2. Power Quality during the late 90’s  PQ was dominated by Fluke and LEM  Power Utilities has just started talking about standards to be followed  National Power Corporation, Meralco - main proponents in the utility companies involved in setting up the standards  A very few manufacturing companies are aware of the need of PQ for their facilities

3. Power Quality in the 2000’s  More players came in (RPM, Dranetz-DMI, Hioki, EIG, AEMC, Unipower, etc)  Philippine Grid Code was published and started to be implemented (2001)  Philippine Distribution Code was published and started to be implemented (2001)  TransCo was separated from the National Power Corporation (2003)  National Power Corporation, TransCo, Meralco - became models in the PQ standardization

4. Power Quality in the 2000’s (cont..)  Privatization of the government owned Power Plants  TransCo became the National Grid Corporation of the Philippines (NGCP)  Models for PQ originates from NGCP and Meralco using the PGC and PDC as basis for the standards  Manufacturing facilities engineers became aware of the need to implement PM involving PQ

5. Grid Code PQ Requirements  Power Quality Performance (Article 3.2)  System Frequency Deviation  Voltage Magnitudes Variations  Voltage Fluctuations  Harmonic Frequencies  Voltage Unbalance  Transient Voltage Variations

6. Grid Code PQ Requirements  Frequency Variations  Nominal Frequency – 60 Hz  Maintain Frequency during normal conditions  Limits: 59.4 Hz ≤ f ≤ 60.6 Hz

7. Grid Code PQ Requirements  Voltage Variations  Long Duration Voltage Variation Duration greater than 1 minute Undervoltage (RMS value is less than or equal to 90% of the nominal value) Overvoltage (RMS value is greater than or equal to 110% of the nominal value) 95% ≤ RMS nominal voltage ≤ 105%

8. Grid Code PQ Requirements  Voltage Variations  Short Duration Voltage Variation Duration greater than ½ cycle but not exceeding 1 minute Voltage Swell (RMS value increases between 110% and 180% of the nominal value) Voltage Sag (RMS value decreases between 10% and 90% of the nominal value)

9. Grid Code PQ Requirements  Voltage Fluctuation  Random amplitude changes of RMS value between 90% to 110% of the nominal voltage  Voltage fluctuation shall not exceed 1% of the nominal voltage for every step change, which may occur repetitively  Large voltage fluctuation other than a step change maybe allowed up to 3% provided will not put risk to the Grid or any User system

10. Grid Code PQ Requirements  Flicker Severity  Short Term Flicker Severity (P ST ) – short duty cycle fluctuation,shall be computed over a 10- minute period  Short Term Flicker Severity (P LT ) – long and variable duty cycle fluctuation, derived from P ST levels

11. Grid Code PQ Requirements  Harmonics  Total Harmonic Distortion (THD) – ratio of the RMS value of the harmonic content to the RMS value of the fundamental quantity in percent

12. Grid Code PQ Requirements  Harmonics  Total Demand Distortion (TDD) – ratio of the RMS value of the harmonic content to the RMS value of the rated or maximum fundamental quantity in percent

13. Grid Code PQ Requirements  Voltage Unbalance  Refers to negative sequence unbalance factor or zero unbalance factor Negative Sequence Unbalance Factor = Negative Sequence Components of Voltages Positive Sequence Components of Voltages Zero Sequence Unbalance Factor = Zero Sequence Components of Voltages Positive Sequence Components of Voltages  Compliance: Voltage Unbalance ≤ 1% for 115 kV and above Voltage Unbalance ≤ 2.5% for 69 kV and below

14. Grid Code PQ Requirements  Transient Voltage Variations High frequency overvoltages shorter in duration compared to short duration voltage variations In-frequent short-duration may exceed levels of harmonics limits provided such increases do not compromise service to End-users or cause damage to Grid equipment In-frequent short-duration with a maximum value of 2% maybe permitted for Voltage Unbalance subject to terms of Connection Agreement

15. END OF PRESENTATION THANK YOU