Advanced Tapchanger Control Features - and When to Use Them! (Part One)

This paper describes several of the latest "new features and some "older" underused features of advanced LTC (load tap changer) transformers and regulator controls, with a brief description of their proper applications. Available timing options, which can be used to optimize the action of tapchanger controls, are discussed. These include instantaneous reset or integrating timers, sequential operation, non-sequential operation, inter-tap time delay, or pulsed output and definite or inverse time characteristics. The choice of the LDC-Z form of LDC can be extremely important in those system applications where R&X methods are misused or inadequate. These conditions include the use on LTC transformers feeding buses with multiple feeders. In some applications, unintended voltage changes may be experienced as a result of a tapchange in another location on the system. This could result in "hunting" for an appropriate solution to interconnected problems