Analysis of street lamp system safety protection From the perspective of the characteristics of street lamp system, this paper puts forward the status quo and problems in the safety protection of street lamp system, and the way to solve the safety protection of street lamp system, mainly short circuit protection, leakage protection and grounding system protection. Short-circuit protection leakage protection circuit breaker grounding method, three street lamp system safety protection measures The whole street lamp system is composed of lighting fixtures and low-voltage power distribution system. If the street lamp system is to operate safely and reliably, its components should be protected by short-circuit protection and matching. Protection of the electrical circuit. The three types of system security protection will be discussed one by one. The lighting fixtures are installed in a harsh outdoor environment, and the safety requirements are higher. Generally, the protection level of the lamps is above IP65, and the diameter of the lead wires in the lamp poles is small, so the lamps need to be single-light short-circuit protection. The selection of the short-circuit protector of the luminaire should ensure that no malfunction occurs under the normal working current and starting current of the luminaire, and when the luminaire is short-circuited, it should be reliably operated, and the cut-off time should be verified according to the fault short-circuit current. In the actual project, 250W, 400W high-efficiency energy-saving high-pressure sodium lamps are commonly used, and the working current of each street lamp is as follows. First set the parameters of the lighting fixture, the ballast loss is 10%, the power factor is 0.85, and the inner lead of the lamp post is BVVB-2X2.5 sheathed wire. The working current is: from the above data: 250W, 400W high-efficiency energy-saving high-pressure sodium lamp can choose 10A short circuit protector. To ensure the safety of the street lamp system, only the short-circuit protection of the lamp is not enough. The protection of the distribution circuit is also very important in the special case of the street lamp. For most of today's streetlight systems, only the overload protection and the leakage protection in the special box change are considered to be due to the poor laying conditions of the street lamp system and the relatively humid environment. This may cause the leakage protection circuit breaker to malfunction and reduce the continuous operation of the system. Sex. As a kind of safety protection device, the leakage protection circuit breaker can protect the personal safety when a single-phase earth fault occurs, effectively preventing personal electric shock. Indirect contact shock protection (ie protection against accidents caused by electrified electrical lines and equipment enclosures in the event of normal unpowered faults) in accordance with the Low Voltage Power Distribution Design Specification in conjunction with the International Electrotechnical Commission Standard (IEC479-1) Strict regulations have been made. The specification stipulates that the normal electric shock safety voltage limit of normal environment is 50 volts. The ground fault protection of the distribution line shall not be more than 5 seconds for the fault circuit to be cut off. Obviously, it is difficult to meet the above requirements without a leakage protection circuit breaker, and only a leakage protection circuit breaker is possible. The following data is used to verify the role of the leakage protection circuit breaker in the actual project, and the rated leakage current (iAn) of the leakage protection circuit breaker is set to 200 mA. The design requires the distribution circuit grounding resistance Rd to be 10 ohms, then the contact voltage = RdXIAn =10X0.2=2V, within the specified allowable safe voltage range. The use of leakage protection circuit breaker can also prevent the cable from overheating due to the long-term leakage current, thus affecting its service life and the possibility of electric arc leakage current damage to electrical equipment. Then, if the leakage protection circuit breaker is used in the street lamp system, it should be installed in the main trunk or the distribution circuit. Personally, it should be installed on the distribution circuits of the special box. Because the normal leakage current on the main trunk line is the sum of the distribution circuits, once the fault occurs, the leakage protection circuit breaker is protected, and other circuits that have not failed can not work normally. In the actual project, the rated leakage current (IAn) of the leakage protection circuit breaker is generally worth much. The specification requirement (IAn) is greater than 1.3 times the maximum phase load current and the sensitivity of the leakage protection circuit breaker is checked. The leakage protection circuit breaker is related to factors such as preventing electrical fire, eliminating arc current, limiting contact voltage, and whether the street lamp system can continue to operate. Generally, (IAn) can take 100mA, 200mA, and the ground environment can be adjusted to be high, but the maximum should not exceed the street lamp low voltage. The characteristics of the power distribution system are: first, the total load of each distribution circuit is not large but relatively scattered; second, the distribution circuit is relatively long, usually 5001000m; third, the contact rate with maintenance personnel and pedestrians is relatively high. Therefore, choosing the grounding method of the street lamp low-voltage distribution system is also the top priority of the street lamp system. In actual engineering, the TN-S system and the TT system are usually used. First, the characteristics of the two grounding methods are briefly stated. TN-S system: This system has higher safety. However, due to the long distribution circuit of the street lamp system, if there is a leakage fault in the case of PE line interruption in the line laying, the circuit breaker cannot be cut off, and the electric shock may be caused. H system: Every base lamp is grounded. When the phase line of the street lamp is in contact with the lamp post or the lamp is damaged and the electric leakage causes the lamp post to be charged, the street lamp has grounding protection, which can greatly reduce the risk of electric shock. However, the relatively low leakage current of the H system may cause the low-voltage circuit breaker not to trip, causing the pole-to-ground voltage to be higher than the safe voltage. Therefore, the TT system can install a leakage protection circuit breaker for each distribution circuit. In combination with the advantages and disadvantages of the above grounding system, in the actual project, two systems can be adopted to combine the lengthening and complementing methods. The local TT system is used under the TN-S system, and the protective grounding of the TT system is performed within a certain distance. The grounding body is grounded. Module or ground. A grounding pole is made every 180200m along each distribution circuit. The galvanized flat steel is connected with two adjacent light poles to form a grounding grid. The light pole is reliably connected with the PE line of the distribution trunk to ensure the special box is changed. The grounding resistance is not more than 4 ohms, and the grounding resistance in each circuit is not more than 10 ohms. This kind of combination has been adopted in the actual design project, which not only reduces the construction cost, but also improves the safety of the system. Second, the conclusion Street lamp system is a necessity for urban construction and development, and is closely related to our daily life. Therefore, the safety of the street lamp system is particularly important. The improvement of its safety protection measures can make the whole system operate safely and reliably, so that it can serve the public more effectively and protect the safety of the people. Only in this way can the street lamp system become an important guarantee for the normal operation of urban road traffic, a sign of the cultural and economic development of the city. 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September 20, 2023