Lessons learned from implementing path operating limit computation using the state estimator node/breaker model

Path operating limit calculations utilizing real time State Estimator cases provide a more accurate path operating limit. Changes to the operating condition will result in the need to recalculate a new set of Path SOLs. The real time State Estimator (SE) node/breaker model provides actual system conditions and also aids to model contingencies more accurately based on the operating conditions. Reliability is not compromised and the revenue is not impacted due to conservative limits using the proposed approach. It is important to tune the SE to reflect the actual conditions to achieve meaningful results. The approach presented takes care of thermal, voltage and contingency constraints. So it is not necessary to run thermal studies and voltage studies separately. The results are encouraging and the approach can be extended to calculate the real-time path operating limit every fifteen minutes using the real time SE cases, future hour cases and also on demand for real-time operations. Interesting results are presented how path operating limits vary within a day.