What Is a Network Protector?
The network protection device is a special heavy duty electrically operated air circuit breaker controlled by a network relay. When power flows from the low voltage bus to the transformer, the circuit breaker automatically trips. When the voltage in the system causes power to flow from the transformer to the low-voltage bus, the circuit breaker will close automatically. [1]
- The network protection device is a special heavy duty electrically operated air circuit breaker controlled by a network relay. When power flows from the low voltage bus to the transformer, the circuit breaker automatically trips. When the voltage in the system causes power to flow from the transformer to the low-voltage bus, the circuit breaker will close automatically.
- Network protection devices are usually equipped with protective relays. The protective relays only act when the network transformer or a voltage feeder fails. Such networks often operate under the assumption that faults will blow out.
- Network protection devices without auxiliary protection do not meet the requirements of ANSI / NFPA 70-198112 for overcurrent, ground fault or short circuit protection. If the network protection device is self-equipped by the user and used as a power disconnect device, sensors including ground detection can be added to trip the network protection device to protect the network and the busbar. [1]
- Take the low-voltage power supply as an example. In this power supply method, the low-voltage mains are connected into a grid.
Network protection device network protection device
- The present invention relates to a network protection device (110) for controlling communication between an external data processing device (200) outside an automation network (100) and an automation device (190) in the automation network (100). An automation protocol is provided in communication with the automation device (190), and a protocol rule is stored or capable of being stored in the network protection device (110), which includes a predetermined value that enables the transmission or non-transmission of the automation protocol The decision of the protocol message depends on the content of the protocol message, and-wherein the network protection device (110) is also designed to make a decision on the transmission of the protocol message with or without the input of the automation protocol, where the input protocol message corresponds to the protocol rules Predetermined value. [4]
EPON Network protection device An EPON network protection device and method
- The invention provides an EPON network protection method. The method is applied to an OLT device having first and second PON ports. The first PON port is connected to the first optical splitter, and the second PON port is connected to the last optical splitter. The optical splitters are connected in order to form an EOPN network whose trunk optical path is circular. Initially, the first PON port is in the working state and the second PON port is in the listening state. The protection method includes the following steps: listening to the optical signal with a wavelength of 1490 nm at the second PON port; if the wavelength is not received within a predetermined time Optical signal to switch the state of the second PON port to a working state, so as to allow downlink data to be sent from the second PON port and to receive uplink data sent by the ONU device. The invention realizes the protection of the trunk optical path failure of the EPON network at a lower cost and is compatible with the existing ONU equipment. [5]