Climbing the Power “Sky Road” in the “Three Rivers” Fault Zone

At the end of 2014, the Sichuan-Tibet grid interconnection project — built under the leadership of the State Grid and hailed as the world's most challenging power “sky road” — was successfully put into operation, marking the complete end of the history of isolated grid operation in Tibet's Changdu and southern Garze, and laying a solid foundation for local economic construction and social development to move onto the “expressway.”
The Sichuan-Tibet interconnection project is another major power transmission and transformation project crossing extremely cold, high-altitude areas after the Qinghai-Tibet interconnection project. As the “heart” of a substation, the transformer is crucial, and whether transformer oil suitable for extremely cold environments can be supplied in time is a key link in whether the project can be put into operation.
The safe and smooth commissioning of the Sichuan-Tibet interconnection project also marks that PetroChina Lubricant Company's transformer oil has climbed the power “sky road” in the “Three Rivers” fault zone.
Called upon at a critical moment, helping the isolated grid become “connected” sooner
Tibet's Changdu region grid had long operated in isolation, not only restricting local economic power use but also suffering the pain of outage risks. The Sichuan-Tibet interconnection project is a major construction project under the state's 12th Five-Year Plan to support Tibet's development; it aims to connect the Tibet Changdu grid with the Sichuan grid, fundamentally solving the long-standing power shortage in Tibet's Changdu region and southern Garze in Sichuan, and is of great significance to promoting economic development and social stability in the Tibetan areas.
On June 16, 2014, China XD Group raised with the Lubricant Company's Northwest Sales Branch a requirement for on-site delivery of 273 tons of KI45X transformer oil for 3 transformers and 6 reactors in Changdu, Tibet, and communicated information such as the rugged transport roads, highly variable road conditions and harsh climate in the Changdu area.
China XD Group's Sichuan-Tibet interconnection project includes power equipment such as 500 kV reactors, 220 kV combined transformers, 220 kV capacitive voltage transformers, 110 kV capacitive voltage transformers, 2 amorphous alloy transformers, 15 bays of 110 kV combined switchgear and 5 bays of 220 kV combined switchgear, requiring nearly 300 tons of transformer oil.
China XD Group has had a good cooperative relationship with the Lubricant Company for many years and is also an important strategic partner of the company. After receiving the delivery order, the Northwest Lubricant Sales Branch organized a meeting to specifically study the organization of the Changdu, Tibet delivery, and formulated measures to complete the on-site delivery task by every possible means, ensuring the goal of consolidating the strategic foundation and achieving win-win cooperation.
Kunlun transformer oil from the Lubricant Company is widely used in the domestic power transmission and transformation field for its unique resource attributes and good electrical performance; more than 80% of high-voltage-grade transformers in national key projects in the country's power industry, including the Daya Bay Nuclear Power Plant, use Kunlun naphthenic transformer oil.
Since the Lubricant Company started its delivery business in 2011, it has successively completed delivery tasks for key projects such as State Grid's Hami South–Zhengzhou ±800 kV ultra-high-voltage direct current line, Xiluodu left bank–Zhejiang Jinhua ±800 kV UHV DC line, the “Zhefu” 1,000 kV UHV alternating current line and China Southern Power Grid's “Two Crossings” DC line — but this was the first time they had encountered such an urgent, difficult, dangerous and heavy delivery task.
The Sichuan-Tibet interconnection project officially began construction on March 18, 2014; the Lubricant Company received the order at the end of July and had to deliver all the oil to the site by mid-August. The project lies on the “Three Rivers” fault zone where the Jinsha, Nu and Lancang rivers converge — one of the areas with the world's most complex geological structures and most widespread geological disasters. The project route is more than 1,500 kilometers long, mostly through towering mountains and uninhabited areas, at an average altitude of 3,850 meters.
Based on the views of the special meeting, the Northwest Lubricant Sales Branch quickly set up a “Tibet Changdu Delivery Project Coordination Leading Group,” headed by branch general manager Yang Chen, responsible for overall delivery coordination. Bulk oil department manager Zhao Qiang was responsible for delivery vehicle preparation and specific delivery organization, and Shaanxi specialty oil area manager Bai Zhijun was responsible for communication with XD Group and for determining the specific on-site transformer installation and oil use plan…
A working mechanism of centralized command, unified coordination, linked upper and lower levels and divided responsibilities quickly took shape, and a “trinity” linkage system of the Northwest Lubricant Sales Branch, XD Group and the delivery contractor was established.
