How to Overhaul a Transformer Core

How to Overhaul a Transformer Core The transformer core serves as the mechanical backbone of the entire transformer and is a crucial component that provides the magnetic circuit for the transformer. Therefore, inspecting the transformer core is a key step in ensuring the safe operation of the transformer. The inspection of the core involves the following 8 steps: 1. Inspect Appearance and Clean the Core Inspect the external appearance of the core for smoothness, checking for any short circuits or discoloration, discharge burn marks, and ensuring that the insulation paint film is intact. Clean the top of the upper yoke and the bottom of the lower yoke from any oil […]

When is it not allowed to adjust the on-load tap changer of a transformer? During the operation and maintenance of a transformer, the adjustment of the on-load tap changer (OLTC) needs to strictly adhere to regulations to ensure the safe and stable operation of the transformer. Here are several situations in which adjusting the OLTC is not permitted: During transformer overload operation: Overloading can cause an increase in internal temperatures, and adjusting the tap changer at this time may lead to insulation aging of the transformer windings or even trigger a failure. However, in special circumstances, such as the need to temporarily adjust the tap changer to ensure grid stability,

What reasons can cause abnormal noise in transformers? During the operation of a transformer, the occurrence of abnormal noise can be attributed to various factors. When the transformer operates under overload conditions, internal copper and iron losses increase, leading to elevated temperatures and reduced heat dissipation. In such situations, the transformer may emit a dull humming sound, caused by saturation of the transformer core and an increase in magnetic flux density. Poor internal contacts in the transformer can result in localized discharge, generating sparking noises. This type of sound is typically sharp and continuous. Loose components within the transformer can also lead to unusual noises. These components may vibrate during

How to Reduce Transformer Core Losses? Transformer core losses primarily include eddy current losses and hysteresis losses. Here is an elaboration on methods to decrease core losses: (1) Optimize core material: To minimize losses, selecting core materials with low losses and high saturation magnetic induction is crucial. Silicon steel is currently one of the most widely used materials for transformer cores, and its silicon content effectively reduces eddy current losses. (2) Employ laminating techniques: Transforming silicon steel into laminated sheets can effectively slow down the formation and propagation of eddy currents, thereby reducing loss levels. This laminating technique contributes to enhancing the performance of the core and reducing energy losses.

What Causes Winding Breakage? There are several reasons that can lead to winding breakage in transformers: (1) Unstable Line Connections: When the winding connections in a transformer are problematic, such as poor welding, inadequate contact, or loosening, it may result in concentrated currents or localized overheating at the connection points. Prolonged overheating can accelerate the aging of internal insulation materials, ultimately causing the winding to break. (2) Various Overvoltages: Overvoltage occurs when the voltage surpasses the normal operating range of the equipment. Elevated voltages can increase electric field intensity, damaging the insulation materials of the winding and potentially causing partial or complete winding breakage. Various forms of overvoltage induce overcurrent

What Causes Overheating of Transformer Core? The overheating of a transformer core can be attributed to several factors: (1) Overload: When a transformer operates under excessive load, the current passing through the core increases, generating additional Joule heating. This can result in an elevated temperature of the core, surpassing the design temperature. (2) Iron Loss: The iron loss of the core is related to the magnetic flux density and frequency during transformer operation. If the operating point deviates from the design point, causing an increase in iron loss, it can lead to overheating of the core. (3) Harmonics: During transformer operation, harmonics in the system can induce overheating of the

How to Approach Transformer Temperature Rise Reasonably? Perspectives on temperature rise encompass various aspects essential for the long-term stable operation of transformers, specifically in the following dimensions: (1) Safety: The prudent control of temperature rise aims to ensure that the internal temperature of the transformer does not exceed safety limits. This measure is primarily intended to mitigate the risk of overheating, effectively preventing potential fire incidents or other malfunctions. (2) Efficiency: Careful temperature rise control contributes to improving the efficiency of transformers. During the design phase, the emphasis is typically on achieving the lowest possible temperature rise to reduce energy wastage and enhance overall energy efficiency. This ensures that transformers

What is the thermal class of a transformer? The thermal class of a transformer typically refers to the thermal stability of its insulation system, a crucial factor directly impacting the temperature endurance during prolonged operation. This classification is commonly denoted by letters such as A, E, B, F, H, each representing a specific maximum temperature level. In the design process of transformers, careful consideration is given to selecting an appropriate thermal class to ensure the transformer maintains excellent performance and reliability under normal operating conditions. Opting for a higher thermal class can enhance the transformer’s load-carrying capacity, but it may also result in increased manufacturing costs. Therefore, a balanced consideration

Maintenance and Fastening of Transformer Body 1. Body Cleaning: Users and manufacturers of transformers have stringent requirements for the cleanliness of the transformer body, making body cleaning crucial. During the assembly process, crucial components, especially insulating parts, require meticulous cleaning. Typically, a vacuum cleaner is used, and clean white cloths are employed for wiping. In cases of oil contamination, the face adhesive method is the simplest and most effective approach. The cleaning outcome necessitates that metallic foreign objects, particularly non-metallic ones, remain invisible. 2. Body Fastening: (1) Re-fasten the upper and lower iron yoke screws and baseplates, ensuring proper placement of washers when tightening bolts and nuts. (2) When fastening the strap

How to Look at TheParallelOperation of Transformers？ The parallel operation of transformers refers to connecting the primary windings of two or more transformers to a common busbar and connecting their secondary windings to a common secondary busbar. Transformers operated in this manner are termed to be in parallel operation. 1. Advantages of parallel operation of transformers include: (1) Meeting Demands of Large Power Grids: Addresses the capacity requirements that a single transformer may find challenging to meet in a large power grid. (2) Enhancing Power Supply Reliability: Improves the reliability of power supply; if one transformer experiences a fault and is disconnected, others can continue supplying power. (3) Adjusting Transformer Quantity Based