Transmission expansion planning in deregulated market

Transmission expansion planning (TEP) decides where, when and what new transmission lines and substations should be built so that power from generators reaches loads reliably and economically over the planning period. In a deregulated market, generation is built by many private companies, so the transmission planner (system operator/transmission company) must plan under uncertainty and ensure open access.

Inputs

• Load forecast by region/substation (peak MW, energy).
• Generation expansion scenarios: location and timing of IPP plants, cross-border import/export.
• Existing network data: lines, transformers, ratings, impedances.
• Reliability and planning criteria: N-1 security, voltage limits (e.g. ±5%), thermal limits, fault levels.
• Cost data: line cost per km, substation cost, losses, right-of-way.
• Market data: bids, congestion history, locational prices, wheeling charges, regulatory rules.

Process

Load-flow, contingency and short-circuit studies on candidate networks; comparison of alternatives by cost, losses and congestion relief; stakeholder consultation; regulator approval.

Outcome

• Least-cost set of new lines/substations with voltage level, route and commissioning year.
• Reduced congestion, so market prices are uniform and competition is fair.
• Open, non-discriminatory access for all generators and traders.
• Transmission tariff and cost allocation among users.
• Reliable evacuation of IPP power and cross-border trade (e.g. Nepal's 400 kV backbone and Nepal–India links).