1. Introduction Energy conservation and consumption reduction are important measures to improve the economic efficiency and competitiveness of enterprises. The petroleum and petrochemical industry is a pillar industry of the national economy and also one of the major energy-consuming industries. Energy conservation, consumption reduction, cost reduction, and efficiency improvement are important issues currently facing oilfields. For oilfield enterprises, the main energy consumption products are crude oil, natural gas, electricity, and refined oil products, among which electricity accounts for the largest proportion of total energy consumption, reaching about 48%. The annual electricity cost of an oilfield accounts for about one-third of its total production cost. Therefore, we take the safe operation of the power grid and energy conservation and consumption reduction as our starting point, focusing on strengthening scientific management and technological innovation, actively promoting the application of new energy-saving and consumption-reducing technologies and processes in the power distribution system, enhancing the power grid's disaster resistance capabilities, improving the safe and economical operation level of the power grid, and reducing energy consumption. 2. Current Status of the Power Distribution System in Gudong Oilfield The power distribution system of Gudong Oilfield is responsible for supplying electricity to the five major systems of the oilfield: mechanical oil production, water injection, oil and gas gathering and transportation, heating furnaces, and boilers, as well as the daily electricity needs of all plant employees. It currently has 47 6 kV and 10 kV power distribution lines, including 44 6 kV lines with a total length of 380 km and 3 10 kV lines with a total length of 30.7 km. The 6 kV lines are mainly distributed within the Gudong area, while the 10 kV lines are mainly distributed in the Xintan area. There are a total of 1097 distribution transformers, including 563 energy-saving transformers with a capacity of 56725 KVA and 534 non-energy-saving transformers with a capacity of 90915 KVA. See the attached table for the installation and usage status of the oilfield transformers. [ALIGN=CENTER][IMG=Oilfield Transformer Installation and Usage Status]/uploadpic/THESIS/2007/7/2007071813204742274L.jpg[/IMG] Attached Table: Oilfield Transformer Installation and Usage Status [/ALIGN] In 2004, the total energy consumption of the entire plant reached 287,624 tons of standard coal, and the total electricity consumption reached 43,019.6832 x 10⁴ kW•h, accounting for approximately 30% of the total energy consumption of the entire plant. Based on the energy consumption statistics of the oilfield in previous years, with the increasing difficulty of developing old oilfields and the decrease in the average newness coefficient of system equipment, the efficiency of the oilfield power distribution system is showing a downward trend, while the electricity load is showing a certain upward trend. If corresponding effective measures are not taken, it will seriously affect the improvement of the economic benefits of petroleum development enterprises and restrict the sustainable and stable development of the oilfield. 3. Application of energy-saving and consumption-reducing technologies in the system 3.1 Energy-saving management technical measures (1) Strengthen electricity management and reduce power loss In order to strengthen electricity management, based on investigation and research, the responsibility for electricity management of power lines is divided among the three grassroots units according to the actual situation of electricity load. The management responsibility boundaries between the oilfield's electricity management department and the three grassroots units are clarified, and detailed management methods and work processes for new installations and capacity expansion are formulated. In terms of internal electricity management, the comprehensive indicators of electricity consumption of all 6kV lines are decomposed layer by layer, and a daily meter reading and ten-day analysis system is implemented. The cause of large fluctuations in electricity consumption is immediately investigated. In terms of the management of employees' living electricity, employees are actively guided to establish a resource-saving awareness. All office water heaters are turned off at the end of the workday, air conditioners are controlled at an appropriate temperature, timers are installed in appropriate locations, and phenomena such as lights and electric heating tubes left on are eliminated. Energy-saving management is carried out from the smallest details. In terms of managing external electricity consumption order, electricity transfer users must strictly follow the electricity transfer approval procedures for approval, filing, metering, and timed settlement. At the same time, efforts should be made to control the increase of electricity transfer users, increase the investigation and punishment of illegal and irregular electricity use, and eliminate illegal electricity use points, which has achieved good control results. (2) Do a good job in peak shaving and valley filling electricity management . The oilfield power supply department settles the electricity price for electricity users in three time periods: industrial peak period, industrial flat period, and industrial valley period. The electricity price for the industrial