XW-PLB type generator comprehensive protector
XW-PLB type generator comprehensive protector
1 Overview
In traditional power station protection systems, relay-type protection devices are often used for generator overcurrent and overvoltage protection. Such devices generally have the disadvantages of low accuracy, poor stability and reliability, and cumbersome installation.
Yongyuan brand XW-PLB generator integrated protector is an intelligent control and protection device specially designed for the problems of relay protection. It uses an eight-bit microprocessor as the core and uses precise control algorithms to make the device have excellent control performance and control accuracy.
This device has overload, over current, short circuit inverse time current protection and over voltage, under voltage, over speed, under speed, and runaway protection in one. Over-speed and under-speed protection will automatically deal with differently according to the grid connection of the generator (current>6%Ie is regarded as grid connection status). It can completely replace the traditional protection mode of multiple relays, simplifying the installation process and improving reliability. The device can display the generator voltage, current, and frequency values in real time, which is easy to observe and operate. It is very convenient to use and can be applied to the transformation of small and medium power stations and old power stations. It can greatly improve the reliability and safety of generator protection, and it is also of positive significance for improving the automation level of power stations.
2. Technical indicators
2.1. Scope of application: various medium and small high-voltage and low-voltage generator sets; motor and line protection
2.2. Input signal:
2.2.1. PT voltage: Nominal 100V generator PT voltage transformer voltage
2.2.2. Nominal 230V generator phase voltage
2.2.3. Nominal 400V generator line voltage
2.2.4. Three-phase current: nominal 5A generator three-phase CT (current transformer) current signal
2.3. Output signal:
Relay switch signal (normally open mode)
Relay contact capacity: AC 220V/5A, 380V/2A
DC 110V/0.8A 220V/0.2A
2.3.1. Fault output is used to disconnect the grid-connected switch
2.3.2. Speed protection output is used to control speed governor deceleration or water bypass
2.4. Voltage measurement accuracy: not less than ±1%
2.5. Current measurement accuracy: not less than ±1%
2.6 Frequency measurement accuracy: not less than ±0.01%
2.7. Power consumption: less than 6W
2.8. Power supply
AC 150VAC~285VAC DC 100VDC-300VDC
2.9. Working environment
Ambient temperature -5°~+45°
Relative humidity is not more than 90%
Areas below 2000 meters above sea level
2.10. Installation dimensions
112mm in length × 112mm in width × 108mm in depth
11. Hole size (see figure 6) 114mm × 114mm
3. Main functions
3.1. Overvoltage protection
During system operation, when the generator voltage is continuously higher than the set overvoltage protection value for a certain period of time (this time can be set), the protector is judged as an overvoltage fault, and the protector will issue a regular'trip' command regardless of whether it is connected to the grid ( The conventional'trip' command is: the'fault' relay and the'flying car' relay act at the same time. After 10 seconds, if the generator frequency is measured to be ≤52HZ, the relay will be released) for the'trip' (when connected to the grid) and the governor Decelerate, and at the same time send out regular alarm signals (intermittent buzzer alarm sound, fault indicator light), the digital display automatically switches to the voltage value display state, the current voltage value is displayed in real time, and the voltage indicator light flashes. After the normal alarm signal is delayed for a set period of time, if the generator voltage returns to normal, the alarm signal will be released and the fault state will be exited.
Note: Any failure state can be manually exited in advance. Press the 'parameter' key for a few seconds to exit the failure state. Use the 'increase' and 'decrease' keys to cancel the buzzer alarm, but you cannot exit the fault state in advance.
3.2. Undervoltage protection
When the generator voltage is continuously lower than the set under-voltage protection value, the protector is judged as under-voltage state. Before grid connection, the fault relay does not operate, but it sends out a regular alarm signal. When there is no other fault, the digital display automatically switches to the voltage value display state, and the voltage indicator flashes. After the generator voltage is normal, it will automatically exit the fault state. After connecting to the grid, if parameter 01 is selected as undervoltage and need to trip (LUYY), then undervoltage will be handled like overvoltage, and normal 'trip' command and normal alarm signal will be sent to enter the fault state. In addition, the under-voltage protection can be turned off. When the under-voltage setting is lower than 50% (49%) of the rated voltage, this function will be turned off.
3.3, overload protection
In grid-connected operation, the largest one of the three-phase currents of the generator is continuously greater than the overload setting value
(102%~110%Ie) When a certain time (this time is relatively long and can be set), the protector is judged as an overload fault. Overload fault and overcurrent fault processing are not the same. When parameter 02 is selected as overload and need trip (LLYY), they are very similar. For the treatment method, refer to the next section Overcurrent fault processing; but when parameter 02 is selected as overload without trip (LLnO) They are different. At this time, the overload only sends a regular alarm signal, and the fault state can be manually exited early. The protector has an inverse time control function. Set the ratio of the difference between the measured current minus the overload setting value and the one-hundredth of the rated current (1% Ie) to N, the overload setting time is Tas, then the actual overload time Ta is: Ta =Tas/(1+N/50). The overload time Ta timing is cumulative, and interruption is allowed in the middle of timing, but when the maximum one-phase current is less than 90% Ie, the timing will decrease until it is reduced to 0 (for every 1% Ie of the current, the decrease rate of Ta timing is the standard timing 1/50, that is, if the maximum one-phase current is 40% Ie, the overload timing will be reduced to 0 in the same time).
