The Measuring Instruments (Active Electrical Energy Meters) Regulations 2006

Definitions

2.  In this Schedule—

“climatic environments” means the conditions in which relevant instruments may be used;

“critical change value” means the value at which the change in the measurement result is considered undesirable;

“disturbance” means an influence quantity having a value within the limits specified in the appropriate requirement but outside the specified rated operating conditions of the relevant instrument. An influence quantity is a disturbance if for that influence quantity the rated operating conditions are not specified;

“f” means the frequency of the voltage supplied to the relevant instrument;

“f_n” means the specified voltage reference frequency;

“I” means the electrical current flowing through the relevant instrument;

“I_max” means the maximum value of I for which the error lies within the MPEs;

“I_min” means the value of I above which the error lies within maximum permissible errors (MPEs) (polyphase relevant instruments with balanced load);

“I_n” means the specified reference current for which the transformer operated relevant instrument has been designed;

“influence quantity” means a quantity that is not the measurand but that affects the result of measurement;

“I_st” means the lowest declared value of I at which the relevant instrument registers active electrical energy at unity power factor (polyphase relevant instruments with balanced load);

“I_tr” means the value of I above which the error lies within the smallest MPE corresponding to the class index of the relevant instrument;

“measurand” means the particular quantity subject to measurement;

“MPE” means the maximum permissible error value as set out in paragraph 15;

“PF” means power factor = cosφ = the cosine of the phase difference φ between I and U;

“rated operating conditions” means the values for the measurand and influence quantities making up the normal working conditions of a relevant instrument;

“U” means the voltage of the electricity supplied to the relevant instrument; and

“U_n” means the specified reference voltage.