S13(22)-M.ZT On-load Automatic Capacity-regulating Distribution Transformer

Scope of Application

This product is applicable to the on-load automatic capacity and voltage regulating distribution transformers with a rated frequency of 50Hz, a voltage class of 10kV, and a three-phase rated capacity ranging from 100(30)kVA to 630(200)kVA.

Product Introduction

The S13(22)-M.ZT on-load automatic capacity and voltage regulating distribution transformer features two rated capacities (large and small). The automatic capacity regulating controller automatically detects and judges the actual load of users, and through a specially designed on-load capacity and voltage regulating switch, it realizes automatic switching between the two capacities without power outage of the transformer. This enables the automatic adjustment of the transformer's operating capacity during operation, thus achieving the automatic conversion between the two rated capacity operation modes.

Purpose and Scope of Application

The S13(22)-M.ZT on-load automatic capacity-regulating distribution transformer is suitable for places with strong seasonal electricity consumption, large load fluctuations, concentrated power usage and low annual average load rate. In China, rural electricity consumption is mainly concentrated in summer and autumn, with lighting being the primary power demand in other seasons. During the busy agricultural seasons, transformers often operate in an overloaded state; while in the off-peak electricity consumption periods, the low load rate leads to the phenomenon of "a large horse pulling a small cart". Therefore, the on-load capacity-regulating distribution transformer is especially suitable for the renovation of rural power grids. In addition, it is also applicable to residential communities with significant differences in electricity load between daytime and nighttime, as well as enterprises and public institutions operating on a regular daytime working schedule.

Basic Working Principle

When the on-load automatic capacity-regulating distribution transformer operates at the large capacity mode, its three-phase high-voltage windings are configured in delta connection (Δ connection) and the low-voltage windings adopt a parallel structure. When it operates at the small capacity mode, the three-phase high-voltage windings are configured in star connection (Y connection) and the low-voltage windings adopt a series structure.

The star-delta conversion of the high-voltage windings and the series-parallel conversion of the low-voltage windings are all accomplished by the on-load capacity-regulating switch, whose switching is determined by the automatic controller according to the detected load conditions.

When the transformer switches from the large-capacity mode to the small-capacity mode, the number of coil turns increases by a factor of 1.7, leading to a substantial reduction in the core magnetic flux density. This results in a lower unit loss of the silicon steel sheet and a significant drop in no-load loss and no-load current. Consequently, the transformer’s no-load reactive power loss (the no-load reactive power loss in the small-capacity mode is less than one-tenth of that in the large-capacity mode) and active power loss (the no-load loss in the small-capacity mode is less than one-third of that in the large-capacity mode) are greatly reduced, achieving the goal of energy conservation and consumption reduction.