh omments pertain speifially to their mandate. That said, the VA JWG ontends that its reommendations pertain simply to measurement of VA/VA-h and the methods used in alulating VA, and that the priniples should apply regardless of what method or what devie is performing the measurement. It will e the responsiility of the LUM JWG to determine if there are tehnial or metrologial onsiderations speifi to performing VA alulation outside of a meter whih an impat on the aility of meter owners and users to omply with the measurement priniples reommended in this doument. There were virtually no ojetions to the tehnial or metrologial priniples of the JWG s reommendations. In fat there was generally strong support for many of the reommendations inluding the elimination of thermal and exponential demand, standardizing on vetorial addition and diret alulation of VA through inremental measurement of watts and vars, and eliminating the inlusion of Q-h and distortion power as fators in VA determination. Susequent to onsultation, only one reommendation was modified, and an exemption for a ertain ustomer lass was provided for another. But even oth of those adjustments related to onerns pertaining to urrent praties for measurement outside a meter, and not metrologial onerns with the priniple of the reommendation. This is a good indiator that the JWG did exellent work in fulfilling it s tehnial mandate of developing a standard method of VA measurement (energy and demand) that is fair, aurate, onsistent and equitale for the Canadian eletriity trade marketplae. It was lear to the JWG that there is a divide within the eletriity industry with some organizations strongly supporting standardization and others unwilling to do so ased on reasons suh as: this is the way we do or have always done something, there is a ost to hange, rate strutures are ased on the urrent system of measurement. This aused great diffiulty for the JWG as its mandate was to make reommendations ased on sound metrologial priniples and to standardize, to the extent possile, on a definition of VA for the ontext of legal metrology. It is reognized y the JWG that rate strutures and supporting infrastruture have een estalished around a system of measurement that is inonsistent in it s definition of the units of VA/VA-h and in partiular VA demand. From a purely tehnial/metrologial perspetive, the JWG has diffiulty aepting arguments against standardization whih appear to e analogous to suggesting that the aliration of a sale should e adjusted to reflet a rate rather than that the rates of harge (per unit) should e adjusted to reflet the standard measurement. The only rationale given for suh arguments Page 2 of 11

3 appears to e ased on the diffiulty to adjust estalished rates. In any other field of trade measurement, it is the measurement that is onsistent and the rates whih may vary depending on the loation, type of ustomer, or who the seller is. However, the JWG does aept that a ertain amount of time is required for the market to adjust to utilizing a definition of a legal unit of measurement whih is standard and equitale aross the nation. The JWG relutantly even made exeptions to ertain tehnial reommendations in order to satisfy the implementation onerns of ertain stakeholders. Final Reommendations 1.0 Demand Response 1.1 New thermal demand meters no longer e approved in Canada 1.2 Exponential demand funtion no longer e approved in Canada. 1.3 Demand meters shall use a 15 minute integration period with 3 updates of 5 minutes, (sliding window). (This reommendation was modified from that whih was originally proposed as a result of onsultation omments. While the onsultation omments on this speifi reommendation generally pertained to urrent praties of measurement eing performed outside a meter, the JWG nevertheless deided that modifying the reommendation would ease onerns expressed and would failitate the LUM JWG in adopting this reommendation in regards of measurement performed outside a meter. We suggest that the LUM JWG arefully onsider a definition for load profile whih respets the priniples of this reommendation). Note: From a purely tehnial/metrologial perspetive, the JWG maintains that demand meters should use a 15 minute integration period with 5 updates of 3 minutes. In that regard the JWG reommends that a sliding window onsisting of 5 updates of 3 minutes e onsidered in the future. 1.4 High Intervention Customers - Demand meters shall only use a 15 minute demand interval. 1.5 Low Intervention Customers - Demand meters may use a 15, 30 or 60 minute demand interval (Blok or sliding window). Note: As stated in the Summary, there appeared to e a wide disparity among stakeholders with regards to oth the original proposed demand interval of 15 minutes, and the five su-intervals of 3 minutes. The JWG had diffiulty in dealing with this disparity given our mandate of standardization and equity. The JWG onluded that the tehnial reommendation ould e dependant on ustomer lass (high intervention vs. low intervention). The JWG however felt that it s expertise was in the realm of tehnial metrology and was not qualified nor had a mandate to unilaterally estalish parameters for whih types of onsumers would onstitute low intervention, and whih would onstitute high intervention. Many defining parameters were disussed inluding: 1) load size, 2) onnetivity (transmission system vs. distriution system), or 3) as defined y Provinial regulatory authorities. The JWG onluded that it was the responsiility of the eletriity measurement industry to define low vs. high intervention, and in that regard, deferred that deision to EPAC. EPAC has indiated that a new JWG will e reated omprising of representatives from utility rates departments and/or Provinial energy regulators. This JWG will e mandated with defining the parameters and riteria for ustomer lasses whih would e sujet to the various levels of MC intervention. In addition, the JWG reommends that a standard demand interval length of 15 minutes for all Page 3 of 11

