21.August
Overview of KOLA 06J2 Current Transformers. Reliable and Functional Solutions for Power Network Protection
The KOLA series current transformers provide an effective solution for measuring residual currents in three-phase power networks. Thanks to their unique design, these transformers are ideally suited for use with earth fault relays, making them an essential component in enhancing the safety of electrical installations.
Main parameters
| Parameter name | Units | Parameters |
| Nominal voltage | kV | 0.72 |
| Isolation test voltage 50 Hz, 1 min | kV | 3 (1EC 60044-1) |
| Nominal frequency | Hz | 50 |
| Nominal primary current | A | 50; 100; 200; 300; 2000 |
| Nominal secondary current | A | 1; 2; 5 |
| Accuracy class | 10Р10; 0.2 | |
| Nominal thermal current | A | 60; 120; 240; 360; 2400 |
| Short-time current (1 s) | kA | 3; 6; 12; 18; 120 |
| Maximum withstand current | kA | 7,5; 15; 30; 45; 300 |
| Secondary terminals | for 6 mm2 cable | |
| Operating temperature | °C | -5 — +40 |
Key advantages of KOLA current transformers
Variety of sizes: Up to 497 x 300 mm.
Split core versions for easy installation.
Ease of installation: Fixable via fixing points in the housing.
Compact dimensions: Height 90 mm.
Reliable connections: Two secondary terminals ensure efficient communication with external systems.
KOLA transformers are designed to measure the sum of three-phase currents in cable systems. Under normal conditions, this sum is zero, but in the event of an earth fault, it corresponds to the residual current that is transferred to the secondary winding. These transformers are commonly used with static relays for earth fault protection, providing reliable monitoring and control of power networks.
Design and Materials
KOLA transformers feature a toroidal core that can be split open, allowing for installation without disconnecting the cable. The two halves of the core are secured with four bolts, ensuring accurate alignment and stable operation. The secondary winding is encapsulated in high-quality resin, offering excellent electrical and mechanical properties.
Installation Process
The installation of KOLA transformers is tailored to the specifics of the site. Ring-type transformers easily integrate into cable systems, while rectangular models can be installed in a variety of electrical cabinets. During installation, it is important to avoid interference from currents in cable sheaths and to ensure proper grounding.
Selecting the Right KOLA Transformer
When choosing a transformer for earth fault relays, consider the window size and core design. The number of turns in the secondary winding should be selected based on the relay’s requirements and the expected magnitude of the earth fault current.
The correct operation of the earth fault protection relay can be easily verified using a test winding on the transformer, allowing for testing at currents up to 6 A.
Warranty Conditions
The manufacturer provides a warranty of 24 months from the date of commissioning, but no more than 36 months from the date of purchase. The warranty covers defects due to manufacturing issues but does not include damage caused by improper transport, storage, or failure to follow operating instructions.
KOLA current transformers are a reliable choice for those seeking an effective solution for measuring residual currents and protecting power networks from earth faults. Their flexible design, ease of installation, and adaptability to various conditions make these devices an optimal choice for use in industrial and power generation installations.
With KOLA series transformers, you get high measurement accuracy, easy installation, and long service life.