1. Generator non synchronous parallel

發(fā)電機(jī)用準(zhǔn)同期法并列時(shí)，應(yīng)滿足電壓、頻率、相位相同這3個(gè)條件，造成并車失敗,如果由于操作不當(dāng)或其它原因，并列時(shí)沒有滿足這3個(gè)條件，發(fā)電機(jī)就會(huì)非同期并列，它可能使發(fā)電機(jī)損壞，并對(duì)系統(tǒng)造成強(qiáng)烈的沖擊，因此應(yīng)注意防止此類故障的發(fā)生。 當(dāng)待并發(fā)電機(jī)與系統(tǒng)的電壓不相同，其間存有電壓差，在并列時(shí)就會(huì)產(chǎn)生一定的沖擊電流。

When the generators are paralleled by quasi synchronous method, the three conditions of the same voltage, frequency and phase shall be met, resulting in the failure of parallel operation. If these three conditions are not met in parallel due to improper operation or other reasons, the generator will be out of synchronization parallel, which may damage the generator and cause strong impact on the system. Therefore, attention should be paid to prevent the occurrence of such faults. When the voltage of the generator to be paralleled is different from that of the system, there is a voltage difference between them, and a certain impulse current will be generated when the generator is paralleled.

一般當(dāng)電壓相差在±10%以內(nèi)時(shí)，沖擊電流不太大，對(duì)發(fā)電機(jī)也沒有什么危險(xiǎn)。如果并列時(shí)電壓相差較多，特別是大容量電機(jī)并列時(shí)，如果其電壓遠(yuǎn)低于系統(tǒng)電壓，那么在并列時(shí)除了產(chǎn)生很大的電流沖擊外，還會(huì)使系統(tǒng)電壓下降，可能使事故擴(kuò)大。一般在并列時(shí)，應(yīng)使待并發(fā)電機(jī)的電壓稍高于系統(tǒng)電壓。

Generally, when the voltage difference is within ± 10%, the impulse current is not too large and there is no danger to the generator. If there are many voltage differences in parallel, especially when large capacity motors are paralleled, if the voltage is far lower than the system voltage, in addition to producing a great current impact, the system voltage will drop and the accident may be expanded. In general, the voltage of the generator to be paralleled should be slightly higher than the system voltage.

如果待并發(fā)電機(jī)電壓與系統(tǒng)電壓的相位不同，并列時(shí)引起的沖擊電流將產(chǎn)生同期力矩，使待并發(fā)電機(jī)立刻牽入同步。如果相位差在±300以內(nèi)時(shí)，產(chǎn)生的沖擊電流和同期力矩不會(huì)造成嚴(yán)重影響。如果相位差很大時(shí)，沖擊電流和同期力矩將很大，可能達(dá)到三相短路電流的2倍，它將使定子線棒和轉(zhuǎn)軸受到一個(gè)很大的沖擊應(yīng)力，可能造成定子端部繞組嚴(yán)重變形，聯(lián)軸器螺栓被剪斷等嚴(yán)重后果。 為防止非同期并列，有些廠在手動(dòng)準(zhǔn)同期裝置中加裝了電壓差檢查裝置和相角閉鎖裝置，以保證在并列時(shí)電差、相角差不超過允許值。

If the phase of the voltage of the generator to be paralleled is different from that of the system voltage, the impulse current caused by the paralleling will produce the synchronous torque, which makes the generator to be synchronized immediately. If the phase difference is within ± 300, the impact current and synchronization torque will not be seriously affected. If the phase difference is very large, the impact current and synchronous torque will be very large, which may be twice of the three-phase short-circuit current. It will make the stator bar and shaft subject to a large impact stress, which may cause serious deformation of the stator end winding and serious consequences such as coupling bolt being cut off. In order to prevent non synchronous parallel operation, some factories have installed voltage difference checking device and phase angle locking device in manual quasi synchronization device to ensure that the electric difference and phase angle difference do not exceed the allowable value when paralleling.

2、發(fā)電機(jī)溫度升高

2. Generator temperature rise

(1)定子線圈溫度和進(jìn)風(fēng)溫度正常，長(zhǎng)期過載,局部線卷有短路,通風(fēng)不暢,而轉(zhuǎn)子溫度異常升高，這時(shí)可能是轉(zhuǎn)子溫度表失靈，應(yīng)作檢查。發(fā)電機(jī)三相負(fù)荷不平衡超過允許值時(shí)，也會(huì)使轉(zhuǎn)子溫度升高，此時(shí)應(yīng)立即降低負(fù)荷，并設(shè)法調(diào)整系統(tǒng)已減少三相負(fù)荷的不平衡度，使轉(zhuǎn)子溫度降到允許范圍之內(nèi)。

(1) The temperature of stator coil and inlet air temperature are normal, long-term overload, short circuit of local coil, poor ventilation, and abnormal rise of rotor temperature. At this time, the rotor thermometer may be out of order, so it should be checked. When the three-phase load unbalance of the generator exceeds the allowable value, the rotor temperature will also rise. At this time, the load should be reduced immediately, and the unbalance degree of the three-phase load reduced by the system should be adjusted to make the rotor temperature fall to the allowable range.

(2)轉(zhuǎn)子溫度和進(jìn)風(fēng)溫度正常，而定子溫度異常升高，可能是定子溫度表失靈。測(cè)量定子溫度用的電阻式測(cè)溫元件的電阻值有時(shí)會(huì)在運(yùn)行中逐步增大，甚至開路，這時(shí)就會(huì)出現(xiàn)某一點(diǎn)溫度突然上升的現(xiàn)象。

(2) The rotor temperature and inlet air temperature are normal, but the stator temperature increases abnormally, which may be the stator thermometer failure. The resistance value of the resistance type temperature measuring element used to measure the stator temperature will increase gradually in operation, or even open circuit. At this time, the temperature suddenly rises at a certain point.

(3)當(dāng)進(jìn)風(fēng)溫度和定子、轉(zhuǎn)子溫度都升高，就可以判定是冷卻水系統(tǒng)發(fā)生了故障，這時(shí)應(yīng)立即檢查空氣冷卻器是否斷水或水壓太低。

(3) When the inlet air temperature and the temperature of stator and rotor increase, it can be judged that the cooling water system is in fault. At this time, it is necessary to check whether the air cooler has water cut-off or the water pressure is too low.

(4)當(dāng)進(jìn)風(fēng)溫度正常而出風(fēng)溫度異常升高，這就表明通風(fēng)系統(tǒng)失靈，這時(shí)必須停機(jī)進(jìn)行檢查。有些發(fā)電機(jī)組通風(fēng)道內(nèi)裝有導(dǎo)流擋板，如因操作不當(dāng)就會(huì)使風(fēng)路受阻，這時(shí)應(yīng)檢查擋板的位置并糾正之。

(4) When the inlet air temperature is normal and the outlet air temperature is abnormally high, it indicates that the ventilation system is out of order. At this time, the machine must be shut down for inspection. Some generating units are equipped with deflector in the ventilation duct. If the air passage is blocked due to improper operation, the position of the baffle should be checked and corrected.