Scouting ahead, stopping and going, crossing the river by feeling the stones
At the end of July 2014, the Northwest Lubricant Sales Branch immediately began preparations before delivery. On the one hand, it organized product filtration in accordance with the on-site transformer voltage grade installation standard requirements; on the other hand, it conducted a comprehensive and thorough inspection in advance of the vehicles to be put into delivery service in Tibet, and through the logistics company determined 6 drivers in good physical condition, one of whom was the captain of the transport fleet.
Because the transport fleet lacked experience in transporting into Tibet and time was pressing, the Northwest Lubricant Sales Branch, after consulting travel agencies and searching transport routes online, decided to dispatch two vehicles of product first to scout the way for the entire delivery.
Two tank trucks carrying transformer oil set off on their transport journey along the most reasonable route planned by Baidu Maps. The original plan was to go via Nagqu to Changdu, but after arriving in Nagqu they learned that the road from Nagqu to Changdu is basically used only by tourist off-road vehicles, with extremely poor road conditions, and that at the time it was the rainy season and tank trucks simply could not get through.
To ensure the installation schedule, after re-planning the route the vehicles turned around and headed toward Lhasa, intending to reach Changdu via Lhasa. Facing the challenges of harsh climate and road conditions, the tank truck drivers finally reached Lhasa, only to encounter an overweight bridge that was difficult to cross.
According to local people, even if this bridge could be crossed, there were still dozens of kilometers of mountain road ahead that was a “dead end” — tank trucks simply could not pass the narrow road along the cliff and would be caught in a dilemma.
Misfortunes never come singly. The tank truck drivers were at their wits' end. After repeated communication with the drivers and consultation with a local transport company, the Northwest Lubricant Sales Branch learned that tank trucks could take National Highway 214 via Yushu to Changdu, but because the mountain road is narrow, tank trucks cannot get around many of the curves, so smaller vehicles had to be used for transport.
So the transport drivers changed route again to National Highway 214, heading toward Yushu. At the same time, because exploring the transport route while driving and the earlier wrong turns had wasted a lot of time, the Northwest Lubricant Sales Branch asked the driver responsible for scouting to communicate all the circumstances promptly with the delivery contractor and required subsequent vehicles to switch to smaller-tonnage trucks, otherwise they would simply be unable to proceed in certain sections.
The delivery contractor promptly adjusted the transport vehicles according to actual conditions, and the following 4 vehicles all switched to small vehicles carrying movable storage tanks holding the export product, taking National Highway 214. After the 4 vehicles passed Golmud, road conditions gradually worsened, with some sections still under repair requiring detours, and with the rainy season, they stopped and went all the way. After passing Yushu, they joined up with the 2 scouting vehicles and continued onward.
Overcoming one difficulty after another: turning the delivery “chasm” into an “open road”
After the 6 vehicles entered the mountains, because of the high altitude, apart from the drivers feeling slightly unwell, the vehicles also suffered altitude sickness: power was noticeably insufficient and they could only drive slowly in low gear, keeping the drivers' nerves highly strung and their legs trembling.
After passing Riwoqe, there was a stretch of more than 20 kilometers of particularly narrow mountain road, with mountain on one side and a cliff on the other; with rocks falling continuously in the rainy season, the risk to travelers was extreme. The fleet captain led the way up the mountain; some curves were too narrow, so when turning he could only scrape along the rocks at the mountain's edge, and after passing through, the captain took a shuttle bus back and drove each vehicle through the mountain road one by one. Although the cab roof of one vehicle was struck by a rock falling from the mountain, fortunately no one was injured.
The more than 400 kilometers of mountain road from Yushu to Changdu took the vehicles a full 3 days, and finally on August 16 the transformer oil was safely delivered to the site.
After the oil arrived on site, while waiting for the transformer installation and the results of the oil testing, several drivers, overcoming physical discomfort, stayed at the site the whole time. It was not until the end of August and early September, after the oil was successively injected into the “heart” of the Changdu substation — the transformers — that the drivers drove back.
Recalling the transport process of the entire delivery task, Zhao Qiang of the Northwest Lubricant Sales Branch sighed over the hardships involved and then said with tremendous pride: “The successful use of Kunlun transformer oil deep in the plateau fully reflects the image of PetroChina as a responsible and dependable enterprise; especially when the Sichuan-Tibet interconnection project was smoothly connected to the grid and highly praised by state leaders, I felt very gratified.”