peak period is settled at RMB 0.72 per kilowatt-hour, the electricity price for the industrial flat period is settled at RMB 0.48 per kilowatt-hour, and the electricity price for each industrial period is settled at RMB 0.24 per kilowatt-hour. The oilfield implements peak shaving and valley filling operation mode management for each drainage pumping station. It is stipulated that under normal circumstances, each drainage station can only start pumping drainage within 8 hours of the industrial valley period, and pumping drainage should be stopped at other times. (3) Reducing the capacity of power distribution equipment Transformers are the main equipment in the internal power supply and distribution network of the oilfield, and their power loss accounts for 50% to 70% of the internal power supply and distribution network loss. Reasonable selection of transformer capacity is the key to ensuring the safe and economical operation of the oilfield power supply system. According to the current electricity fee standard of RMB 11 per 1 KVA capacity per month, in addition to taking measures to reduce electricity consumption, it is more important to reduce the total capacity of distribution transformers to reduce the expenditure of basic electricity fees. By taking measures such as replacing large-capacity transformers with smaller ones, recycling idle transformers, and suspending seasonal power equipment, the capacity of our plant's distribution transformers was reduced from 246,950 KVA at the beginning of 2000 to 162,051 KVA at the end of 2004, a total reduction of 84,899 KVA in 5 years. This alone reduced the oilfield 's electricity expenditure by more than RMB 11 million. (4) Strengthening the management of air conditioner use Strengthening the management of air conditioner use plays a significant role in controlling the growth of electricity consumption. According to statistics, our factory currently has more than 2,000 air conditioners of various types, with a capacity of about 3,800 kW. By adopting the management regulations for the use of air conditioners to control their operation at appropriate temperatures and strengthening supervision and management, the electricity consumption can be reduced by 3,000 kWh per unit in summer. 3.2 Energy-saving technical measures (1) Introducing live-line working technology to improve the reliability and safety of power grid supply Since 2000, our factory has introduced and applied live-line working technology in the 6-10 kV power grid. Live-line working technology is applicable to both eliminating defects in the power grid and carrying out power grid maintenance. Operational practice shows that implementing live-line working on the power grid can not only greatly improve the reliability of power supply, but also reduce the impact on crude oil production caused by line outage maintenance, bringing huge economic benefits to the oilfield. From a safety perspective, because the protective measures during live-line working are very complete, even if you step on the wrong pole, there will be no safety accident. However, the safety measures during power outage maintenance are set according to the equipment being de-energized. Once you step on the wrong pole, it may cause personal injury or death, with unimaginable consequences. Therefore, from a safety perspective, live-line maintenance is superior to power-off maintenance. (2) Replace high-energy-consuming transformers with new energy-saving transformers . The SII type transformer is a new type of energy-saving transformer and is currently the most advanced oil-immersed transformer in China in terms of economic and technical indicators. Compared with the S7 type transformer of the same capacity, it has the advantages of less no-load loss, less load loss and less no-load current percentage. Therefore, under the same operating conditions, the SII type energy-saving transformer is more economical and practical than the S7 type transformer. From 2000 to 2004, our factory promoted the application of SII type energy-saving transformers to replace the original S7 transformers, totaling 560 units. According to statistics, the annual electricity saving reached 1.5 million kWh, and the annual operating electricity cost was reduced by an average of 29.2%. Compared with the S7 type transformer, the SII type energy-saving transformer saves 35% of electricity. (3) Apply high-voltage maintenance-free wide-limit metering devices . There are many large electricity users on power lines, whether high-voltage or low-voltage. The electricity meters of these users are configured according to the normal load of the transformer. When the load is within the normal range, the electricity meter can achieve the calibrated accuracy. When the load is small, the metering error increases. In this case, the application of a high-voltage maintenance-free wide-range metering device can effectively solve the problem of small load metering. Its metering range can be 1000 times wider. It adopts a high-efficiency metering chip from the United States and is equipped with an electronic automatic switching segmented current transformer to achieve accurate metering throughout the entire current range. At the same time, it also has a remote automatic meter reading function and is equipped with an advanced GPRS communication module to realize remote automatic meter reading from the master station. When an abnormal state is detected, it can transmit the data to the master station to