The type, distribution, and variability of electrical loads directly determine the number, configuration, and specialization of transformers required. Rational matching based on load properties avoids overload risks, reduces energy waste, and ensures reliable power for critical equipment.
Primary loads (e.g., emergency lighting, critical production machinery) and secondary loads (e.g., office equipment, non-essential production lines) require uninterrupted or short-interruption power supply. When these loads account for a significant proportion of the total demand, install two or more dry-type transformers in parallel. This redundant configuration ensures that if one transformer is disconnected for maintenance or fails, the remaining units can fully cover the power needs of both primary and secondary loads. Additionally, prioritize concentrating primary and secondary loads in specific areas rather than scattering them across multiple locations—this simplifies wiring, reduces line loss, and makes load management more efficient.
Seasonal loads (e.g., air conditioning systems in summer, heating equipment in winter, or irrigation pumps in agricultural settings) exhibit sharp fluctuations throughout the year. Installing a dedicated dry-type transformer for these loads eliminates the need to oversize general-purpose transformers to accommodate peak seasonal demand. This approach optimizes capacity utilization during off-peak periods, reduces no-load losses, and lowers long-term operational costs.
Concentrated loads (e.g., large industrial motors, high-power production lines, or data center server clusters) draw substantial current in a single location, which can cause voltage drops and stability issues if powered by shared transformers. A dedicated dry-type transformer for such loads ensures stable voltage output, minimizes interference with other electrical systems, and enhances the overall reliability of the power grid. This is particularly important for equipment sensitive to voltage fluctuations, as it prevents performance degradation or damage.
In scenarios where lighting accounts for a large portion of the total load (e.g., shopping malls, stadiums, or commercial complexes), using a shared transformer for both power and lighting may lead to voltage fluctuations. These fluctuations can compromise lighting quality (e.g., flickering) and shorten the lifespan of lamps. If such impacts are significant, install a dedicated dry-type transformer for lighting systems. In most general scenarios (e.g., office buildings, small commercial spaces), a shared transformer suffices to balance cost-effectiveness and practicality.
The operating environment directly affects the safety, durability, and performance of dry-type transformers. Choosing a transformer with appropriate structural and protective features ensures it can withstand environmental challenges while maintaining optimal operation.
In environments with standard temperature, humidity, and no special safety constraints (e.g., independent or attached substations of factories, mines, agricultural and animal husbandry facilities, or residential quarters), both oil-immersed and dry-type transformers are viable options. The selection can be based on factors such as cost, maintenance requirements, and space availability—dry-type transformers are preferred for indoor installations or areas with strict fire safety regulations due to their flame-retardant and explosion-proof properties.
Multi-storey and high-rise main buildings have limited space, dense personnel, and strict fire safety requirements. Select non-combustible or flame-retardant dry-type transformers to eliminate the risk of oil leakage and fire propagation. Dry-type transformers use solid insulation materials (e.g., epoxy resin) that do not release flammable substances, making them ideal for indoor installations in high-rises, where fire safety is a top priority.
Locations with heavy dust (e.g., construction sites, cement factories) or high concentrations of corrosive gases (e.g., chemical plants, coastal areas with salt spray) can damage transformer windings and insulation, leading to reduced performance or failures. Choose closed-type dry-type transformers for these environments—their sealed structure prevents dust accumulation and corrosive substances from entering the core and windings, effectively extending the transformer’s service life and ensuring safe operation.
When dry-type transformers are installed alongside high-voltage and low-voltage power distribution devices that are oil-free and non-oil-immersed, the transformer must be equipped with a protective casing. The casing provides a physical barrier to prevent accidental contact with live parts, ensures compliance with electrical safety standards, and maintains a neat, organized installation layout.
The capacity of a distribution transformer must be accurately matched to the actual electrical demand to avoid underutilization or overload. A scientific capacity selection balances energy efficiency, investment costs, and operational reliability.
First, calculate the total calculated load by integrating the rated capacity of all electrical equipment in the facility—note that fire-fighting loads are generally excluded from this calculation, as they are only activated in emergency situations. Next, consider reactive power compensation measures (e.g., installing capacitors) to improve the power factor; the apparent power after compensation serves as the core basis for selecting transformer capacity and quantity.
A widely accepted practical guideline is to set the transformer load rate at approximately 85%. This load rate balances efficiency and redundancy: it ensures the transformer operates within its optimal efficiency range (reducing energy loss) while leaving sufficient margin to accommodate short-term load fluctuations or future load growth. This method is simple and effective for capacity estimation in most industrial, commercial, and residential applications.
By integrating load characteristics, environmental conditions, and capacity calculations, you can select a dry-type transformer that meets both current needs and long-term operational goals—delivering reliable, efficient, and safe power supply for your facility.
