Yaas Headwinds: Model disaster management efforts by Odisha power utilities to weather the storm

Model disaster management efforts by Odisha power utilities to weather the storm

Gagan Bihari Swain, Director (Finance & Corporate Affairs), GRIDCO Limited

The first message regarding the formation of a low pressure area over the east central Bay of Bengal came from the India Meteorological Department (IMD) six days before Cyclone Yaas hit on May 26, 2021. The impact was huge and the damage was extensive. Power supply to over 3 million consumers was disrupted. More than 100,000 distribution transformers were rendered out of order and around 1,200 11 kV feeders were affected. The restoration task was humongous, but was completed within five days.

Many challenges

Mobilising manpower and carrying out restoration activities was a major challenge, especially given that the daily active Covid-19 caseload was mounting hugely and the entire country, including Odisha, was in lockdown. Power supply to oxygen manufacturing and refilling plants was being monitored by the central and the state government. Odisha was supplying oxygen to Andhra Pradesh, Telangana, Tamil Nadu, Chhattisgarh, Maharashtra, Haryana, Punjab, Uttar Pradesh, Madhya Pradesh, Bihar and Delhi at a daily average of 556 mt. There are 36 key oxygen manufacturing and refilling plants operating in the state. Any power failure to these units would hamper production and supply of oxygen. Meanwhile, the list of critical installations kept increasing. Quick restoration of thousands of primary health centres (PHCs) and community health centres (CHCs) was the need of the hour as Covid vaccines are stored in these centres besides critical Covid patients.

This was the time of year when humidity goes up to above 90 per cent. Continuous rain followed by cyclone and storm water ingress flooded hectares of land, including the electrical network. Besides, inaccessible roads and a difficult terrain made it difficult to carry on restoration work. Poles and equipment had to be moved by float, on small vessels and at times on workers’ shoulders.

The new management of distribution utilities – TPNODL, the most affected utility, started operations on April 1, 2021. The new management was not equipped to manage disasters of this extent and was also unaware of the region’s geography. Some of the other challenges, as faced in past cyclones, were preventing accidents from the back charging of DGs, lightning, etc., procurement of a large quantity of material in a very short time, lack of availability of skilled manpower and modern pole erection equipment, logistical arrangements such as lodging, food and drinking water facilities for workers, public unrest for quick power restoration, etc. The government gave directives to ensure “zero casualties”, but with thousands of people working in swampy waterlogged fields, ensuring the safety of every workman was a big challenge.

Cyclone impact

Heavy wind gusts coupled with storm surges of 4 metres followed by incessant rain affected the coastal districts of Balasore, Bhadrak, Kendrapada, Jagatsinghpur and Jajpur, and the northern districts of Keonjhar and Mayurbhanj. Over 300 mm of rainfall was recorded in these districts and the low-lying areas were flooded. The districts of Angul, Dhenkanal, Cuttack, Nayagarh, Khurda and Puri were partly affected as the cyclone system moved towards the north-western borders of the state. Electrical infrastructure in Balasore and Bhadrak was critically affected.

The distribution infrastructure, particularly 33 kV, 11 kV and LT lines, and distribution transformers suffered heavy damage. Around 170 nos. of 33 kV feeders, 366 nos. of 33/11 kV substations, 1,201 nos. of 11 kV feeders, 105,004 nos. of distribution transformers and around 3.03 million consumers were affected. About 1,500 MW load crashed in the state power system, which is about one-third of the state’s average demand.

Preparedness was the key

Odisha has a coastline of about 480 km along the Bay of Bengal and is prone to cyclones. The frequency and intensity of cyclonic storms have increased over the years causing large-scale damage to power infrastructure. In the past two decades, Odisha has faced eight major cyclones. Generally, Odisha faces cyclones in the summer months (pre-monsoon) and the winter months (return of monsoon). Extensive damage takes place to the power distribution network due to open construction over the ground, vegetation and wire tension, etc. owing to whirlwinds and heavy rainfall. Power utilities started preparatory activities in early April 2021 in anticipation of the summer cyclone. After receiving a cyclone alert, the following preparation measures were taken up prior to the cyclone making landfall:

