Dear Electricity Authority,
Via your organisation's web site https://www.emi.ea.govt.nz/Wholesale/Dat... there are links to seven sub-directories, each containing monthly data files offering half-hourly data on various aspects of electricity generation and consumption in most of New Zealand. Each file contains data for multiple data series, each identified by a sequence of code letters and digits. A straightforward check finds some 2,311 different name sequences across the various files, though some names appear in more than one sub-directory! Many of these names can be deciphered (hopefully correctly, a separate issue), but the problem here is that other name sequences are unintelligible.

My request therefore is for information that would elucidate the correct interpretation so that the data series may be placed into proper relationships with other data series. For instance, given names A1, A2, A3, and A it might be that A = (A1 + A2 + A3), or, the total "A" action is (A + A1 + A2 + A3), or, these are all variants of the single activity at A.
Instead of more hand-waving generalities, here are specifics on some two hundred and seventeen names whose interpretation is dark to me.
First, a collection of names for which every supplied datum is zero:
ATI2201.MRPL.LINE.DEF.X
GLN0332.NZST.PUNZ.NS01.X
KIN0112.POCO.MEEN.POCG011.X
KAW0111.HEDL.TODD.LF109.X
MAT1101.BOPD.CTCT.LF1.X
KOE1101.TOPE.MERX.GEN1.I
KOE1101.TOPE.MERX.GEN1.X
NMA0331.TPCO.MERX.PNL42.I
NMA0331.TPCO.MERX.PNL42.X
TWH0331.WAIK.MERX.555.I
TWH0331.WAIK.MERX.555.X
WIL0331.CKHK.MERX.MILL01.I
WIL0331.CKHK.MERX.MILL01.X
ASB0661.EASH.CNIR.H01.X
HWB1101.OTPO.GN.TPNZ.kWh.I.F
BRK0331.POCO.GN.TPNZ.kWh.I.F
CUL0661.MPOW.GN.TPNZ.kWh.I.F
WGN0331.POCO.GN.TPNZ.kWh.I.F
WPR0331.MPOW.GN.TPNZ.kWh.I.F
ALB0331.VECT.GN.TPNZ.kWh.I.F
HEN0331.VECT.GN.TPNZ.kWh.I.F
HEP0331.VECT.GN.TPNZ.kWh.I.F
SVL0331.VECT.GN.TPNZ.kWh.I.F
MPE1101.NPOW.GN.TPNZ.kWh.I.F
ARI1102.POCO.GN.TPNZ.kWh.I.F
NWD0661.ORON.GN.TPNZ.kWh.I.F
SDN0331.DUNE.GN.TPNZ.kWh.I.F
BRB0331.MERI.GG.MERI.kWh.I.F
MTO0331.NPOW.GN.TPNZ.kWh.I.F
Second, those whose maximum value is greater than zero but less than one:
ATI2201.MRPL.PLUS.DEF.X
ATI2201.MRPL.EDGE.DEF.X
ATI2201.MRPL.RAWE.DEF.X
MAT1101.BOPD.DEEP.DEF.X
ATI2201.MRPL.AGCL.DEF.X
MAT1101.BOPD.AGCL.DEF.X
MAT1101.BOPD.PION.DEF.X
MAT1101.BOPD.BCPL.DEF.X
MAT1101.BOPD.EDGE.DEF.X
WKM2201.TUAR.GBUG.DEF.X
ATI2201.MRPL.PRME.DEF.X
MAT1101.BOPD.PLUS.DEF.X
WKM2201.TUAR.EDGE.DEF.X
ATI2201.MRPL.YESP.DEF.X
ATI2201.MRPL.PRMH.DEF.X
WKM2201.TUAR.PRME.DEF.X
BPE0331.POCO.CTCT.POCG013.X
ATI2201.MRPL.EMHT.DEF.X
KAW0111.HEDL.PUNZ.LF3.I
KAW0111.HEDL.ELKI.LF3.I
ATI2201.MRPL.PPPP.DEF.X
Third, whose maximum value is one or more, but less than ten:
