Measurement Transformers Clause Samples
The Measurement Transformers clause defines the requirements and standards for devices used to measure electrical quantities such as voltage and current within a system. It typically outlines the specifications for accuracy, installation, maintenance, and calibration of current and voltage transformers that are integral to metering and protection schemes. By establishing clear guidelines for these measurement devices, the clause ensures reliable data collection and system safety, thereby minimizing errors in billing, monitoring, and fault detection.
Measurement Transformers. (A) The terms "current transformer" and "voltage transformer" used in paragraphs 3.3 and 3.4 below do not preclude the use of other measuring techniques with a performance equal to that specified for such Measurement Transformers.
(B) For each circuit, current transformers (“CT”) and voltage transformers (“VT”) must meet the requirements set out in paragraphs 3.3 and 3.4 below.
(C) Where a combined unit measurement transformer (i.e., VT and CT) is used, the Tests for Accuracy described in clause 8 of IEC Standard 44-3 in relation to mutual influence effects must also be met.
(D) All Measurement Transformers must be of a wound construction.
Measurement Transformers. (A) The terms "current transformer" and "voltage transformer" used in paragraphs 3.3 and
Measurement Transformers. For each circuit, current transformers ("CT") and voltage transformers ("VT") shall comply with the requirements set out in Sections 5.1.1 and 5.1.2. Additionally, where a combined measurement transformer (VT & CT) is provided the "Tests for Accuracy" as covered in clause 8 of IEC Standard 44-3 covering mutual influence effects shall be met.
Measurement Transformers. For all installations with new/replaced measurement transformers the Meter Operator shall confirm and record from site tests and inspections:-
22.2.1 the installed unit details including:- serial numbers, rating, accuracy class, ratio(s); Superseded
22.2.2 CT ratio and polarity for selected tap; and
22.2.3 VT ratio and phasing for each winding. For installations with existing measurement transformers the Meter Operator shall wherever practically possible perform Sections 22.2.1, 22.2.2 and 22.2.3 above, but at a minimum must confirm and record VT and CT ratios. If the Meter Operator is not able to confirm the CT ratio on site then the Meter Operator must record the reason why on the commissioning record and liaise with the relevant Distribution (or Transmission) Business to obtain the required information.
Measurement Transformers. For each circuit current transformers (CT) and voltage transformers (VT) shall meet the requirements set out in clauses 5.1.1 and 5.
Measurement Transformers failure/fault characteristics), on-site accuracy tests shall be performed on such Meters at intervals not exceeding 5 years for Meters for the measurement of Active Energy and intervals not exceeding 10 years for Meters for the measurement of Reactive Energy;