  • Control rooms were set up at the state and utility level for monitoring grid supply, infrastructure damage, resource mobilisation, response and restoration coordination, dissemination of regular cyclone updates from the IMD, MIS preparation and coordination with the State Disaster Management Authority, Energy Department and Ministry of Power, etc.
  • Regular tracking of weather information was undertaken (on an hourly basis) for getting advance weather information such as expected wind speed, cyclone intensity, storm surge, rainfall, likely affected area and landfall location.
  • Areas that could get affected by the cyclone were identified and the vulnerable T&D infrastructure mapped. Accordingly, strategic locations and clusters were identified and formed.
  • Advance mobilisation of manpower and vehicles was undertaken. Coordination with other utilities was undertaken for additional manpower deployment.
  • Coordination with neighbouring states was undertaken for standby arrangements of emergency restoration system (ERS) towers. Manpower mobilisation from other states was avoided in view of the Covid-19 pandemic.
  • Mobilisation and prepositioning of cranes, excavators, transportation, safety equipment, T&Ps such as pole-mounted tractors, pulleys, cable jointing tools, gas cutters, emergency lights and other tools and tackles, portable DG sets, fuel, etc. were undertaken.
  • Locations were identified for setting up sub-stores and roadside fabrication units, free community kitchens and lodging arrangements for workmen involved in restoration.
  • Preventive maintenance such as pruning of tree branches, strengthening of weak distribution links and other risky installations was carried out.
  • Advance funds were placed with electrical circles and divisions, and circles for emergency local procurement. Enlisted vendors, existing EPC contractors and rate contract holders were contacted for early despatch of men and material as per requirement.
  • SAT phones were provided at discom head offices and divisions.
  • WhatsApp groups were created for quick circulation of information.
  • Suppliers were informed to maintain the required inventory of materials and fuel.
  • ERS towers, poles, DTRs and other spares/equipment were pre-positioned for T&D substations at possibly affected locations based on the cyclone path.
  • A fully functional backup state load despatch centre (SLDC) was operationalised at the Meramundali 400 kV STU grid station at Angul, about 100 km from the main SLDC at Bhubaneswar.
  • Meetings were held with generators, the SLDC, ERLDC, major industries and important consumers (water supply, telecom, hospitals, banks, railways, airports, state and district headquarters, etc.) for planning of grid management, systematic reduction and subsequent restoration of electrical loads, and revising the islanding scheme and black-start procedure, if required, as communications could fail when the cyclone moved inland.
  • Restoration standard operating procedures (SOPs) were issued with indicative measures for preparedness and post-cyclone response.
  • MIS reporting formats were prepared and assigned to the nodal officers.
  • The damage and restoration plan was pre-assessed, based on the predicted wind speed. This was updated based on the latest information.

Alternative power supply arrangements were made to all oxygen production and refilling plants. Fail-safe power supply arrangements were made for all six large oxygen generating plants, although they have their own captive generating units. The balance 30 plants were provided with DG sets, enough diesel for withstanding a seven-day power failure and a full shift operator, so that plant operations were not hampered. Similar actions were taken for Covid hospitals and care centres.

Steps taken during the movement of the cyclone

  • Immediate shutdown of 11 kV or 33 kV feeder lines as per protocol.
  • Generation managed in order to achieve optimum grid parameters and prevent a blackout.
  • Emergency response teams functionalised.
  • Consumers notified about power outages and safety measures.

Safety measures

  • It was decided to temporarily switch off the power supply of the respective feeders when wind speeds exceeded 40-50 km per hour.
  • The State Relief commissioner issued an order prohibiting the connection of DG sets by individuals for private purposes from 6 a.m. to 6 p.m. while the power restoration work was in process to avoid any accident due to back current from DG sets.
  • Personal protective equipment such as safety helmets, discharge rods, hand gloves and safety belts were provided before the execution of work.
  • Discoms were instructed to strictly adhere to the SOP for post-cyclone restoration works and to maintain ground clearance, vertical clearance and horizontal clearance between lines and substations as per the guidelines.
  • Instructions were given to maintain Covid-appropriate behaviour and ensure the use of masks and sanitisers at worksites and labour camps. Large-scale vaccination of electrical employees was undertaken. Rapid antigen testing of workmen was carried out prior to deployment and after completion of work to prevent the spread of Covid-19.