KAW0111.HEDL.MEEN.LF3.I
CUL0331.MPOW.GN.TPNZ.kWh.I.F
KAW0111.HEDL.PSNZ.LF3.I
ATI2201.MRPL.ECOS.DEF.X
KAW0111.HEDL.TODD.LF3.I
KAW0111.HEDL.TRUS.LF3.I
WKM2201.TUAR.EMHT.DEF.X
WKM2201.TUAR.ECOS.DEF.X
ATI2201.MRPL.SUPE.DEF.X
WKM2201.TUAR.OPHL.DEF.X
MAT1101.BOPD.TAOM.DEF.X
KAW0111.HEDL.ECOT.LF3.I
ATI2201.MRPL.OPHL.DEF.X
MAT1101.BOPD.SUPE.DEF.X
KAW0111.HEDL.MERI.LF3.I
PEN1101.VECT.GN.TPNZ.kWh.I.F
WKM2201.TUAR.SELS.DEF.X
MAT1101.BOPD.PPPP.DEF.X
MAT1101.BOPD.PRME.DEF.X
WKM2201.TUAR.SUPE.DEF.X
EDN0331.TPCO.GN.TPNZ.kWh.I.F
KAW0111.HEDL.GENE.LF3.I
ATI2201.MRPL.CLUB.DEF.X
WKM2201.TUAR.HNET.DEF.X
ATI2201.MRPL.HNET.DEF.X
MAT1101.BOPD.SIMP.DEF.X
ATI2201.MRPL.RERL.DEF.X
WKM2201.TUAR.YESP.DEF.X
ATI2201.MRPL.EDNZ.DEF.X
MAT1101.BOPD.OPHL.DEF.X
MAT1101.BOPD.HNET.DEF.X
MAT1101.BOPD.CLUB.DEF.X
ATI2201.MRPL.WISE.DEF.X
MAT1101.BOPD.PRMH.DEF.X
Fourth, whose maximum value is ten or more but less than a hundred:
MAT1101.BOPD.LODE.DEF.X
MAT1101.BOPD.SELS.DEF.X
WRK0331.HAWK.MEEN.R3M.I
BAL0331.OTPO.GN.TPNZ.kWh.I.F
MAT1101.BOPD.FOGY.DEF.X
KAW0111.HEDL.ECOT.LF3.X
WKM2201.TUAR.SIMP.DEF.X
WKM2201.TUAR.FLCK.DEF.X
MAT1101.BOPD.FLCK.DEF.X
ATI2201.MRPL.GBUG.DEF.X
HOR0661.ORON.GN.TPNZ.kWh.I.F
WKM2201.TUAR.FOGY.DEF.X
WRK0331.HAWK.GENE.R3M.X
MTO0331.NPOW.NPGL.G4.I
KAW0111.HEDL.SWCH.LF3.X
ATI2201.MRPL.FOGY.DEF.X
ATI2201.MRPL.FLCK.DEF.X
KAW0111.HEDL.PSNZ.LF3.X
WRK0331.HAWK.GENH.R3M.I
WRK0331.HAWK.MERI.R3M.I
WKM2201.TUAR.IDPL.DEF.X
ATI2201.MRPL.SELS.DEF.X
ATI2201.MRPL.SIMP.DEF.X
WRK0331.HAWK.CTCT.R3M.I
MAT1101.BOPD.GBUG.DEF.X
OAM0331.WATA.GN.TPNZ.kWh.I.F
KAW0111.HEDL.ELKI.LF3.X
MAT1101.BOPD.TASP.DEF.X
RDF0331.HAWK.TRUS.H3H.X
ATI2201.MRPL.IDPL.DEF.X
KAW0111.HEDL.GEOL.LF3.X
WKM2201.TUAR.ECOT.DEF.X
KAW0111.HEDL.GBUG.LF3.X
WKM2201.TUAR.ELKI.DEF.X
WKM2201.TUAR.SWCH.DEF.X
ATI2201.MRPL.GENH.DEF.X
SBK0661.MPOW.GN.TPNZ.kWh.I.F
WRK0331.HAWK.TODD.R3M.X
WKM2201.TUAR.RERL.DEF.X
WKM2201.TUAR.PSNZ.DEF.X
KAW0111.HEDL.MERI.LF3.X
ATI2201.MRPL.SWCH.DEF.X
ATI2201.MRPL.BOPE.DEF.X
ATI2201.MRPL.ECOT.DEF.X
MAT1101.BOPD.ECOT.DEF.X
MAT1101.BOPD.SWCH.DEF.X
Fifth, whose maximum value is a hundred or more but less than a thousand:
ATI2201.MRPL.PSNZ.DEF.X
KAW0111.HEDL.GENH.LF3.X
MAT1101.BOPD.GEOL.DEF.X
ATI2201.MRPL.EKCI.DEF.X
WKM2201.TUAR.GENH.DEF.X
TMU0111.WAIP.GN.TPNZ.kWh.I.F
WKM2201.TUAR.EZYN.DEF.X
WKM2201.TUAR.PION.DEF.X
ATI2201.MRPL.ELKI.DEF.X
SVL0331.UNET.TRUS.RDVL.X
BRY0661.ORON.GN.TPNZ.kWh.I.F
WKM2201.TUAR.EKCI.DEF.X
ATI2201.MRPL.PION.DEF.X
WKM2201.TUAR.PUNZ.DEF.X
WRK0331.HAWK.SIMP.R3M.X
MAT1101.BOPD.ELKI.DEF.X
SVL0331.UNET.CNIR.RDVL.X
ATI2201.MRPL.PUNZ.DEF.X
WRK0331.HAWK.MEEN.R3M.X
MAT1101.BOPD.PSNZ.DEF.X
KAW0111.HEDL.CTCT.LF3.X
ATI2201.MRPL.EZYN.DEF.X
WKM2201.TUAR.CTCS.DEF.X
ATI2201.MRPL.CTCS.DEF.X
KAW0111.HEDL.PUNZ.LF3.X
