Ashlu Creek Impact Study - BC Hydro - Transmission

More documents

Recommendations

Info

4.2 Short Circuit Study Increase in fault levels at remote stations due to Ashlu IPP remains within the existing equipment ratings. Fault Levels expressed as Thevenin Impedances at point-of-interconnection on 2L12 are: Present Fault Level (including Ashlu IPP): Z + = R + + jX + = 2.0 + j18.1 ohms Z - = R - + jX - = 2.1 + j18.5 ohms Z 0 = R 0 + jX 0 = 1.3 + j20.0 ohms Present Fault Level (excluding Ashlu IPP): Z + = R + + jX + = 2.34 + j19.5 ohms Z - = R - + jX - = 2.34 + j19.5 ohms Z 0 = R 0 + jX 0 = 1.7 + j24.1 ohms Ultimate Fault Level: 3-phase fault = 5000 MVA X/R = 10 (assumed) SLG fault: 12.5 kA rms sym. The foregoing assumes 1.05 x the base voltage of 230 kV. This is the minimum level recommended for 230 kV stations for the BCTC system and provides adequate capability for an ultimate 500 – 230 kV tie at Cheekye. The ultimate duty shall be used for the basic station design such as bus strength and ground grid and for any major equipment that the owner does not want to replace when the present fault level increases to the ultimate. No planned date exists for this increase. Ashlu Generator Step-up Transformer It is required that this be configured as a conventional generator transformer with a LV delta to HV grounded wye configuration. The recommended HV nominal tap for this transformer is 236 kV with +/-2 x 2.5% offload taps ________________________________________________________________________________________________________________________________________________ This document contains proprietary information and shall not be reproduced in whole or in part without the prior written consent of BCTC 2
4.3 Power Flow Based First Contingency Study Power flow based single contingency studies do not have any further transmission line loading problem. There is no voltage violation due to the addition of the Ashlu IPP. There is also no voltage stability issue upon loss of the largest load in this area, or loss of the Ashlu IPP. Summary of load flow study results are shown in Table 1. Table 1 Steady State Power Flow Study Results for Ashlu IPP Project System Load Condition 2009 HW 2009 HS 2009 LS 2009 HW System configuration Heavy winter- Normal Heavy summer- Normal Light summer- Normal Heavy winter- 2L13 outage MW Injection from IPP CMS 230 Bus Voltage (in per unit) CKY 230 SQH 60 MAM 60 Power Flow (MW) 2L13 (CKY- CYP) 2L12 (CMS- CKY) 2L9 (CKY- LYN) Comment 55 1.010 0.999 1.067 1.069 203 221 230 Fig. 1 55 1.010 1.013 1.071 1.069 209* 134 132 Fig. 2 55 1.048 1.048 1.085 1.080 54 82 84 Fig. 3 55 1.010 1.000 1.068 1.069 203 outage 363 Fig. 4 * 2L12 is overloaded to 106% summer rating. Present line conductor operating temperature is at 50 deg C. The addition of the Ashlu IPP will require that 2L12 be upgraded for a higher operating temperature. 4.4 Reliability Study There is an existing BC Hydro 173 MVA CMS generating station connected on 2L12 which the Ashlu IPP will be tapped on. A reliability assessment of the connection schemes of employing a disconnect switch (DS) versus a 3 breaker ring (3CB) at the POI has been performed based on line outage data. The unavailability of 2L12 for a 3CB scheme is 1.0 hours/year compared to 1.21 hours/year for a DS scheme. Thus, for a small improvement in reliability (0.21 hours/year) the 3-breaker ring configuration is not required from the system reliability point of view. However, the 2.5 km tap line from the POI to the IPP shall be designed and maintained to the 2L12 level. Otherwise, reliability of the CMS power plant will be reduced to an unacceptable level. ________________________________________________________________________________________________________________________________________________ This document contains proprietary information and shall not be reproduced in whole or in part without the prior written consent of BCTC 3
Page 1 and 2: Ashlu IPP Impact Study June 2006 Im
Page 3 and 4: Ashlu IPP Impact Study June 2006 Ex
Page 5: Ashlu IPP Impact Study June 2006 1.
Page 9 and 10: 4.6 Islanding IPP will be required
Page 11 and 12: Ashlu IPP Impact Study June 2006 Fi
Page 13 and 14: Ashlu IPP Impact Study June 2006 Fi
Page 15 and 16: ESAC8B Basler DECS This model is lo
Page 17 and 18: J + 5 10. T 7 J + 6 2.99 K S2 = T7/
Page 19 and 20: Fig. 6-2 Stability swing of bus vol
Page 21: Fig. 6-4 Stability swing of bus fre

Ashlu Creek Impact Study - BC Hydro - Transmission

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?