21.August
Overview of the TPO Series Current Transformers: The Reliable Solution for Outdoor Applications
TPO series current transformers, featuring molded insulation made from hydrophobic cycloaliphatic epoxy resin (HCEP), are an optimal choice for measurement and protection applications in outdoor environments. Thanks to innovative materials and thoughtful design, TPO transformers deliver high reliability, durability, and protection even in extreme climatic conditions.
Key Advantages of TPO
Resistance to External Factors: HCEP insulation offers high resistance to ultraviolet radiation, ozone, and arc faults, ensuring stable operation even in outdoor environments.
Hydrophobic Properties: The transformer surface repels moisture, making these units ideal for humid environments and ensuring reliable performance in the harshest climates.
Multifunctionality: The transformers can be equipped with up to four secondary windings, customizable for different applications—such as measurement, protection, or special testing.
Main parameters
| Parameter name | Units | Parameters |
| Nominal primary current | A | 150 |
| Primary current switching | A | 600 – 1200 |
| Nominal secondary currents | A | 5;1 |
| Rated frequency | Hz | 50 |
| Insulation levels | kV | 36/70/170; 38.5/80/180; 40.5/95/200 |
| Nominal short-term thermal current [1s] | kA | 100 |
| Max. rated load/class | VA/cl | 3 – 60/0,2;0,2S;0,5;0,5S;1;3;5P;10P |
| Ambient temperature | °C | -60 — +55 |
| Reconnection | Primary or secondary | |
Purpose
The TPO series current transformers (models 70.11, 70.12, 71.11, 72.11, and others) are designed for operation in electrical networks up to 35 kV and are suitable for both measurement and protection circuits. These transformers are ideal for outdoor use in moderately cold climates, making them a versatile solution for a wide range of outdoor electrical installations.
Design Features and Operation
To protect against external factors, the transformers are made from hydrophobic cycloaliphatic epoxy resin (HCEP), which provides mechanical strength and reliability. HCEP offers excellent protective properties against ozone, UV radiation, and arc faults.
The TPO series transformers can be fitted with one to four secondary windings, which can be used for measurement, protection, or specialized applications. Grounding one of the terminals of each secondary winding ensures safe operation.
Configuration and Installation
The TPO transformers feature a robust housing secured by four bolts. Suspension lugs are included for easy transportation and installation. The secondary windings are enclosed in a sealed compartment with a hermetically sealed lid, providing additional protection from environmental factors.
The transformers can be installed in any position (vertical, cantilevered, or inverted), offering flexibility in placement. A junction box with a PG21 cable gland is included for easy connection and is an integral part of the design.
Quality Assurance
TPO transformers meet the requirements of IEC 61869-2, ensuring high reliability and accuracy. All test results are stored electronically and are available upon customer request.
Advantages in Use
The TPO series current transformers perform exceptionally well in applications involving frequent line switching and overvoltages. Encapsulated in HCEP, they provide reliable protection and stable operation even in challenging environments such as coastal or polluted areas.
The TPO series transformers are a dependable solution for measurement and protection tasks in power grids up to 35 kV. High-quality materials, resistance to external factors, and adaptability to diverse requirements make these transformers the ideal choice for outdoor applications in any environment.