MAT1101.BOPD.CTCS.DEF.X
HWB0331.OTPO.GN.TPNZ.kWh.I.F
BRB0331.MERI.GG.MERI.kWh.X.F
WTK0111.WATA.GN.TPNZ.kWh.I.F
WRK0331.HAWK.MERI.R3M.X
WRK0331.HAWK.GENH.R3M.X
KAW0111.HEDL.EZYN.LF3.X
ATI2201.MRPL.GEOL.DEF.X
KAW0111.HEDL.GENE.LF3.X
WKM2201.TUAR.CNIR.DEF.X
MAT1101.BOPD.MERI.DEF.X
WRK0331.HAWK.TRUS.R3H.I
ATI2201.MRPL.CNIR.DEF.X
WPW0331.CHBP.GN.TPNZ.kWh.I.F
KAW0111.HEDL.MEEN.LF3.X
WKM2201.TUAR.GENE.DEF.X
KAW0111.HEDL.TRUS.LF3.X
TUI1101.EAST.GN.TPNZ.kWh.I.F
MAT1101.BOPD.CTCT.DEF.X
ISL0661.ORON.GN.TPNZ.kWh.I.F
MAT1101.BOPD.GENE.DEF.X
MAT1101.BOPD.PUNZ.DEF.X
WPG0331.TRPG.CNIR.DEF.X
RDF0331.HAWK.CTCT.H3H.X
MAT1101.BOPD.MERX.DEF.X
WPR0661.MPOW.GN.TPNZ.kWh.I.F
WPG0331.TRPG.TRUS.DEF.X
ATI2201.MRPL.TODD.DEF.X
Sixth, whose maximum value is more than a thousand
ATI2201.MRPL.GENE.DEF.X
MAT1101.BOPD.MEEN.DEF.X
KAW0111.HEDL.TODD.LF3.X
WKM2201.TUAR.MEEN.DEF.X
WKM2201.TUAR.GEOL.DEF.X
ATI2201.MRPL.NZSP.DEF.X
ATI2201.MRPL.MEEN.DEF.X
WRK0331.HAWK.CTCT.R3M.X
MAT1101.BOPD.CNIR.DEF.X
NPK0331.LINE.GN.TPNZ.kWh.I.F
SFD0331.POCO.GN.TPNZ.kWh.I.F
WKM2201.TUAR.NZSP.DEF.X
WKM2201.TUAR.TODD.DEF.X
WRK0331.HAWK.TRUS.R3N.I
MTO0331.NPOW.NPGL.G4.X
WKM2201.TUAR.CTCT.DEF.X
ATI2201.MRPL.CTCT.DEF.X
RDF0331.HAWK.TRUS.H3H.I
ATI2201.MRPL.MERX.DEF.X
WKM2201.TUAR.MERI.DEF.X
WKM2201.TUAR.MERX.DEF.X
WKM2201.TUAR.TRUS.DEF.X
EDG0331.HEDL.GN.TPNZ.kWh.I.F
ATI2201.MRPL.MERI.DEF.X
ATI2201.MRPL.KING.DEF.X
WKM2201.TUAR.KING.DEF.X
MAT1101.BOPD.GENH.DEF.X
MAT1101.BOPD.TODD.DEF.X
ATI2201.MRPL.TRUS.DEF.X
MAT1101.BOPD.TRUS.DEF.X
MAT1101.BOPD.BOPE.DEF.X
HLY0331.WAIK.GN.TPNZ.kWh.I.F
MAT1101.BOPD.EZYN.DEF.X
The greatest value in this group is 6102·527 (for the last), but the corresponding average is just 118·451. None of these series have negative values.

Most of these name sequences do not identify the unit of measurement; those that do state KWH (in a half-hour) as in the penultimate example. Could it be that units are instead Megawatt-hours? This would cause small numbers to appear, though this would have no effect on the all-zero values. But if not, many of the values are being specified to a fraction of a watt-hour (as for the last example), something surely out-of-place in statistics on the national network where a kilowatt is a small thing. Given that this data collection is given the heading "Metered-Data", one wonders just what meters where are measuring this sort of value, and what it means.
Many name sequences include the text DEF - one could guess a meaning for this, but it would be better to have definite information in place of guesswork, and for the other name parts too.
Since this is all information that you publish, I hope that you also have information on the meaning that you can provide.

Yours faithfully,
Nicky McLean