Current transformers

Introduction

ETI product series

The ETIMETER series offers a comprehensive range of metering current transformers that provide accurate and reliable current measurements for various applications. They are designed to meet international standards and offer high accuracy, ensuring precise metering and effective protection.

ETIMETER CTR-30 Series - Single-Phase Metering Current Transformers

The CTR-30 series is a range of single-phase metering current transformers suitable for a variety of applications.

Key features of the CTR-30 series:

• Versatile Mounting Options: The CTR-30 series offers both bus bar and DIN rail mounting options, providing flexibility in installation. Mounting sets are included for convenience.
• Connection Terminal with Cover: A connection terminal with a cover is provided, eliminating the need for a fork and ensuring safety and compliance with IP20 protection standards.
• High Accuracy: The CTR-30 series is available in accuracy classes of 0.5 and 1, ensuring precise current measurements for reliable metering and protection.
• Wide Range of Current Ratios: The CTR-30 series offers a wide range of primary/secondary current ratios, catering to different application requirements. Available ratios include 50/5, 100/5, 150/5, 200/5, 250/5, 300/5, 400/5, 500/5, and 600/5.
• Durable Construction: The CTR-30 series features a robust case made of 10% glass-filled polycarbonate, a flame-retardant material classified as UL 94V-0. This construction ensures durability and reliable performance in demanding environments.

Application

Metering current transformers are crucial for various applications:

• Accurate Energy Metering: They provide accurate current measurements to energy meters for billing purposes in industrial, commercial, and utility settings.
• Power System Monitoring: Metering CTs are used in network analyzers to monitor power system parameters, such as current, voltage, power factor, and frequency.
• Protection Relaying: CTs provide current signals to protection relays, which detect faults and isolate faulty sections of the power system to prevent damage and ensure safety.
• Power Factor Correction: Metering CTs are used in automatic power factor correction systems (PFC) to measure current and adjust reactive power compensation to optimize energy efficiency.

Here's how metering current transformers work:

• Primary Winding: The primary winding of the CT consists of a few turns of heavy-gauge wire and is connected in series with the high-current conductor being measured.
• Secondary Winding: The secondary winding has many turns of fine-gauge wire and is connected to the metering instruments or protection relays.
• Magnetic Core: A ferromagnetic core links the primary and secondary windings.

When current flows through the primary winding, it creates a magnetic field in the core. This magnetic field induces a proportional current in the secondary winding. The ratio between the primary and secondary currents is known as the CT's turns ratio. For example, a 100:5 CT will produce a 5-ampere secondary current for every 100 amperes flowing in the primary.