Tap changer pdf

The impedance mentioned above can either be resistive or reactive. The tap changer with a resistive type of impedance uses high speed switching, whereas the reactive type uses slow moving switching. High speed resistor switching is now the most popular method used worldwide, and hence it is the method that is reviewed in this report. The tapped portion of the winding may be located at one of the following locations, depending upon the type of winding:.

The most common type of arrangements is the last two. This is because they give the least electrical stress between the tap changer and earth; along with subjecting the tapings to less physical and electrical stress from fault currents entering the line terminals. At lower voltages the tap changer may be located at either the low voltage or high voltage windings.

Tap changers can be connected to the primary or secondary side windings of the transformer depending on:. Star, delta or autotransformer — Position of tap changer in the winding — Losses associated with different tap changer configurations eg.

Coarse tap or reverse winding — Step voltage and circulating currents — Cost — Physical size. Transformers are one of the more expensive pieces of equipment used in a power system, and the potential consequences of failure can be quite damaging. This has been shown in the past with the political and media attention surrounding blackouts at various locations around the world.

Within Australia and New Zealand, the largest cost transformer failures have occurred due to internal winding faults, faulty load tap changers, and failed winding accessories respectively. Failure of winding accessories includes loose coil clamping bolts, together with internal winding faults and faulty tap changers.

This figure was considered conservative because there are many other factors that could be added on to this figure that are difficult to determine.

It is interesting to note the root of these failures appear to have been predominantly design and manufacturing flaws. During the past years and after a number of visits, meetings, lectures and training courses, the conclusion has been reached that proper organization and execution of OLTC maintenance is found only in very few cases.

The frequency of maintenance to on load tap changers is dependent on the condition of the diverter switch and the necessity to maintain the motor drive unit. Maintenance of the diverter switch should be carried out on a cyclic basis, but on transformers where frequency of tap change is high, maintenance may be necessary before the cyclic maintenance becomes due. A certain period should not be exceeded between inspections.

When considering inspection periods, serious consideration should be given to the breaking of circulating current which in some cases may exceed the load current. The diverter switch and tap selector is the only internal moving parts in a transformer.

The diverter switch does the entire on load making and breaking of currents, whereas the tap selector preselects the tap to which the diverter switch will transfer the load current. The tap selector operates off load and therefore needs no maintenance.

The on-load tap-changer is packed in two parts diverter switch and tap selector and is well protected against moisture. Both parts are locked in the adjustment position. The on-load tap-changer equipment is shipped as follows: Diverter switch oil compartment with on-load tap-changer head and fitted diverter switch insert max.

Post on Aug views. Category: Documents 4 download. NOTE indicates important information on a particular topic. Figure 1 Three-phase on-load tap-changer The diverter switch is installed in its own oil compartment. Figure 4 ED-S. Tshering Nidup, Mr. Penjor, Mr. Dawa Gyeltshen, Mr Capacity in Amphibian Research in Bhutan. Dawa Gyeltshen, Mr. Nub Tshering. Hmoud Mr. Huang Mr. Jalloh Ms. Lehto Mr. Murase Mr Park Mr. Peter Mr. Yasir Maqsood. An upgrade replacement pro Transformer Controls 6.

Alex Otto Mr. Jacob Wolff Mr. Max Grube Mr. Pincus Mr. Jacob Uhlfelder Mr. August Neubauer Mr. Dhwanee Dhanwaria Nayra Kohli Mr. Md Mahmoud Ould Dahi, Cyber forum. MR Bp lb. MR lpm. MR Bp ls. MR Bp pop. MR Bp pt. MR Bp. Sanjib Barman Mr. Manas Roy Mr.

Bipresh Goswami Mr. Bimal Bhattacharjee Mr. Pradip Kumar Sinha. Puri Mr. Chatterjee Mr. Veerabhadra Rao Mr. Venkateswaran Mr.