4 ustomers regardless of lass e onsidered in the future. 2.0 VA measurement/alulation methodology 2.1 Demand meters shall alulate VA from soure data on a ontinuous interval asis. The time interval for VA soure data for demand alulation is to e as short as possile, ut shall not exeed one minute. 2.2 Q/Q-hr metering shall not e used in determination of VA/VAh or var/varh. 2.3 Polyphase meters shall alulate total VA/VA-h of a load y the vetorial addition of oinidental inremental values of watts/watt-h and vars/var-h per phase. 2.4 Vars/var-h shall e measured diretly and not alulated. 2.5 Vetor Apparent Power shall e determined ased on Budeanu's Reative Power (IEEE 1459 setion ). Vetor Apparent Power shall e determined exluding Distortion Power. Therefore, for the purpose of legal metrology in Canada, the sinusoidal definition in IEEE 1459 setion shall apply to oth sinusoidal and non-sinusoidal onditions. Note: The JWG would prefer to reommend measurement ased on fundamental frequeny only (exluding harmoni power), however, low-ost metering apale of performing that is not widely availale today. The JWG reommends that measurement ased stritly on fundamental frequeny e onsidered in the future. 2.6 VA/VA-hrs shall e determined ased on ontinuous aumulation of instantaneous or inremental values. This will result in a onsistent methodology of determining VA regardless of the quadrant in whih vars our. This reommendation does not prelude eletriity distriutors from using var/var-h measured values in estalishing the asis for a harge or redit for that partiular LUM. Where vars are measured, the registration shall indiate the quadrant (or diretion) in whih the vars exist. Where an eletriity distriutor wants to estalish a harge or a redit for reative energy, the JWG reommends that it e done on the asis of measured values of reative energy and not ased on measured values of VA demand. Exeption: Where the VA determination is ased on the totalization of measurements from more than one meter, it is not possile to perform totalization diretly ased on ontinuous aumulation of instantaneous or inremental values of VA-h. Nevertheless, the priniples of VA/VAh measurement that the JWG reommends in this doument should e applied to totalized quantities as the purpose of totalization is to measure the LUM of two or more separate meters, and omine those quantities in a manner that is representative of the LUM that would e measured if the loads were measured y a single meter. Where var and watt measurement are used for purposes of totalization, an identifiation shall e made to identify in whih quadrant the var/var-h have ourred. This will require independent registers y quadrant, ie) a register for Q1 vars and a register for Q4 vars. This is effetively an issue speifi to the LUM JWG as totalization is a proess that ours outside an approved meter. It is important for the LUM JWG to onsider this reommendation and estalish implementation parameters and time frames as that JWG sees fit, if different from those of the general priniples proposed y the VA JWG. 3.0 Terminology and Equations: See Annex A Implementation Plan General Priniples Page 4 of 11

