Capacitive voltage instrument transformers 35..1200 kV

Capacitive voltage instrument transformers 35..1200 kV

Measuring capacitive voltage transformers (CVTs) with paper-oil internal insulation of the CVE series are large-scale voltage converters and are designed to transmit a signal of measuring information to devices for measuring, protection, automation, signaling and control of electrical circuits in a network with a voltage of 35 to 1200 kV. They have one primary and up to 6 secondary windings for measurement and protection.

A feature of these transformers is the presence of a capacitive capacitor, which can be used as a capacitor for high-frequency coupling of high-voltage lines. The low inductance combined with an efficient damping circuit ensures safe and reliable damping of ferroresonance at all frequencies and voltages up to the rated voltage factor.

Capacitive voltage transformers (CVTs) are designed for a service life of at least 30 years (and even more with proper operation) without any maintenance. The oil is hermetically sealed from the air by a stainless steel bellows assembly and all external parts are made of corrosion resistant material.

By design, measuring capacitive voltage transformers (CVTs) are of the reference type with the lower windings in a metal case. Each CVTs consists of a coupling capacitor (CC) that acts as a voltage divider and an electromagnetic unit (EMB) that converts medium voltage to standard low voltage. Depending on the voltage of the system, the CS can be single-section or multi-section. The coupling capacitor and the EMB are sealed from each other, thereby achieving high accuracy and reliability.

The outputs of the secondary windings of the voltage transformer are placed in a terminal box located on the housing at the base of the transformer and closed with a sealed cover. A plate with technical data is attached to the cover of the secondary terminals. The working position of transformers in space is vertical.

MAIN SPECIFICATIONS

  • Rated primary voltage from 35 to 1200 kV
  • Rated secondary voltage 100.100/√3, 110.110/√3 ,120.120/√3
  • Number of secondary windings up to 6
  • Winding accuracy class for measurement 0.2; 0.5
  • Winding accuracy class for protection 3P;
  • Voltage factor 1.5 or 1.9
  • Oil expansion with stainless steel bellows
  • External insulation porcelain or polymer
  • Oil level indicator
  • Ambient conditions: temperature from -45° to +55°
  • Compliance with IEC and IEEE standards or equivalent standards

ADVANTAGES OF VOLTAGE INSTRUMENT TRANSFORMERS

  • High quality oil-paper insulation
  • Minimum amount of oil
  • High seismic resistance of the structure
  • Hermetically sealed stainless steel oil expansion compensators, which ensures complete tightness of the transformer.
  • Resistance to the effects of ferroresonance phenomena
  • Consistent accuracy over time
  • Anti-corrosion materials
  • Does not require maintenance for a long period (at least 20 years)
  • High fire and explosion safety

The description contains the characteristics of transformers that are produced in series. By agreement with the customer, it is possible to manufacture non-standard transformers.