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Pridružen/-a: 27.09. 2016, 06:54
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 Objavljeno: 03 Nov 2016 04:24 Naslov sporočila: Lightning Proof Transformation of Electrical Equipment in Hi |
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According to China "Building lightning protection design code" GB50057-2010 and "building electronic information system lightning protection technical specifications" GB50343-2004 tunnel electrical equipment should be taken to transform the grounding, equipotential bonding, shielding, rational wiring, installation with Appropriate SPD and other measures to carry out comprehensive protection.
Grounding Modification of Tunnel Electrical Equipment
Road tunnel electrical equipment grounding methods are working ground, protective earth, and lightning protection grounding (such as SPD grounding). Grounding is the basis of lightning protection, grounding system design and construction of a direct impact on the effect of lightning protection. Only a good grounding for the invasion of the lightning current to provide smooth access to the ground release channel, while shielding effect can be guaranteed.
Reconstruction of Monitoring Network of Management Office
When the control room did not use the basis of the bar as a grounding or grounding device grounding resistance can not meet the specifications, you can set up around the monitoring room grounding body, grounding body should be set into a ring. The length of the vertical grounding body is preferably 2.5 m. Its spacing and the spacing of the artificial horizontal grounding body are 5 m. The additional artificial earthing and burying depth shall not be less than 0.5 m, and shall not be less than 1 m away from the external wall or foundation.
Transformation of Tunnel Ground Network
Has been put into operation in the highway tunnel, additional artificial ground within the tunnel is very difficult to spend a lot of manpower and resources, in violation of the principle of economic rationality. (Such as the Zhongshan Jinzishan tunnel, with both sides of the sidewalk inside the cave is equipped with water supply pipes, if the force in the hole with additional artificial grounding need to destroy the water supply pipeline, this method is not desirable). Relatively reliable method is to respectively at both ends of the tunnel soil resistivity is relatively low in the flower bed excavation trench installed artificial grounding body. In order to reduce the grounding resistance, can be used composite grounding, that is, a combination of horizontal and vertical grounding of the grounding body, and fill in the earth around the long salvage resistance agent, and in the tunnel under the sidewalk buried through a tunnel from the diffuse Galvanized steel plate, both ends of the steel plate are connected with the grounding device at both ends of the tunnel.
Equipotential bonding
Equipotential bonding is to separate the metal objects directly connected with a conductor or surge protection connected to the lightning protection device to reduce the potential difference caused by lightning current. The equipotential bonding of the tunnel has two parts, one is the equipotential bonding in the control room, and the other is the equipotential bonding in the tunnel.
Control room electrical equipotential bonding
In the control room to set the ring with the potential to connect the band, control equipment and equipment such as indoor housing and metal structures such as the nearest potential to do a reliable lap. Equipotential bonding belt should be connected with earthing device every 5m.
Connection of Equipotential of Electrical Equipment in Tunnel
Equipotential bonding belts are installed at the appropriate height in the tunnel. Equipotential bonding belts penetrate the whole tunnel, and each equipment in the tunnel is close to the equipotential bonding belt. Equipotential bonding belt should be connected with diffuser galvanized steel plate every 5m.
shield
As lightning is mainly through the electromagnetic induction and electrostatic induction of the tunnel power lines, signal lines and other lines have over-voltage, and along these lines to the impact of the two ends, so that the control room and tunnel electrical equipment was damaged. In order to prevent electromagnetic induction and electrostatic induction on the control room and tunnel electrical equipment damage, should power lines, signal lines and other lines for shielding. The control room and the tunnel between the power lines, signal lines, etc. should be laid in the metal pipe, metal grille or reinforced concrete mixed-grid-type pipe. Metal grid or bar grille from one end to the other end should be conductive through, and should be connected at both ends of the control room and tunnel equipotential bonding zone.
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