5 As stated in the Summary, the VA JWG ontends that our reommendations pertain simply to measurement of VA, and that the priniples should apply regardless of what method or what devie is performing the measurement. In general, the JWG reommends that measurement of VA/VA-h e performed in a manner ompliant with the reommendations estalished herein y January 1, An implementation plan pertaining to the approval and grandfathering of meters is identified elow. The implementation plan for oth new meter approvals and grandfathering of existing meters in servie have een modified from those whih were originally proposed. In effet, the modified implementation plan identifies dates pertaining to new meter approvals whih will align with dates proposed y the LUM JWG. Additionally it will allow for all existing meters in servie to e grandfathered for the duration of their usale life. The JWG reognizes that it may not e possile to implement some of the priniples of these reommendations (where pertaining to measurement outside a meter) within that time frame due to external fators (suh as provinial regulatory proesses or rate restruturing issues) eyond the ontrol of meter owners and users. For those situations the JWG reommends that a meter owner or user e allowed to present a formal request to Measurement Canada for an extension inluding a justifiation for the extension and a revised proposal for date of implementation. New Meter Approvals 1.1 Effetive January 1, Effetive January 1, Effetive January 1, Effetive January 1, Effetive January 1, Demand meters will e assessed for ompliane with auray requirements for oth of these reommendations as MC annot distinguish etween ustomer lasses at the approval stage. 2.1 Effetive January 1, Not appliale - There is no impat on atual meters. This is for all intents and purposes a reommendation that pertains to the determination of VA/VA-hr outside of a traditional meter. It is important for the LUM JWG to onsider this reommendation and estalish implementation parameters and time frames as that JWG sees fit, if different from those of the general priniples proposed y the VA JWG. 2.3 Effetive January 1, Effetive January 1, Effetive January 1, Effetive January 1, Grandfathering of Meters In-servie Page 5 of 11

6 1.1 Effetive January 1, 2012, no new meters of this type will e eligile for verifiation. Meters urrently in servie at that time will e allowed to remain in servie until the end of their urrent and susequent reverifiation periods. 1.2 Effetive January 1, 2012 no new meters of this type will e eligile for verifiation. Meters urrently in servie at that time will e allowed to remain in servie until the end of their urrent and susequent reverifiation periods, (inluding susequent reverifiation periods estalished through seal extension). 1.3, 1.4 and 1.5 Effetive January 1, 2012 new meters whih do not onform to the reommendation will not e eligile for verifiation. Meters urrently in servie at that time will e allowed to remain in servie until the end of their urrent and susequent reverifiation periods, (inluding susequent reverifiation periods estalished through seal extension). Note: For reommendations 1.2 to 1.5: All meters (inluding sample meters that represent a homogeneous lot of meters) whih are returned to a verifiation faility for reverifiation shall e reprogrammed to perform demand measurement in the manner estalished in reommendations 1.3 and 1.4 (or 1.5 as appliale) efore eing reverified and returned to servie. This means that the sample meters will have to e exluded from their lot susequent to inspetion and testing. The installed meters of the lot may remain in servie until the end of their urrent and susequent reverifiation periods, (inluding susequent reverifiation periods estalished through seal extension). 2.1, 2.4 and 2.5 Effetive January 1, 2012 new meters whih do not onform to the reommendation will e not eligile for verifiation. Meters urrently in servie at that time will e allowed to remain in servie until the end of their urrent and susequent reverifiation periods, (inluding susequent reverifiation periods estalished through seal extension). 2.2 Not appliale - There is no impat on atual meters. This is for all intents and purposes a reommendation that pertains to the determination of VA/VA-hr outside of a traditional meter. It is important for the LUM JWG to onsider this reommendation and estalish implementation parameters and time frames as that JWG sees fit, if different from those of the general priniples proposed y the VA JWG. 2.3 Effetive January 1, 2012 new meters whih do not onform to the reommendation will e not eligile for verifiation. Meters urrently in servie at that time will e allowed to remain in servie until the end of their urrent and susequent reverifiation periods, (inluding susequent reverifiation periods estalished through seal extension). The VA JWG strongly reommends that existing 2-element meters whih do not omply with this reommendation e voluntarily withdrawn from servie as soon as pratiale due to the high potential for inequity and inauray whih inreases as load eomes more unalaned. 2.6 Effetive January 1, 2012 new meters whih do not onform to the reommendation will e not eligile for verifiation. Meters urrently in servie at that time will e allowed to remain in servie until the end of their urrent and susequent reverifiation periods, (inluding susequent reverifiation periods estalished through seal extension). It is important for the LUM JWG to onsider this reommendation where pertaining to measurement performed outside a meter and estalish implementation parameters and time frames as that JWG sees fit, if different from those of the general priniples proposed y the VA JWG. Note: For reommendations 2.1, and 2.3 to 2.6: All meters (inluding sample meters that represent a homogeneous lot of meters) whih are returned to a verifiation faility for reverifiation shall e reprogrammed to perform VA determination in the manner estalished in these reommendations efore eing reverified and returned to servie. This means that sample meters will have to e exluded from Page 6 of 11

