Like a test of the heart

In the days of May, the summer sun in the context of El Nino is strong and lasts like a fire that covers everything. Endless ups and downs on the street, everyone is covered in clothes, hats, gloves, masks, sunglasses.

Using remote-controlled unmanned aerial vehicles (UAV) with image recording equipment and specialized cameras in power grid management and operation at Lam Dong Power Transmission. Photo: Ngoc Ha/Icon.com.vn. From mid-morning to late-afternoon, the heat reached more than 40 degrees Celsius, blowing hot air in every corner from the countryside to the city, the demand for electricity increased continuously for many days and the transmission grid always at the full load warning threshold. In order to ensure the safe operation of equipment on the transmission grid, the National Power Transmission Corporation (EVNNPT) requires units to strengthen the inspection and monitoring of transformers, resistance, current transformers, etc. voltage transformers, pole clamps, connections on lines, substations. In particular, special attention should be paid to the full-load 500kV transformers such as Viet Tri, Hoa Binh, Nho Quan, Thuong Tin, PleiKu 2, Dak Nong, Vinh Tan and the North – Central 500kV lines. Troubled hot season Deputy Director of Power Transmission Company 3 (PTC3) Ho Cong said that by May 2021, the total installed capacity of solar power will be connected to the PTC3 transmission grid and the distribution grid of Power companies in the region. the area of ​​the provinces: Khanh Hoa, Phu Yen, Binh Dinh, Gia Lai, Dak Lak and Dak Nong has reached 4,093MW, accounting for 36% of the total installed capacity of power sources connected to the transmission and distribution grids in the region. this. In which, the connection at the voltage level of 500kV is 600 MW, at the voltage level of 220kV is 753 MW, at the voltage level of 110kV is 940 MW, and the farm and rooftop solar power connected at the voltage level below 22kV is 1,801 MW. With the very fast development speed of solar power plants, farm solar power, rooftop solar power in a short time, some 220kV transmission lines have been built in Phu Yen, Binh Dinh, Gia Lai and Dak Lak areas. and Dak Nong always operate at full load, overload occurs in the rainy season of the Central Highlands. Especially the 220kV transmission lines: Sinh Mass An Khe – Pleiku (100%); An Khe Biomass – An Khe Hydropower Plant (100%); Quy Nhon – An Khe Power Plant (99%); Quy Nhon – Tuy Hoa (96%); Tianjin – Nha Trang (98%); Nha Trang – Krong Buk (87%); Krong Buk – Pleiku 2: (88%) Dak Nong – Buon Tuahar (102%); Dak Nong – Buon Kuop (99%) and AT1 transformer (97.%), AT2 (96%) 500kV Dak Nong substation; transformer AT1 (94%), AT2 (95%) 500kV Pleiku 2 station; transformer AT1 (100%), AT5 (94%) 500kV Pleiku station… When the power grid is operating in a state of full load or overload, PTC3 must request units to increase the frequency of inspection and monitoring of equipment, transformers, lines and corridors to promptly overcome and handle handle unusual phenomena. In addition, some repair and maintenance works that need to be cut off or periodically tested must be arranged at night when solar power stops generating. The implementation of safety measures, as well as the process of construction supervision, supervision of load-bearing equipment, safety control at poles that cross with medium and low voltage lines and roads at it is dark, at night it will be very difficult, potentially dangerous. Khanh Hoa Power Transmission installed an AI camera to warn of fire in the corridor of the 220kV line: Nha Trang – KrongBuk. Photo: Ngoc Ha/Icon.com.vn According to the document No. 795/TTg-CN dated June 25, 2020 of the Prime Minister on adding the list of wind power projects to the electricity development planning, wind power plant projects in the Central Highlands region. with a total capacity of 2,358MW (accounting for 21% of the total installed capacity of power sources connected to the transmission and distribution grids in this area) is in the process of construction, installation, and putting these projects into operation. November 2021 will put more pressure on the existing transmission grid, which is already full and overloaded in the provinces: Khanh Hoa, Phu Yen, Binh Dinh, Gia Lai, Dak Lak and Dak Nong. In particular, in Gia Lai area, there is a total capacity of 1,242.4MW (voltage level 500kV: 200MW, 220kV: 650MW, 110kV: 392.4MW); Dak Lak area has a total capacity of 685.8MW (voltage level 500kV: 400MW, 220kV: 200MW, 110kV: 85.8MW); Dak Nong area has a total capacity of 430 MW (voltage level 220kV: 380MW, 110kV: 50MW), when put into operation, it will continue to overload 220kV lines of Yang Trung – Pleiku 2 wind power plant; An Khe – Pleiku Biomass, An Khe Biomass – An Khe Hydropower Plant; An Khe – Quy Nhon Hydropower Plant; Krong Buk – Pleiku 2, Dak Nong – Buon Tua shar, Dak Nong – Buon Kuop and AT1 and AT2 transformers at 500kV Dak Nong substation; AT1, AT2 500kV Pleiku substation 2. As a line soldier, the sun also goes to the line, the rain also goes to the line, as a station soldier, flood, or hot weather must be on duty 24/24. In order to mobilize sources effectively, in the current conditions, EVN requires the Power Transmission Companies to transmit the maximum mobilized capacity of the power plant cluster at 100% until the congestion or overload is reached. The associated load is removed. With this requirement, the new operating status of the PTC3 grid is often at 100% full load. Thus, it is necessary to keep the current flowing smoothly in all situations, especially on hot sunny days. With a “hot” area like PTC3, all units, regardless of whether they were on duty or off duty, must gather their manpower to check the grid’s congestion points, the points with high risk of heat generation. The point of line cross-section is small compared to the whole line, the rated current of the equipment in the exposed compartment is smaller than the line, the points have a large deflection, the risk of breaking the distance when the load is high..etc and so on and so forth. problems can occur when the temperature reaches