Punjab State Transmission Corporation Limited
(A Punjab Government Undertaking)
About Us : O/o Chief Engineer/SLDC
Particulars of Organisation of Chief Engineer/SLDC , function and duties

Punjab State Load Dispatch Centre (SLDC), now a separate accounting unit of Punjab State Transmission Corporation Limited (PSTCL), is a state of art Computerized Control centre established in August 2002 at Ablowal, Patiala. It ensures integrated operation of the power system of Punjab with the Northern Region Load Dispatch Centre of India.

Under Section 31 of the Indian Electricity Act, 2003 it is mandatory for the States to establish their own Computerized State Load Dispatch Centres for performing the following functions (as specified under Section 32 of Indian Electricity Act 2003): -

  • To ensure integrated operation of the Power System in the State.
  • Optimum dispatch of Electricity.
  • Monitoring and control of system parameters to maintain healthiness of the Power System at all times.
  • SLDC shall keep accounts of the quantity of electricity transmitted through State grid.
  • Exercising supervision and control over the intra-State transmission system.
  • SLDC may levy and collect such fee and charges from the generating companies and licensees engaged in intra-State transmission of electricity as may be specified by the State Commission.
  • Analysis of tripping/disturbances and facilitating immediate remedial measure

SLDC organization has following Departments :

  1. SLDC Operations
  2. SLDC Projects
  3. Open Access
SLDC Operations

In the post unbundling scenario, this office is responsible for the following operations:

  • Optimum scheduling and dispatch of electricity within the state.
  • Monitoring grid operations
  • Keeping accounts of quantum of electricity transmitted through state grid.
  • Exercising supervision and control over the intra state transmission system.
  • Carrying out real time operations for grid control and dispatch of electricity within the state through secure and economic operation ofthe State grid in accordance with Grid Standards and State Grid Code.
SLDC Projects


Supervisory Control and Data Acquisition /Energy Management System (SCADA/EMS) commissioned by M/s. Power Grid Corporation of India Limited (PGCIL) in Northern Region on Unified basis is operational at SLDC, Patiala since 2002 and real time status of the grid is available to the load dispatchers around the clock which further helps them to take corrective actions for operating the grid in efficient manner. For better viewing of data at control centre, a large display screen i.e. Video Projection System (VPS) has been installed. Further to ensure Uninterrupted Supply to the SCADA/EMS hardware, the provision of Uninterrupted Power Supply (UPS) of sufficient capacity has been made at the control centre. Existing SCADA/EMS related hardware and software supplied by M/s Areva has been upgraded by M/s Siemens System. Provision of backup control centre for main SLDC control centre has been made under the new system installed by M/s Siemens Ltd.

Integration of RTUs with the SCADA/EMS:

At present, RTUs at 91 Nos. of 220kV & 132kV substations of PSTCL have been provided with RTUs for remote data acquisition and control from the hierarchy of Control centres i.e. Area Load Control Centres at Jamsher (Jalandhar) & Lalton Kalan (Ludhiana) and State Load Control Centre at Ablowal (Patiala) in Punjab. Besides RTUs, data is being acquired from 7 Nos. SAS (Substation Automation Systems) at 400kV Substations & IPPs. Recently, tender for the Design, Supply, Commissioning and Integration of RTUs at 45 Nos. S/stns (i.e. New RTUs at 35 Nos. S/stns, Retrofitting RTUs at 3 Nos. S/stns and Cannabalizing RTUs at 2 Nos. RTUs) has been awarded vide Tender Enquiry No. SLDC/122/2014. And they are expected to get commission during FY 2017-18.

Implementation of Intrastate boundary metering cum Transmission Level Energy Audit Scheme in PSTCL

Under this project, 750 No. Availability Based Tariff (ABT) meters and 450 No. Conventional Energy Meters (CEM) have been procured. ABT meters have been installed at interface/boundary points of PSTCL with PGCIL, BBMB, HP, PSPCL & IPPs to calculate the amount of energy transmitted through boundary points and for calculation of overall transmission losses of PSTCL. Energy Losses are being calculated from Jul-2017 onwards by energy accounting cell. Also, CEMs have been installed at 400KV, 220KV and 132KV substations of PSTCL for energy audit purposes. Further, Centralized Energy Centre (CEC) of PSTCL has been established at Ablowal, Patiala. The Site Acceptance Test (SAT) of this project has been started and this project is likely to get commissioned within few months. 

Open Access

Open Access office under Chief Engineer/SLDC, PSTCL, Patiala is a nodal agency in state power utilities for grant of short term open access to all eligible customers & consumers of PSPCL.

Open Access is being granted in discriminatorily by PSTCL to all the eligible open access customers embedded in Transmission and Distribution system of PSTCL & PSPCL as per provisions of Electricity Act-2003 and Open Access Regulations issued by Punjab State Electricity Regulatory Commission (PSERC) and Central Electricity Regulatory Commission (CERC) from time to time.

Open Access office also deals with the UI/ Deviation Settlement based energy accounting of Open Access customers transacting power on short term basis and IPPs selling power to PSPCL on long term basis. Besides records are maintained for energy scheduled under short term open access, UI/ Deviation and assessment of open access charges.

Present Status (as on 21.10.2017)

Medium Term Open Access for inter-state wheeling of power has been granted to 1 no. captive consumer (Total 7 MW)

Short Term Open Access for wheeling of power has been granted to 1 no. captive consumer for inter-state wheeling and 2 no. captive consumers for intra-state wheeling of power from their own Captive Power Plant(s) under bilateral transactions. (Total 24.9 MW)

Short Term Open Access for inter-state purchase of power through collective (power exchange)/ bilateral transactions has been granted to 442 no. Large supply consumers of PSPCL (Powercom) (total 1832 MW approx.), out of which 63 no. active consumers with a total STOA granted for 553 MW (approx.) have valid consent as on date. These consumers are purchasing power through power exchange based on their day to day requirement and market trend.

Punjab State Transmission Corp. Ltd.
Regd. Office, PSEB Head Office,
The Mall, Patiala
CIN: U40109PB2010SGC033814
Last Updated: Aug 26, 2019
Managed by O/o SE/IT, PSTCL, Patiala    © PSTCL, All Rights Reserved.