My experience in solving problems in the cracker plant using a high-speed bus transfer solution

Description of installation

Incoming power supply details: Two of 6.6kV voltage lines are connected to the cracker plant from the distribution substation through reactors. Captive power plant (electricity generation facility) consists of two 36MVA gas turbine generators, two 5MVA steam generators, and two 33kV grids connections in floating mode.

Load details: Four distribution transformers, six 750kW cooling water pump motors, four 630kW feed water pump motors, two 400kW quench water pump motors, and two oil quench pump motors are connected to plant load bus.

Table of contents:

1. Problem definition
2. Solution for the above problems
   1. High-speed bus transfer
      1. Fast bus transfer method
         1. Sequential transfer
         2. Simultaneous transfer
      2. In-phase transfer
      3. Residual voltage transfer
3. Inputs, initiation conditions and blocking interlocks
   1. Inputs required for high-speed bus transfer connection
   2. Conditions which initiate high-speed bus transfer algorithm
   3. Interlocks to block fast bus transfer
4. Problems encountered during installations
   1. Problem #1
   2. Problem #2
5. Advantages of high-speed bus transfer protection

1. Let’s define the problem

Problem #1

Cracker plant is the mother plant for the site, and continuity of power supply is an absolute priority. Though we have a captive power plant that ensures continuity of power most of the time, there are odd cases where the conventional auto-transfer scheme is operated, which resulted in a break in power supply and eventually resulted in a slowdown in production.