Transformer Cooling Layout for Low-Loss Natural and Forced Circulation
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Solution Overview
Problem
Large transformers in photovoltaic power plants face continuous no-load losses due to energization at night, leading to auxiliary machinery losses from constant operation of unit coolers, and using radiators for self-cooling increases transformer size.
Innovation Solution
A stationary induction apparatus with a core, winding, tank, refrigerant, radiator, and unit cooler, where the radiator provides natural air-cooling and the unit cooler forcibly circulates refrigerant for high-load conditions, allowing the unit cooler to be stopped during low loads, reducing auxiliary machinery losses and transformer size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a unit cooler with forced circulation is used as a cooling device, then cooling efficiency is improved, but auxiliary machinery loss increases due to continuous operation of pump and fan during night no-load conditions
Solution Approach 1:
The system dynamically switches between forced circulation cooling (unit cooler with pump and fan) and natural circulation cooling (radiator) based on load conditions. During day-time high-load conditions, the unit cooler operates to provide efficient cooling. During night-time no-load conditions, the system transitions to natural circulation through the radiator, eliminating the need for continuous pump and fan operation, thus reducing auxiliary machinery loss while maintaining adequate cooling capability.
2Loss of energy
If a radiator with self-cooling capacity is used instead of a unit cooler, then auxiliary machinery loss is reduced, but the radiator must be installed over a large area resulting in increased transformer size
Solution Approach 1:
The invention merges both cooling systems into a hybrid configuration: a compact radiator providing natural circulation cooling is integrated with a unit cooler providing forced circulation cooling. The radiator handles base cooling requirements during no-load conditions, while the unit cooler supplements during high-load conditions. This combination allows the radiator to be smaller than a standalone natural circulation radiator would need to be, reducing overall transformer size while maintaining energy efficiency during low-load operation.
3Area of stationary object
If a small radiator is used for natural cooling, then transformer size is suppressed, but cooling capability during high load conditions is insufficient
Solution Approach 1:
The cooling function is segmented into two distinct systems with different operating modes: the radiator handles natural circulation during low-load conditions, while the unit cooler with pump and fan handles forced circulation during high-load conditions. This segmentation allows each subsystem to be optimized for its specific operating range, enabling the radiator to be compact while the unit cooler provides supplemental cooling capacity when needed, achieving both size reduction and adequate cooling performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses the increase in size of the transformer while minimizing auxiliary machinery losses by using a small radiator for natural cooling during low loads and forced cooling during high loads.
Implementation Method 1
a first heat exchange unit capable of naturally air-cooling the refrigerant that is naturally convecting while allowing the refrigerant to flow therethrough
Implementation Method 2
a second heat exchange unit to forcibly air-cool the refrigerant that is being forcibly circulated while allowing the refrigerant to flow therethrough
Data Source
AI summary
A stationary induction apparatus includes a core, a winding, a tank, a refrigerant, a radiator, and a unit cooler. The winding is wound around the core as a central axis. The tank contains the core and the winding. The refrigerant is filled into the tank. The radiator is mounted to the tank and includes a first heat exchange unit capable of naturally air-cooling the refrigerant that is naturally convecting while allowing the refrigerant to flow therethrough. The unit cooler is mounted to the tank and includes a pump to forcibly circulate the refrigerant, and a second heat exchange unit to forcibly air-cool the refrigerant that is being forcibly circulated while allowing the refrigerant to flow therethrough.