3.4, overcurrent protection
In grid-connected operation, the largest one of the three-phase currents of the generator is continuously greater than the set overcurrent setting value
(110%~150%Ie) When a certain period of time (this time can be set), the protector judges an over-current fault and sends a regular "trip" command and a regular alarm signal. The digital display automatically switches to the current value display state, displaying the current value at the moment of tripping, and the current indicator light flashes. After a set delay time, the alarm signal will be automatically released and the fault state will be exited. You can also exit the fault state manually in advance. Overcurrent protection is also inverse time limit control. Based on the set overcurrent delay trip time, the protector automatically modifies the overcurrent action time according to the principle of "equal temperature rise". The greater the overcurrent, the faster the protection action. Overload protection and overcurrent protection are carried out at the same time. When the actual current is greater than the overcurrent setting value, the overcurrent timer
Start, but the overload timing will continue without interruption. Whoever reaches the set value first will act first.
The calculation method is as follows: Suppose the ratio of the difference between the measured current minus the overcurrent setting value and the one-hundredth of the rated current (1%Ie) is N, the overcurrent setting time is Tbs, then the actual overcurrent time Tb is: Tb= Tbs/(1+N/40). The over-current time Tb timing is also cumulative, and interruption is allowed in the timing, but when the maximum one-phase current is less than 75% Ie, the timing will decrease until it is reduced to 0 (for every 1% Ie of the current, the Tb timing decrease rate is the standard timing 1/40).
3.5, short circuit protection
When the maximum one-phase current of the generator's three-phase current reaches the short-circuit setting value (1.8~3.0Ie), the protector is judged as a short-circuit fault, and the fault relay acts immediately. Other treatments are similar to over-current faults. Note that the current display value is the current value before the trip.
3.6, low speed protection
The low-speed protection is divided into "grid-connected" and "grid-connected". Before "grid-connected", when the generator speed is reduced from the normal state to below 35HZ, the protector is judged to be in the "low-speed" state (the low-speed state when it is just turned on is not meeting). The protector "flying car" relay operates (the "fault" relay does not operate), and the "normally closed" combination of the "fault" relay can be used as low-speed protection of the generator (usually used to hold the shaft to solve the low-speed bearing oil film problem), see As shown in the figure below, a regular alarm signal is issued at the same time, and the general digital display will automatically switch to the frequency display state, and the frequency indicator will flash. This function can be turned off by parameter 03. When the low-speed protection is closed, the "water-folding" (water bypass or valve closing) signal can be directly controlled by the "flying car" output, and the connection shown in Figure 2 is no longer required. After "grid-connected", in some small power grids, the generator speed may be unstable. When the generator speed is lower than the low speed setting value (46.5HZ~49.5HZ), the protector judges a "low speed" fault and sends a regular "trip" Commands and general warning signals. In addition to "tripping" to cut off the generator output, it also combines a "deceleration" signal to control the speed governor to decelerate (or "water bypass"). Although it is a "low speed" fault, generally speaking, it should not be decelerated again, but the generator will inevitably increase speed after "tripping", so it should still be decelerated. After 10s, check the generator speed after "tripping" if it is less than 52HZ, then exit "Low speed" fault state. The low-speed protection function can be manually selected to remove 46.5HZ (because there is almost no power grid with a frequency as low as 46.5HZ).
3.7. Overspeed (speeding) protection
Over-speed (speeding) protection is also divided into "before grid connection" and after "grid connection". Over speed before "grid connection" is usually called "flying vehicle". After system load rejection and protection tripping, the turbine has no time to close the water valve and generate electricity The machine may experience speeding. When the protector confirms that the generator frequency (speed) exceeds the set value (55.0HZ~75.0HZ), it will be judged as a "flying car" fault.
The "fault" relay and the "flying car" relay act at the same time, and a "deceleration" signal is combined to control the deceleration (or "water bypass") of the speed governor. At the same time, a regular alarm signal is issued. The general digital display will automatically switch to the frequency display state. The indicator light flashes. After 10 seconds, if the generator speed is less than 52HZ, it will exit the "overspeed" fault state. After "grid-connected", in some small power grids, the generator speed may be unstable. When the generator speed is greater than the over-speed set value (50.5HZ~53.5HZ), the protector judges an "over-speed" fault and sends a normal " "Trip" command and general alarm signal. Other handling of the fault is the same as the handling of "low speed" after "grid connection". The over-speed protection function can also be manually selected to remove 53.5HZ (because the power grid with a frequency as high as 53.5HZ almost does not exist)
3.8. Voltage input line dropped
When the voltage input line is disconnected or the generator voltage is zero, it is judged as a "disconnected" fault, the fault relay does not operate, but a regular alarm signal is issued. When there is no other fault, the digital display automatically switches to the frequency display state. Both voltage and frequency display are 0000. When the voltage input is normal, it will automatically exit the fault state.
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