SCOPE : i) This specification covers the design, manufacture, assembly, testing at the manufacturer's works, supply, delivery at site of potential transformers in three phase system of 220 KV, 132 KV and 33 KV class. PT load is also called the burden and is usually defined in volt-amperes and power factor at 120 secondary volts.
Standard IEC accuracy classes are 0.1, 0.2, 0.5, 1. Accuracy of Voltage Transformers As per IEC 61869 "Instrument transformers - Inductive voltage transformers" Ratio errors and phase displacement of metering classes Accuracy class in a voltage transformer is defined as the one if the voltage is guaranteed between 80% and 120% of the primary rated potential difference and for any type of load between 25% and 100% of the accurate rated power with a power factor having an inductive value of 0.8.
For a transformer in no load the following is valid: 1 2 1 2 This equation gives voltage transformation in proportion to the primary and secondary turns. Tables 1 and 2, the PT’s accuracy is not guaranteed.
Current Transformer Accuracy Ratings S.E. The voltage transformer (potential transformer) is designed to closely follow the formula V p / N p = V s / N s for a specified range of operation. A PTs accuracy is dependant on the number of devices connected to the secondary terminals. IEEE C57.13-2016, Table 8: Standard accuracy class for metering service and corresponding limits of transformer correction factors* Accuracy class Voltage Transformers Current Transformers 90% to 100% rated voltage 100% rated current+ 10% rated current 5% rated current Min Max Min Max Min Max Min Max 0.15S - - 0.9985 1.0015 - - 0.9985 1.0015 120 Volt Secondary Models - Double Bushing Catalog Number Primary Voltage Secondary Voltage Turn Ratio Accuracy Class at 100% Accuracy Class at 58% Thermal Rating 60Hz at 30°C Amb. PT load is also called the burden and is usually defined in volt-amperes and power factor at 120 secondary volts. • Three metering accuracy classes are defined for instrument transformers; 0.3, 0.6 and 1.2.
Instrument transformerscomprise a large category of current and potential transformers for various voltage, frequency and physical size ranges.We have broken them up into several different groupings: low voltage, which are system voltages under 15kV; high frequency, operating frequency over 1kHz; and size ranges from board mount parts up to current transformers with window sizes of 254mm by 610mm. WBSETCL / TECH SPEC / Rev.-1 Page 2 of 9 Potential Transformer TECHNICAL SPECIFICATION FOR POTENTIAL TRANSFORMERS 1. A voltage transformer is ideally a transformer under no-load conditions where the load current is zero and the voltage drop is only caused by the magnetizing current and is thus negligible. Potential Transformers are used for both Protection and Metering purposes. Table 1 - Standard Burdens for Potential Transformers Burden Volt-Amps at 120V Burden Power Factor W 12.5 0.7 X 25.0 0.7 Y 75.0 0.85 Z 200.0 0.85 ZZ 400.0 0.85 Table 2 - Accuracy Classes for Potential Transformers Accuracy Class Limits of Transformer Ratio Correction Factor Accuracy Class: 0.5, 0.2, 0.1 CLASS FOR GRID METERING. The equivalent circuit of an actual voltage transformer is shown in Fig-B. WBSETCL / TECH SPEC / Rev.-1 Page 2 of 9 Potential Transformer TECHNICAL SPECIFICATION FOR POTENTIAL TRANSFORMERS 1.
SCOPE : i) This specification covers the design, manufacture, assembly, testing at the manufacturer's works, supply, delivery at site of potential transformers in three phase system of 220 KV, 132 KV and 33 KV class.
Insulation Class … A PTs accuracy is dependant on the number of devices connected to the secondary terminals.
Potential Transformer (PT) Definition – The potential transformer may be defined as an instrument transformer used for the transformation of voltage from a higher value to the lower value.
Model# PTG5 Medium Voltage Potential Transformer; 1; 2 → Model Specification Details.
Model# PTG5 Medium Voltage Potential Transformer; 1; 2 → Model Specification Details. Tables 1 and 2, the PT’s accuracy is not guaranteed. Power: 15VA.
PT mainly introduce two types of errors that affect the accuracy … Thermal Rating 60Hz at 55°C Amb. The accuracy class is guaranteed if the voltage is between 80 and 120% of the rated primary voltage and for any load between 25 and 100% of the rated accuracy power with an inductive power factor of 0.8. Secondary Voltage: 110. Accuracy class in a voltage transformer is defined as the one if the voltage is guaranteed between 80% and 120% of the primary rated potential difference and for any type of load between 25% and 100% of the accurate rated power with a power factor having an inductive value of 0.8. Standard burden designations are shown in Table 1. Table 1 - Standard Burdens for Potential Transformers Burden Volt-Amps at 120V Burden Power Factor W 12.5 0.7 X 25.0 0.7 Y 75.0 0.85 Z 200.0 0.85 ZZ 400.0 0.85 Table 2 - Accuracy Classes for Potential Transformers Accuracy Class Limits of Transformer Ratio Correction Factor R p and L p are primary side resistance and leakage reactance of transformer. Typical ANSI Potential Transformer accuracy classes are 0.3, 0.6 and 1.2. Three Phase 3-Wire Potential Transformer; Model# PTG5 .