Voltage transformers. (A) The primary winding of VTs must be connected to the circuits being measured.
(B) The secondary windings of VTs for Type 1, 2 and 3 Meters must meet the following criteria: Type of Meter Relevant Standard Minimum Class Accuracy No. of sets Usage 1 IEC 61869-3 0.2 2 VTs (or 1 VT with two (2) or more secondary windings) 1 VT secondary winding dedicated to the Main Meter for CfD Settlement Activities purposes only. Check Meter VTs can be used for other purposes provided that such Check VT Meters comply with the accuracy requirements in paragraph 2.2 of these TSRs.
Voltage transformers. Routine tests ▪ Verification of terminal markings. ▪ Power- frequency voltage withstand test on the primary terminals. ▪ Partial discharge measurements. ▪ Power-frequency voltage withstand test on secondary terminals. ▪ Power – frequency voltage withstand test between sections. ▪ Determinations of errors (accuracy test for phase angle and ratio errors). ▪ Measurement of primary and secondary winding resistance. ▪ Pressure test for the enclosure. ▪ Enclosure tightness test at ambient temperature. 16- Type tests
Voltage transformers. Two VTs or one VT with two or more secondary winding sets in accordance with IEC Standard 186 and with a minimum standard of accuracy class 0.2 shall be provided. The VT secondary winding supplying the main Meters shall be dedicated to that purpose. The VT used for secondary winding supplying the check Meter may be used for other purposes provided the overall accuracy requirements in Section 4.2.1 are met and evidence of the value of the additional burden is available for inspection by Scottish Settlements. The additional burden shall not be modified without prior notification to Scottish Settlements, and evidence of the value of the modified additional burden shall be available for inspection by Scottish Settlements. A VT test certificate(s) showing errors at the overall working burden(s) or at burdens which enable the working burden errors to be calculated shall be available for inspection by Scottish Settlements. The total burden on each secondary winding of a VT shall not exceed the rated burden of such secondary winding. Separately fused VT supplies shall be provided for each of the following:-
5.1.2.1 the main Meter;
5.1.2.2 the check Meter; and Superseded
5.1.2.3 any additional burden, and in each case such fuses shall be located as close as practicable to the VT.
Voltage transformers. 3.4.1 The primary winding of VTs must be connected to the circuits being measured.
3.4.2 The secondary windings of VTs for Type 1, 2 and 3 Meters must meet the following criteria: Type of Meter Relevant Standard Minimum Class Accuracy No. of sets Usage 1 IEC 60044-2 0.2 2 VTs (or 1 VT with two (2) or more secondary windings) 1 VT secondary winding dedicated to the Main Meter for CfD Settlement Activities purposes only. Check Meter VTs can be used for other purposes.
Voltage transformers. Rated primary voltage phase to neutral ________ kV Rated secondary voltage phase to neutral ________ kV Rated Secondary output for: - measuring core ________ VA - Protection Core ________ VA Thermal limit burden ________ VA Accuracy Class for: - measuring core (required = 0.2) ________ - Protection core ________ Impulse withstand voltage ____kV peak Power frequency withstand voltage of primary winding ________kV Power frequency withstand voltage of secondary winding ________ kV Seller Interconnection Works Purchaser Interconnection Facilities (Design Data) Purchaser Interconnection Works Interconnection Works Schedule Testing of Interconnection Facilities Schedule 4 Form of Construction Reports; Project Progress Reporting Monthly progress reports shall be prepared consistent with the following general format and delivered to the Purchaser in accordance with the requirements of the Energy Purchase Agreement.
Voltage transformers. ITEM 11KV SWITCHGEAR VT 11KV GENERATOR NGT 220KV SWITCHYARD VT -----------------------------------------------------------------------------------------------------
Voltage transformers. Voltage transformers shall be suitable for the operation of protective gear, voltage regulating equipment instruments and/or metering and shall be of the wound type. Voltage transformers shall be in accordance with IEC 61869-3 latest edition 2011 with a rated voltage factor of 1.2 and Class 0.5 accuracy. Transformers for protective duty shall be of accuracy Class 3P. All voltage transformers shall have an output rating adequate to cater for the burdens connected to them. The primary windings shall be connected via renewable fuses with current limiting features and the secondary windings through fuses and link, labelled to indicate their function and phase colour to the appropriate circuits. For single phase voltage transformers, both ends of each secondary winding shall be brought out to insulated links. For three phase voltage transformers each phase end shall be brought out to fuses and the neutral of the secondary winding shall be brought out to insulated links. The fuses and links shall then be brought out to insultated terminals located in a terminal box. The secondary fuses shall be capable of being removed and replaced. Isolation of the fuses for this purpose shall be carried out with the CT/VT unit disconnected from the system. For single phase units, separate earth links for each secondary winding shall be provided. Each of the neutral leads shall be connected together at a single point and earthed as close as possible to the voltage transformer. Voltage transformer secondary windings shall be earthed at the terminal box through a link which can be removed for insulation testing. Secondary circuits of voltage transformers shall not be paralleled.
Voltage transformers. Type and Routine Tests
(a) Measurement of primary and secondary winding resistances.
(b) Measurement of ratio and phase angle errors.
(c) Insulation resistance.
(d) Applied high voltage.
(e) Induced high voltage.
Voltage transformers. For the 220 kV levels, capacitive transformers shall be provided, according to the application. It must be taken into account that the transformers shall not produce ferro resonance effects associated with the overhead line capacities. Voltage transformers shall have the following main characteristics: Type of insulation Outside Secondary voltage 110/√3 V Characteristic of measurement cores a) Accuracy class b) Power 0,2 % 15 VA Characteristics of protection cores a) Accuracy class b) Power 3P 15VA
Voltage transformers. Where required a VT to IEC Standard 186 and with a minimum standard of accuracy to Class 1 shall be provided for the metering of a circuit. The voltage transformer may be used for other purposes provided the overall accuracy requirements in Section 4.2.1 are met and evidence of the value of the additional burden is available for inspection by Scottish Settlements. The additional burden shall not be modified without prior notification to Scottish Settlements, and evidence of the value of the modified additional burden shall be available for inspection by Scottish Settlements. A VT test certificate(s) showing errors at the overall working burden(s) or at burdens which enable the working burden errors to be calculated shall be available for inspection by Scottish Settlements. The total burden on each secondary winding of a VT shall not exceed the rated burden of such secondary winding. The VT supplies shall be fused as close as practicable to the VT, with a set of isolating links, suitably identified provided locally to the Metering Equipment.
