EDP Distribui

1
EDP Distribuição Energia

• ASD Immunization to Voltage Dips
• Case Study in Cement Industry

2
General approach

• Electric utility side
• Protections optimisation
• Split busses and load transfer
• Close of HV meshes
• Customer installations side
• Implementation of high power quality technologies
  with energy storage in critical sectors
• Immunization of sensible equipment through
  software and hardware techniques

3
Cement plant characterization

• Cement plant is supplied in HV (60kV) by two
  independent feeders
• Main loads are mills, fans, compressors and pumps
• The application of ASD in fans presents a large
  energy saving potential and an excellent
  improvement of the process flexibility
• Main fans of the production process are driving
  by ASD

4
Kinetic energy recovery on fans

• Tripping of critical fans with voltage dips can
  cause the whole production process stop
• We are attending the implementation of KER
  technique in cement industry
• This ride-through technique was applied only in
  ASD that drive critical fans
• Voltages and power of machines
• Voltage 690V and 400V
• Power 800kW, 216kW, 200kW and 160kW

5
ASD behaviour with voltage dip
AC Voltage
100
50
t1
t
t2
t3
t1 t3 Voltage Dip
t2 t3 Kinetic Energy Recovery
6
Conclusions

• In the cement plant the voltage dips severity is
  lower (supplied in HV)
• Kinetic energy recovery is an easy and fast
  immunity technique without investment
• The analysis period after implementation is still
  reduced but we hope a better operation
• The ride-through capability improvement should
  start in critical loads