7 their lot susequent to inspetion and testing. The installed meters of the lot may remain in servie until the end of their urrent and susequent reverifiation periods, (inluding susequent reverifiation periods estalished through seal extension). Key Performane Indiators The VA JWG suggests using the following indiators to measure the rate of progress at whih the perentage of meters in servie omply with these reommendations. These KPI s make use of existing programs and availale proesses for data gathering. 1) Manufaturers to provide sales data. This will provide and indiation of the numer of ompliant meters oming in to servie and an e expressed as a perentage of total population. 2) Use MC Marketplae Monitoring targeted inspetions to determine whih VA / Demand meters (of those inspeted) are ompliant, again providing a ratio. 3) Use MC dispute investigations to determine whih VA / Demand meters (of those inspeted) are ompliant, again providing a ratio. Review Cyle The VA JWG suggests that these reommendations e reviewed in 5 years from date of aeptane y MC. Completed Steps 1) VA draft reommendations developed and puli onsultation performed. 2) VA JWG Report sumitted to EPAC for onsideration. 3) Consolidation of onsultation omments and JWG response prepared and translated. 4) Final report for MC onsideration prepared susequent to puli onsultation as well as disussion and diretion from EPAC. Next Steps 1) Puliation of onsolidated onsultation omments and JWG response. (To e done in onjuntion with puliation of same from LUM JWG). 2) Puliation of reommendations and implementation plan upon aeptane y MC. 3) Identify hanges required to existing MC Speifiations pertaining to meter approval, verifiation/reverifiation, installation, and use. 4) Identify if any new test equipment is required in regards of approval of meters and verifiation of meters. (The JWG disussed this throughout various meetings and it was generally onfirmed that MC ELSD has, or will have, the apaility to assess meters for ompliane with these reommendations). Page 7 of 11

8 5) Effetuate hanges to Speifiations where required and pulish. Conlusions The JWG elieves that it has ahieved the est possile reommendations in regards of its mandate to develop a standard method of VA measurement (energy and demand) that is fair, aurate, onsistent and equitale for the Canadian eletriity trade marketplae. It was reognized early on in the JWG s work that the fators pertaining to VA demand in fat pertain to VA-h energy units as well. It was also reognized that many of the fators pertaining to VA would in fat relate to Watts and Vars as well. This is partiularly evidened in the reommendations onerning demand response harateristis as demand applies to eah of those legal units of measurement. The reommendations pertaining to VA/VA-h measurement/alulation methodology effetively amount to defining what is a unit of VA in the legal metrology ontext (not the sientifi or purely theoretial ontext). Should MC aept these reommendations and move forward with implementation, it would e prudent to reognize that the units Watt/Watt-h and Var/Var-h also e more speifially defined in a similar manner. Final Report prepared y: Mike Araham Chairperson VA JWG Senior Program Offier - Eletriity Measurement Canada VA JWG memers: Adnan Rashid - Measurement Canada Jean Joly - Hydro Quee Suhas Chandra - Itron Jeff Rihardson - Elster Metering (Brent Hughes - BC Hydro) Brent was a ontriuting memer for the duration of the ommittee with the exeption of the final meeting whih resulted in these final reommendations. (Lu Tessier) Lu haired the ommittee during Mike s asene. Page 8 of 11

