Transformer Tank Magnetising Current Limiting Device
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Solution Overview
Problem
Existing high-voltage electrical equipment, such as distribution transformers, face challenges in managing magnetising currents during energization, voltage increases after fault isolation, and parallel energization, leading to excessive current peaks that can trigger false fault protections and require external systems for limiting, which occupy space and necessitate frequent operations, causing wear and aging of switchgear components.
Innovation Solution
Integration of an internal device within the transformer tank, comprising operating positions, switching current limiting elements, and start-up/shut-down impedance, allowing for voltage regulation and magnetising current limitation without external systems, reducing space requirements and maintenance needs, and enabling connection/disconnection from the distribution network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external systems are used to limit magnetising current, then magnetising current can be limited, but space is occupied and maintenance is required
Solution Approach 1:
The patent combines the magnetising current limiting function with the transformer tank itself by integrating a limiting device (resistor and contactor) within the tank structure. This eliminates the need for separate external limiting systems, reducing space requirements and maintenance complexity while maintaining the current limitation function.
Solution Approach 2:
The transformer tank is designed to provide its own magnetising current limitation capability through integrated components. The limiting device is automatically activated during energisation without requiring external control systems, making the system self-sufficient and reducing external dependencies.
2Reliability
If pre-insertion resistors are used to limit magnetising current, then overvoltage during switching is limited, but frequent operations cause wear and aging of switchgear components
Solution Approach 1:
The patent extracts the magnetising current limitation function from the main switchgear operation sequence by using a separate contactor (16) dedicated solely to the limiting device (15). This allows the limitation to occur without engaging the main circuit breaker, reducing wear on primary switchgear components while still providing protection during energisation.
3Reliability
If resistors are used to limit magnetising current, then current peaks are reduced, but contactors for connection/disconnection are required
Solution Approach 1:
The patent merges the limiting device (resistor and contactor) within the transformer tank structure, combining multiple functions (current limitation, switching control) into a single integrated assembly. This reduces the number of separate components and simplifies the overall system architecture while maintaining effective current control.
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
The internal device effectively limits magnetising currents, reduces the operational burden on switchgear, extends the life of electrical components, and allows for compact installation without altering the transformer's arrangement, enhancing operational efficiency and reducing wear on circuit breakers and fuses.
Implementation Method 1
a second start-up/shut-down current limiting element (18), which corresponds to the start-up/shut-down position of the transformer, said second start-up/shut-down current limiting element being connected/disconnected by means of the operating means of the device for limiting the magnetising current
Implementation Method 2
a tank (3) with a dielectric medium (4) that at least partially fills said tank (3)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The high-voltage electrical equipment of the invention has means for limiting the magnetising current which arises when a transformer is energised, upon re-establishing a system when the voltage suddenly increases after having isolated a fault or when two transformers are energised in parallel, as well as connecting/disconnecting the equipment from the electric power distribution network or selecting the number of coils of a primary winding in order to obtain the adjustment of the voltage in a secondary winding, for which it mainly has a tank (3) inside of which it has a dielectric medium (4) and a device (2) for limiting the magnetising current that in turn has at least one operating position (5, 6, 7, 8, 9, 10, 29) per phase, at least one operating medium (11, 12) per phase, and at least one first switching current limiting element (17) per phase.