A technical and economical comparison was carried out for selection of turbine start-up mode and arrangement of its bypass system of 1 000 MW extra supercritical units in Zouxian Power Plant.

7/537/537-4 turbine as an example,this paper makes the brief introduction to the start-up process of IP cylinder,analyzes and summarizes the start-up mode of IP cylinder by comparisom with that of other type units.

The over-voltage calculation and analysis of the basic operating conditions under the start-up mode and the conventional condition after putting into service were carried out, which can reach to change the start-up mod.

The paper introduces AC Softing Start principle,the soft starting mode,combines the characteristics of belt conveyor,notes chooseing soft starting benefits in belt conveyor application.

Taking the start mode of reclosing in CSL160B series digital series protective devices as the examples,this paper analyzes the differences between this kind of starting mode and conventional tarring mode of reclosing,and probes into the existing problems,and advances some solving methods.

Wherefore,it is very important of the appropriate starting mode to decrease the transformer capacity and ensure the security of starting.

Through changing the starting method of a test unit for a three-phase motor,the constraint relationship between the test unit and the production power load can be solved,thus the starting can be done at any time,and the energy can be saved.

,and points out the notices of IP start and HP start,and compares the merits and demerits of the two start modes.

Based on the relationship between protection mode and the transient stability, this paper proposes the control strategy of over-voltage protection, and studies the start mode of protective bypass.