9 Annex A Terminology The Workgroup estalished a terminology listing to ensure that onsistent terms and interpretations were eing used. It is reommended that Measurement Canada (MC) type approval, verifiation, and installation and use speifiations e amended to inlude the following terminology as appliale: Arithmeti sum of VA: Otained y using a formula to determine the individual VA values in eah phase, and susequently arithmetially adding eah phase value. Blok interval demand meter: Blok interval demand meters averages the power over a speified period of time. The time intervals (usually 15 minutes), follow eah other ontinuously and onseutively (i.e.: when one interval onludes, the next one egins). Budeanu's Reative Power definition: Refer to IEEE 1459, setion Buhholz definition of apparent power: Refer to IEEE 1459, setion Calulation Frequeny: In general frequeny is defined as the measurement of the numer of ourrenes of a repeated event per unit of time. In the ontext of this doument Calulation Frequeny means the frequeny used y the meter to alulate the values that serve to estalish the demand. As an example it ould e alulate every pre-determined period suh one per seond, one per yle, or at every sample that the tehnology of the meter an measure. Demand Interval (of an integrating demand meter or of a pulse reorder): The speified overall interval of time on whih a demand measurement is ased. Usually 15 minutes. Demand meter: An eletriity meter intended to measure demand or maximum demand or oth, where demand is the rate at whih eletrial energy is supplied to a load and whih displays and stores the demand(s). Distortion power: Budeanu's Distortion Power is defined in IEEE 1459 setion Exponential demand: Represents the emulation of the thermal demand measurement in an eletroni meter. Fundamental Ative Power: Refer to IEEE 1459, setion P 1 kt kt 1 Vidt 1 1 Vi 1 1 os Fundamental Apparent Power: Refer to IEEE 1459, setion S1 V1 I1 S P Q Fundamental Reative Power: Refer to IEEE 1459, setion kt Q1 Vidt 11 Vi 11sin kt Page 9 of 11

10 Harmoni: A part of a signal that has a frequeny that is an integer numer multiple of the fundamental frequeny of the signal. The fundamental frequeny is generally the referene frequeny (fref), generally 60 hertz for eletri power. Harmoni Distortion: Refer to IEEE 1459, setion Harmoni Power: The sum of power determined from all like order harmonis of voltage and urrent. IEEE: Institute of Eletrial and Eletronis Engineers JWG: Joint working Group LUM: Legal Unit of Measure Peak splitting: Ahieved y synhronising the eletriity onsumption with the demand interval of a meter to redue the registered value of the peak demand. E.g. Applying a lok load of 100kVA for 15 minutes, eginning at the mid point of the first demand interval and ending at the mid point of the next demand interval, will lead to a registration of two suessive 50kVA peak demand on a lok interval meter. Power Fator: the osine of the phase angle etween voltage V and urrent I. Q meter: An eletriity meter that measures a quantity (referred to as "Q" or "Q hour") that may e otained y effetively lagging the applied voltage to a watt-hour meter y 60º. It is limited to PF range of 60º lag to 30º lead. The quantity "Q hour" was intended to failitate VA measurement in eletromehanial tehnology. Reative power: Refer to IEEE 1459, setion Sliding window demand: Sliding window integrating demand meters follow the same measurement priniple as lok interval however the intervals are not independent of eah other, ut are estalished through a series of su-intervals. Demand is alulated y averaging the load reorded over ontiguous su-intervals whih omine in time to equal the demand interval. Suessive intervals are shifted in time y the length of the su-intervals. Su-interval: A series of equally sized intervals that make up the demand interval used in determining a sliding window demand value (e.g. 5 su-intervals of 3 minutes, in a demand interval of 15 minutes). Thermal demand meter: An eletromehanial meter whih uses the priniples of thermal response to loads in order to provide a demand registration. These devies operate ased on the expansion of metals when heated, and on an eletrial ondutor's heat loss as a result of urrent passing through it. A imetalli oil strip is used to produe preditale defletion of a demand pointer proportional to the power in the iruit. Vetor Apparent Power: Refer to IEEE 1459, setion S P Q v S P P P j Q Q Q P jq v a a Page 10 of 11

11 Equations (numered y reommendation identified in final report) t Blok Demand: BD Energy Wh, Varh, VAh (t= time in minutes) int Blok Demand (15 minute with 3 minute sliding window): BD BD(int) n 5 n1 2.2 Volt-ampere (VA) vetorial VA Watt Var 2.3 Watts (W): W V Ios Polyphase Watts: W V I V I V I p a a os os os Vars (var): Var V I sin Polyphase Vars: Var V I V I V I p a a sin sin sin Volt-ampere (VA) vetorial: VA W Var vetorial Polyphase Volt-ampere (VA) vetorial: VA W Var p vetorial P P 2.4 Vars (var): Var V I sin Polyphase Vars: Var V I V I V I p a a sin sin sin 2.5 Watts (W h ) inluding harmonis: W V I h h h os 23 h1 Vars (Var h ) inluding harmonis: Var V I h h h sin 23 h1 Volt-ampere (VA h ) inluding harmonis: VA W Var h h h Page 11 of 11