Project Description

Steel Melting & Rolling Industry

TYPE OF INDUSTRY – Steel Melting & Rolling Industry Yemen. Middle East Asia.

YEAR OF IMPLEMENTATION – 2010

PROBLEMS

Plant was operating on Captive Generation of 58 Mw. The Plant are having Medium Frequency Induction Furnaces, LRF and Rolling Mills with Oxygen plants. Plant was having following issues.

  • Low power factor
  • Not able to operate Furnaces & Rolling Mill together.
  • Poor Plant Loading Factor.
  • Frequent Electrical breakdown
  • Heating of transformer and cables.

OBSERVATIONS

After conducting Power Quality Audit in the plant, following observations are made:

  • Total Harmonic Distortion (THD) Voltage is high > 10 % . The higher order Harmonics like 11th , 13 th & 23 rd etc are predominant which generate high voltage distortion.

  • Power factor in Rolling Mill is low < 0.70 due to DC drives and 5th & 7th Harmonics are Predominant due to use of 6 Pulse Converter.

  • Due to High Harmonics distortion, the Generators are not able to operate at full load.

SOLUTION

  • Tuned Harmonic Filter Banks at 11 KV Main Bus to control THD <5 % as per IEEE 519-1992 .

  • Automatic Harmonic Filter Banks on Rolling Mill Transformers.

  • IGBTs Based Static Var Generators to control Leading PF on 11 KV bus.

Project Implementation

  • Design, Manufacturing & Installation of Passive Tuned Harmonic Filters at 11 KV Main Bus.

      • 5th Tuned Harmonic Filter Banks -2600 kvar , 15.20 KV , 3phase , 50Hz
      • 7th Tuned Harmonic Filter Banks -1300 kvar , 15.20 KV , 3phase , 50Hz
      • 11th Tuned Harmonic Filter Banks -6064 (3032 k x 2no)  kvar , 15.20 KV , 3phase , 50Hz

  • Design, Manufacturing & Installation of Automatic Harmonic Filter Banks on Rolling Mill & Oxygen plant Transformers – 1500 kvar /525 V – 2nos.

  • Design, Manufacturing & Installation of IGBTS Based Static Var Generator +/- 750 kvar , 440 V to inject Inductive & Capacitive Kvar to avoid over compensation on Generators.

RESULT

  • THDI & THDV reduced to < 3% at main 11 KV Bus
  • PF improvement to 0.99 lag .
  • Avoid Leading PF on 11 KV Bus .
  • Increase Loading Capacity of Generators. Hence Furnaces & Rolling Mills both can  operate Simultaneously .
  • Increase Plant Productivity.