provide technical support for finding the cause. (4) Application of power consumption monitoring and energy-saving optimization system Real-time monitoring of 40 transformers on the 6kV South Line 3 and Middle Line 3 is carried out, and the operating parameters of each transformer are statistically analyzed, which greatly improves the automation level of power metering and ensures the safe and economical operation of the power grid system. Its main functions include: real-time monitoring, fixed-point monitoring, report generation, over-limit alarm, historical data query, data release, data analysis and parameter setting. The system mainly consists of two parts: the EDA9033E series intelligent power transmitter and the system master station. The EDA9033E series intelligent power transmitter is an intelligent three-phase electrical parameter data acquisition module. One is installed on each transformer. It can display data locally and transmit data remotely. The system master station uses a round-robin method to monitor the transformers under its jurisdiction and saves the collected data in the database. It can detect three-phase voltage, three-phase current, active power, reactive power, power factor, frequency, active power of each phase, reactive power of each phase, forward active energy, reverse active energy, forward reactive energy, and reverse reactive energy in real time. (5) Upgrading and transformation of the distribution network In 2001, the voltage of the original distribution network of Xintan Oilfield was upgraded from 6 kV to 10 kV. After the renovation, not only was the load-carrying capacity of the power grid increased (power supply capacity increased by about 66%), but the network loss of the distribution network was also greatly reduced, reducing annual power loss by 400,000 kWh. Simultaneously, the power quality at the network's end was improved, ensuring the needs of oilfield production and effectively changing the history of relying on oil tankers to transport crude oil from wells, achieving good economic benefits. Furthermore, to improve the reliability of power supply to the two major blocks north and south of the Yellow River, a cable project crossing the Yellow River was implemented as a connecting line between the two blocks, forming a dual-power supply system. This ensured the normal operation of crude oil production, reduced power outages, and decreased the annual outage time in the region from 200 hours to 20 hours, increasing annual crude oil production by approximately 9,500 tons and generating over 8 million yuan in benefits. In 2004, the 6KV South Line 2 of the Gudong Oilfield underwent technical renovation. This line originally had 38 transformers with a capacity of 3,965 kVA and 92 oil wells. Due to the large line load, frequent line breaks and power outages occurred, seriously affecting oil well production. Through technical transformation, the South Second Line was divided into two parts, with one part each driven by the East First Substation and the East Sixth Substation. This achieved load diversion, reduced line losses, improved the safety operation coefficient, avoided line breakage accidents caused by excessive load, reduced power outage time, and ensured oil well production. (6) Application of reactive power optimization compensation technology Power factor is an important indicator reflecting the rational use of electrical equipment, the degree of power utilization, and the level of power management by power users. Reactive power has certain adverse effects on power supply and consumption, mainly manifested in: first, reducing the active power output of generators; second, reducing the power supply capacity of transmission and transformation equipment; third, increasing line voltage loss and power loss; and fourth, causing low power factor operation and voltage drop, which prevents the full utilization of electrical equipment capacity and reduces the actual working capacity of equipment. In 2004, due to insufficient reactive power compensation, the power factor of 25 power lines in our plant was lower than 0.85. The average power factor of the 44 power lines in the Tong plant was only 0.805. To improve the power factor of the power grid, reactive power optimization compensation technology was applied. Based on the reactive load and distribution in the grid, and following the principles of "combining overall balance with local balance; combining decentralized compensation with centralized compensation, with decentralized compensation as the main focus; and combining loss reduction with voltage regulation, with loss reduction as the main focus," reactive power compensation equipment was rationally selected and the distribution of compensation capacity was determined. Compensation capacity was promptly allocated, and dynamic tracking analysis was implemented, thereby reducing power loss. 4. Conclusion The application of energy-saving and consumption-reducing technologies in the oilfield power distribution system has significantly improved the level of automation technology in oilfield power distribution, increased the safety and reliability of the oilfield power grid, improved the power supply capacity and quality, reduced line losses, and achieved good energy-saving and consumption-reducing effects, resulting in significant economic and social benefits. (Article sourced from "Energy Saving Innovation 2006—Proceedings of the First National Electrical Energy Saving Competition")