Nanjing NARI NSR6320 capacitor protection device
1 AC flow collection
The device can collect Ua Ub、Uc、3I0、Ia、Ib、Ic。 AC sampling method is adopted for voltage, current and other electrical quantities. 40 points are sampled every week. Fourier algorithm is adopted for calculation of electrical quantities. After sampling and calculation, the device outputs the effective values of each voltage, current and three line voltages, and calculates the active power, reactive power, power factor, frequency and other parameters. The accuracy of voltage and current is 0.2%, power accuracy is 0.5%, and frequency accuracy is better than 0.003Hz.
2 Switching value acquisition
The switching value signal collected by the substation measurement and control device, namely the remote signal quantity called by telecontrol, reflects the operation status of the substation primary equipment, the action signal of the control equipment, the alarm signal and other information. The dispatcher uses this as the basis to determine the equipment working condition and decide whether to operate. The correctness of its information directly affects the operation mode of the system, the correct action of the automation equipment and the decision of the dispatcher, which is of great significance to the normal operation of the power grid.
The principle of the remote signal acquisition by the measurement and control device is that the hardware first performs photoelectric isolation transformation on the signal input, converts the strong current on-off signal to the "0" and "1" levels of the digital quantity, and then conducts timing sampling processing. When the remote signal changes, the measurement and control device records and marks the time mark to form a Sequence of Events (SOE).
The switching value signal jitters due to site node signal jitter or electromagnetic interference. In order to prevent false alarm or missing alarm of remote signaling, the device filters the remote signaling signal by hardware on the one hand, and by software on the other hand. The software filtering scheme is shown in Figure 4.1. The device specially designs a fixed value Td of remote signal debounce time for each remote signal, which means that the relay contact has a long jitter time. When the signal jitter time Δ t is less than the parameter Td, the signal will return to the previous stable state after jitter, which is determined to be affected by electromagnetic interference, and the jitter is filtered out, as shown in Figure 4.1a. When the signal jitters, record the current time. If the signal jitters for Δ t time and then reaches a stable state, and the stable time is greater than Td, it can be confirmed that the signal has shifted, as shown in Figure 4.1b
Nanjing NARI NSR6320 capacitor protection device
1 Introduction to five prevention functions
The device has the monitoring integrated five prevention function, and there are three working modes, namely "monitoring five prevention", "interval five prevention", and "five prevention unlocking". It can be switched by switching the "three station" handle on the interval measurement and control cabinet. The device collects the remote signal values of the "monitoring/five prevention" and "five prevention unlocking" configurations in the "remote signal configuration" to determine the current mode. When the "five prevention input" control word is 1, when the "unlock mode" input is 1, regardless of the "monitoring/interval mode" input, the device is in the five prevention unlock mode; When the "unlock mode" position input is 0, the device is in monitoring mode or five prevention mode according to the "monitoring/interval mode" position input. When "Five prevention input" is 0, the default is unlocking mode.
1. Monitoring five prevention mode
The device receives the remote unlocking/locking command from the background/master control to the locking node. Under normal conditions, the output of the locked node is not allowed, and the node remains open; When receiving the remote unlocking command (remote closing of five prevention nodes), start the rule judgment, continuously judge the rule conditions within the extended pulse width time, and control the output according to the logic operation results. When the extended pulse width time is exceeded or the remote control locking command (five prevention node remote control opening) is received, the locking node will be opened immediately if the rule is not judged generally. After the background unlocking command is judged by the rules of the startup device, the command can be automatically reset after a delay to prevent the background from missing the locking command, and the locking node will be unlocked for a long time.
2. Interval five prevention mode
The device does not receive the remote unlocking/locking command from the background/master control to the locking node. According to the object configuration rules and conditions, the device automatically judges the condition control output, that is, only judge whether the five prevention rules installed to the device are met, and if they are met, the "five prevention remote unlocking remote signaling" output is 1.
3. Five prevention unlocking mode
The device does not receive the remote unlocking/locking command from the background/master control to the locking node, does not judge the object rule conditions, and normally keeps the locking node closed.
