Fluid Insulated High Voltage Coil External Access
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Solution Overview
Problem
High voltage transformers with internal surge arresters are difficult to inspect, replace, or test without draining the oil from the transformer tank, making it challenging to manage voltage stresses and access electrical components.
Innovation Solution
A high voltage coil with a removable column-like electrical interaction device and insulation tube that allows external access, enabling easy inspection, replacement, and testing of surge arresters, and includes electric contact elements connected to the taps for safe and secure electrical interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surge arresters are installed inside the transformer tank under oil, then over-voltage protection is provided, but accessibility for inspection, replacement, or testing becomes difficult
Solution Approach 1:
The transformer system is segmented into two distinct environments: the oil-filled tank for electrical insulation and a separate accessible chamber (insulation tube) for housing surge arresters and measurement devices. This segmentation allows surge arresters to be protected from over-voltages while remaining accessible for maintenance without draining the transformer oil.
Solution Approach 2:
An insulation tube acts as an intermediary structure connecting the oil-filled transformer tank with the external environment. This tube provides a pathway for electrical connections while maintaining isolation between the oil environment and the accessible surge arrester chamber, enabling easy access without compromising electrical insulation.
2Reliability
If surge arresters are installed inside the transformer tank, then they can protect against over-voltages, but testing or measuring of voltages requires draining oil
Solution Approach 1:
The insulation tube serves as an intermediary that allows voltage measurement devices to access tap points without penetrating the oil-filled tank. Measurement devices can be inserted into the tube from the external accessible chamber, enabling voltage measurements while the transformer remains filled with oil.
Solution Approach 2:
The insulation tube structure serves multiple functions: it provides electrical insulation, houses surge arresters, accommodates measurement devices, and maintains accessibility. This multi-functionality eliminates the need for separate structures for protection and measurement.
3Reliability
If tap changers and surge arresters are positioned inside the tank, then electrical insulation is maintained, but components become inaccessible without major effort
Solution Approach 1:
The system is divided into the sealed oil-filled tank for insulation and an external accessible chamber within the insulation tube for maintenance operations. Surge arresters and measurement devices are positioned in the accessible chamber, allowing replacement and testing without draining oil or opening the tank.
Solution Approach 2:
The insulation tube extends vertically from the tank, creating a new spatial dimension for accessibility. Components can be accessed from the top or side of the tank through the tube opening, transforming a three-dimensional internal arrangement into a two-dimensional accessible interface on the tank surface.
Data Source
AI summary
Exemplary embodiments include a fluid insulated high voltage coil having closed tank for an insulation fluid and a high voltage coil arranged therein with at least two taps. An insulation tube extends into the tank, where the inner part of the tube is accessible from an outer side of the tank. Electric contact elements extend through the tube walls along its longitudinal axis, where at least some of the contact elements are electrically connected with the taps. A removable column-like electrical interaction device is arranged within the inner part of the insulation tube, which is electrically connected to the at least two taps by means of the contact elements.