Material and manpower mobilisation

Around 550 vehicles, 300 DG sets, 200 cranes and 50,000 poles were mobilised/ lined up for ramping up restoration work. Over 10,000 additional workmen were mobilised, besides 5,000 utility staff for completing the supply restoration within five days. Machinery such as pole masters, tractors and rollers were put to use to prevent the spread of Covid and prevent workmen fatigue. Wage rates were enhanced 1.5 times of the notified wage along with daily food charges to retain workmen. Pre-positioning of men and material in proportion to the expected damage to the power network and quick administrative decisions significantly reduced the restoration time.

Restoration activity

Once the storm receded, SDRF teams, along with patrolling parties, were mobilised to clear roads and debris, assess the damage and carry out local restoration work. Material, manpower and logistical support were scaled up in critical damaged areas as soon as the preliminary damage reports were available. RS joist poles were used instead of PSC poles for easy movement and faster restoration. Separate groups were formed for HT and LT restoration work. The focus was on carrying out parallel works to minimise reconstruction time. Improved coordination with the local administration prevented law and order situations during restoration activities.

Coordination and concerted efforts by all stakeholders were catalytic in instilling the desired synergy in restoration activities. Senior officers were deputed to the affected field divisions. Late evening reviews were conducted through video conferencing for daily situation monitoring progress and next-day planning.

Power supply was restored to all district headquarters and Covid hospitals within eight hours. Grid supply to oxygen plants was restored within 12 hours. Power supply was restored to all block headquarters in the affected districts within 24 hours of the cyclone landfall. Around 80 per cent of the public water works and PHCs/CHCs were restored within 48 hours.

Disaster management strategy 

Time was really short. The formation of the depression and the cyclone striking land had just three days in between. The prediction of the landfall area and cyclone intensity gave a lead time of only 48 hours. Different predictions were made by the IMD and INCOIS on the line of cyclone movement and landfall location, which made it more difficult and entailed frequent changes in strategy till the final location was known. But the state authorities and utilities managed to weather the storm because of the disaster management acumen accumulated over the years. The factors that made the key difference are:

  • Strong administrative support from the state machinery, quick decisions on emergency wage rates, enhanced transportation charges, operationalising state-level control rooms, deployment of dedicated NDRF/ODRAF groups were critical.
  • With the predicated landfall location and the cyclone path and intensity, the possible impact area and vulnerable infrastructure were pre-assessed and mapped with electrical networks.
  • Tree trimming was completed in a large number of feeders prior to the cyclone; this helped in minimising the damage.
  • The feeders were segregated, based on the severity of damage and the material mobilised and prepositioned, estimating 50 per cent damage in these locations.
  • Material and manpower mobilisation was ramped up within three days and 10,000 manpower and 50,000 poles were pre-placed/planned by the morning of May 26 before landfall.
  • It was a big task to mobilise and optimally deploy 10,000 workmen with tools and tackles and engage them simultaneously with the 5,000 in-house staff. The workforce was mobilised from non-affected utilities and tagged with the respective feeder managers. Nearly 500 engineers were deputed to supervise the field work. Managing the mobilisation and deployment centrally helped in quick scaling up.

Notably, the utilities ensured zero casualties due to electrical hazards during the cyclone and post-cyclone restoration works. The Ministry of Power has acknowledged the state’s preparedness and response measures during the pre-cyclone, cyclone landfall and post-cyclone periods for effective mitigation and quick power supply restoration. In fact, the Coalition for Disaster Resilient Infrastructure (CDRI), an international coalition of countries is studying the Odisha model of disaster management. Since the Super Cyclone in 1999, the state has enhanced its disaster management capabilities to ensure zero fatality and mitigate disaster after-effects, which has been acknowledged by international agencies such as the United Nations Office for Disaster Risk Reduction on multiple occasions. N