Dual power supply, dual-circuit high-voltage power supply, can the two incoming lines work at the same time?

Of course, two lines enter at the same time, serving as backup for each other.

Dual power supply management system 1. The following situations belong to dual power supply. 1. Those who supply power to power consumers from two or more lines in the power system from two different substations or power plants (regardless of voltage levels). 2. The power supply is supplied from one line of the power system and the user has his or her own generator. 2. Those who meet the following conditions can use dual power supplies after approval. 1. According to the requirements for the reliability of electrical equipment for the public, a sudden power outage will cause personal casualties or major equipment damage, and bring significant losses to the national economy. 2. It is important * * places of meaning (e.g.: Hotels, municipal-level party, government, and military leaders’ command offices, major transportation and communication hubs, radio stations, TV stations, airports, navigation stations, civil air defense headquarters, important public places, urban water sources, electrified railways, important scientific research departments), operating rooms and emergency rooms of large city and county-level hospitals where sudden power outages may cause personal death risks, etc. 3. A sudden power outage will cause a large number of products and raw materials to be scrapped or a major equipment accident will occur. 4. A sudden power outage caused gas explosions in underground coal mines and flammable and explosive military and defense factories, causing a large number of casualties. 3. Procedures for electricity consuming units to apply for dual power supply. 1. Users who require dual power supply should submit written applications to the Electric Power Bureau's Electricity Utilization Office and Rural Electricity Office respectively. The Electricity Utilization Office and Rural Electricity Office are responsible for investigation, and the proposed power supply plan will be reviewed with the Biotechnology Unit, District Regulation and other relevant departments. After approval by the deputy director of production of the bureau, the Rural Electricity and Electricity Departments will reply to the user respectively, and a copy will be sent to the relevant units for records. 2. For users who have their own generators, they should apply to the Electric Power Bureau and submit a wiring diagram before the generator is put into operation. After passing the inspection and issuing a power generation and use certificate, it can be put into use. 3. Any dual power supply involving another power supply range must be approved by the Biotechnology Department of Yangquan Power Supply Bureau. 4. If the utility load of the electricity consumption unit is 100KV or less, the dual power supply of the power grid is not used for power supply. The user must prepare his or her own generator, but it must be handled in accordance with the provisions of Article 3, Paragraph 1 of these Measures. The self-prepared generator is not allowed to operate in parallel with the power grid. 4. Technical conditions and regulations for dual power supply users. 1. The power distribution room of dual power supply users with a voltage of 10KV and above must be equipped with a dedicated telephone and have an electrician on duty. 2. The backup power supply and main power supply must have reliable safety measures. Such as installing a double-throw switch or an electromagnetic switch with a locking device. A knife switch must be installed on the outside of the electrical lock to provide an obvious disconnect point to prevent mutual transmission of electricity. 3. All 35KV power user substations belong to dispatch (room) dispatching, and the division of their dispatch scope should be clearly stipulated in the dispatch agreement. The 10KV equipment in the 35KV user substation is prohibited from being connected to any external power supply. 4. Normal method for dual power supply users. If one power supply is the main power supply and the other is a backup, which power supply is used in the normal mode shall be subject to the district dispatch regulations. The mode change shall be decided by the district dispatch according to the system conditions, and the dispatcher has the right to decide the operating mode. 5. When the system output is insufficient and users are required to limit power, the Electricity Bureau will only provide security power supply. As above, users are required to separate the capacity and installation address of the security power supply from the working power supply lines to improve power supply reliability. 6. All dual power supply addresses should be equipped with obvious signs, and the dual power signs should be hung with a unified number by the district regulator. A signboard stating "Dual power supplies are not allowed to send power back to the system". 7. For individual users, due to large loads or scattered areas, it is difficult for safe and economical operation when using primary circuit power supply. Dual circuit power supply can be used but internal paralleling is not allowed. 8. Users of dual power supplies should install measuring devices respectively, and units that need to control loads should also install demand meters. 9. Changes in the operation mode of dual power supply users should be implemented only after obtaining the approval of the Electricity Bureau and District Regulatory Commission the day before. When one line loses power, you must first pull the incoming knife gate and switch of the switching line, and then send power to the other line, but report to the ground dispatch immediately afterwards. 10. In order to ensure the safe operation of dual power supply units and power grid personnel and equipment, power consuming units must comply with the requirements of the "Dual Power Supply Electricity License". Anyone who violates the following provisions shall be punished accordingly. (1) Anyone who fails to apply in accordance with these regulations and connects a backup power supply to the power system without obtaining a "permit" will be treated as illegal use of electricity. In addition to removing the backup power supply, a written inspection and corresponding fines will be imposed. If someone is found to have put in a generator privately, their main power supply will be cut off until their own generator is dismantled. (2) Users with dual power supplies are not allowed to transfer power to any unit outside the factory area (including non-important power for the unit) without the approval of the Electricity Bureau. In addition to dismantling it within a time limit, those who transfer it must also be fined for illegal use of electricity. If they refuse to remove or pay the fine, the Electricity Bureau may cancel their backup power supply. (3) If the power-consuming unit does not use dual power supplies in accordance with this method, causing backflow to the system, the power-consuming unit shall bear full responsibility for the accident and compensate for the losses caused by the accident. If the nature of the accident is serious, its legal liability shall be pursued. 5. The power supply department’s management of work after power is available. 1. When the user receives a notice from the Electricity Bureau agreeing to use the backup power supply, he or she can design as required. The design drawings shall be submitted to the Electricity Bureau's Electricity Office for review and approval before materials can be prepared for construction and a completion report will be submitted upon completion. 2. After receiving the completion report, the Electric Power Bureau should organize relevant units to conduct on-site acceptance inspection and issue a "permit" before power can be transmitted. 3. All backup power supplies powered by dual power sources shall be managed by the power station and the rural power station, and shall be inspected and supervised to eliminate unsafe factors and continuously improve the level of safe power consumption. The power bureau also needs to have dedicated personnel to manage dual power users. 6. Business regulations for dual power supply users: According to Article 14 of (78) Dianshengzi Document No. 732, if a user applies for a backup security power supply, it shall be handled in accordance with the following regulations after review and approval by the Electricity Industry Department: 1. Those who do not meet the conditions for industry expansion will be included in the infrastructure projects on their own to build dedicated power supply lines. 2. New users who meet the conditions for business expansion and require high-voltage power supply will be charged a line fee based on the sum of their power supply capacity and spare capacity. New users of low-voltage power supply should pay transformer subsidies based on capacity in addition to line fees. 7. The district regulating office of the Electric Power Bureau should prepare a power supply system diagram and send it to the relevant units. The electricity users should always know the method. 8. If the user requests to change the dual power supply scheme, the application should be re-applied, and the change can only be made after review and approval. Units and individuals within the bureau are not allowed to install dual power supplies for users without permission for any reason. Violators will be held accountable according to the circumstances.

Dual power supplies and dual-circuit high-voltage power supplies can work at the same time and serve as backup for each other. However, in order to operate in parallel, the phase sequence must be the same, and the capacity of the two transformers of the superior power supply should not be greater than 3/1, subject to the technical permission of the superior power supply department.