more than 40 degrees Celsius and lasts for many days. It can be said that the transmission shifts during the heat wave are no different from the ones on duty during the flood season. After detecting the risk, it is necessary to propose to reduce the rated current of the line; if the ambient temperature rises suddenly, it is necessary to monitor that the conductor temperature does not exceed the allowable level; make a plan for temporary handling and a plan for long-term handling of bottlenecks of the power grid, determine the time for remediation, and submit it to the Company. For example, during the recent heat wave in May, the transmission units must make statistics of the number of enhanced inspections from the beginning of 2020, thereby proposing a reasonable plan to arrange human resources for the new operation situation; propose the addition of production equipment and tools to serve the operation management in the new operating situation, make a list of proposed equipment to be added immediately. A place to test people’s hearts Using remote-controlled unmanned aerial vehicles (UAV) with image recording equipment and specialized cameras in power grid management and operation at Lam Dong Power Transmission. Photo: Ngoc Ha/Icon.com.vn. Head of PTC3 Dispatch Department Nguyen Manh Tuong said that in the first 5 months of 2021, the electricity output received by the PTC3 transmission grid under management and operation reached 23,918,261,392 kWh, an increase of 16.30% over the same period in 2020; delivered electricity output reached 23,445,807,704 kWh, up 16.10% over the same period in 2020; power output received on the 500kV grid reached 17,223,481,412 kWh, an increase of 26.40% over the same period in 2020; electricity output delivered on the 500kV grid reached 17,000,463,190 kWh, up 26.26% over the same period in 2020; power output received on the 220kV grid reached 13,549,084,784 kWh, up 29.86% over the same period in 2020; electricity output delivered on the 220kV grid reached 13,299,649,317 kWh, up 30.08% over the same period in 2020. Despite this output, the transmission output of Power Transmission Company 3 (Khanh Hoa, Phu Yen, Binh Dinh, Gia Lai, Dak Lak, Dak Nong, Ninh Thuan, Lam Dong, Binh Thuan power transmission lines) assigned to Power companies under the Central Power Corporation (EVNCPC), the South (EVNSPC) and power plants (ND, DT, Solar, EIA) in the first 5 months of 2021, reaching 2,826,264,307 kWh, down 37.85% over the same period in 2020, accounting for 49.18% of commercial electricity output of 9 Power companies. The highest transmission power output in May is May 16, 2021 at 22,436,520 kWh. The main reason for the decrease in transmission power output is due to the performance of commercial power production of Khanh Hoa, Phu Yen, Binh Dinh, Gia Lai, Dak Lak, Dak Nong, Ninh Thuan and Lam Power companies. Dong and Binh Thuan under the Central Power Corporation (EVNCPC) and the South (EVNSPC) in the first 5 months of 2021 reached 5.746 billion kWh, a low growth rate, reaching only 0.67% over the same period in 2020. Meanwhile, the electricity output of 110kV solar power, 22kV farm solar, 0.4kV rooftop solar, small and medium hydroelectricity power generation to the distribution grid of 9 Southern Central and Western Power companies Originally belonging to EVNCPC, EVNSPC increased sharply in the first 5 months of 2021, reaching 5.010 billion kWh. The transmission output of renewable energy sources, medium and small hydroelectricity from the distribution grid, in addition to meeting the load demand of the Power Companies, is also transmitted to the transmission grid at 220kv substations of the Transmission lines. Khanh Hoa, Phu Yen, Binh Dinh, Gia Lai, Dak Lak, Dak Nong, Ninh Thuan, Lam Dong, Binh Thuan in the first 5 months of 2021 are 2.090 billion kWh, which means that the renewable energy output is reversed. to the transmission grid from the distribution grid of the power companies. Thus, the transmission grid under the management of PTC3, in addition to receiving power from the 500kV system and 220kV power plants in the area to supply loads, also receives back-generated output from the distribution grid through the distribution networks. 220kV transformers connected to the national grid cause full load, overload the 220kV grid. This is also one of the reasons for the full load situation for the regional transmission grid, and at the same time brings about the paradox in the operation of PTC3 that the transmission grid managed by PTC3 always operates in a poor condition. state of full load, overload, but the commercial power output did not meet the delivery plan. This shows that there has been an inadequacy when the planned transmission power output is not counted when the renewable energy output is back to the grid. Despite such difficulties, PTC3’s employees are always committed to the power grid and are responsible for their work. They memorized the characteristics of each area of ​​the transmission grid, each compartment of the substation. In the dry season, which columns are at risk of fire due to trees in the corridor. In the rainy season, which pillars are prone to landslide. Which residential areas often fly kites, stretch canvas to dry agricultural products… Just entering the third day of the second heat wave of summer 2021, the national electricity consumption capacity at noon on June 18, 2021, has reached a new peak of 41,709 MW, the PTC3 transmission soldiers are again straining themselves with the harsh climate. of the southern central provinces and the Central Highlands, with the transmission grid always in a state of 100% full load, but not allowing problems due to subjectivity – that is the duty and also the command from the soldier’s heart. Electricity transmission. The current must be kept smoothly despite the unresolved inadequacies, because the story of the mechanism, in order to be removed, still has to be discussed, considered, must be appropriate…and the mission of the transmission soldier is Under any circumstances, the current must be maintained. Because the difficulties that PTC3 is going through is also to test people’s hearts.