Stator Cooling Water System Instrumentation

Author(s):  
Thomas Bauer ◽  
Mat Svoboda ◽  
Russell J. Chetwynd

Large turbo- and hydro-generators are directly cooled with high purity water for efficient heat transfer from the coils. Plant operators, engineers and chemists don’t get a lot of experience with troubleshooting, as operation can be trouble free for decades. However, when a problem arises, it can happen rapidly. The reason is often plugging of the stator cooling water system (SCWS) copper hollow conductors. This can result in forced outages or major generator failures and can occur within weeks — or years — after first indication. Thus, proper instrumentation will support plants to early detect a malfunctioning cooling water system and can provide sufficient time to take effective corrective actions. The focus is on how both the SCWS and its internal instrumentation, along with enhanced monitoring techniques, can help facilitate a more proactive approach to manage corrosion effects such as hollow conductor plugging. Different basic OEM supplied instrumentation for both high- and low-oxygen systems are discussed and benefits thereof are outlined as well as “state-of-the-art” instrumentation is presented. Industry examples are demonstrating the benefit of proper instrumentation as early detection of copper oxide plugging prevented power plants from forced outages and costly rewinds. Subsequently, full cooling capacity was restored by online removal of the copper oxides.

2013 ◽  
Vol 732-733 ◽  
pp. 382-386
Author(s):  
Ni Zhang Xiao ◽  
Nan Zhang Xiao ◽  
Long Wu Wen ◽  
Rui Ju Zhao ◽  
Chun Lei Zhang

The effects of anti-scale, anti-corrosion and disinfection of circulating cooling water with electro-magnetic treatment and chemical treatment in the laboratory are compared. The applications of electro-magnetic treatment in power plants are summarized and discussed. The results of both experiments and applications in power plants show that the electro-magnetic treatment can be used in particular conditions, but the development of electro-magnetic treatment technology is immature. This technology used in circulating cooling water system in power plants should be further proved by more experiments and field applications.


Author(s):  
Liang Zhang ◽  
Gang Xu ◽  
Yue Wang ◽  
Li Chen ◽  
Shao Chong Zhou

Abstract Safety-related items in nuclear power plants are now generally placed separately from the non-safety-related items, but it was not strictly required before. Therefore, it is very important to study whether the non-safety-related items will affect the safety-related items when they are dropped down in an earthquake situation, which determines the safety of a nuclear power plant and its future life extension applications. This research was based on the cooling water system room with the safety and non-safety related items installed together, as an example to study whether the non-safety-related items such as vent pipes and DN50 fire fighting pipes arranged above will damage the DN300 pipes and valves arranged below when earthquakes occur. For the experiments, the relative positions of objects in the room was reproduced by 1: 1. The pressure-holding performance of the pipe was used as a criterion for the damage. The research results of the experiments show that when the 10-meter-long DN50 pipe was dropped from the position of 8 meters height and the 8-meter-long vent dropped from position of 3.6 meters height, they do not affect the integrity of the DN300 valve and pipe below. After the experiment, pressure drop in two hours for the pipe is less than 0.1%. The main body of the valve does not fail neither. The numerical simulation study also shows that there is no failure phenomenon in the simulation as well. Compared with the test results, the impact acceleration and the vent deformation both have the same trend.


Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1592 ◽  
Author(s):  
Ziqiang Lv ◽  
Jiuju Cai ◽  
Wenqiang Sun ◽  
Lianyong Wang

Open circulating cooling water system is widely used in process industry. For a system with a fixed structure, the water consumption and blowdown usually change with the varying parameters such as quality and temperature. With the purpose of water saving, it is very important to optimize the operation strategy of water systems. Considering the factors including evaporation, leakage, blowdown and heat transfer, the mass and energy conservation equations of water system are established. On this basis, the quality and temperature models of makeup and blowdown water are, respectively, developed. The water consumption and discharge profiles and the optimal operating strategy of the open recirculating cooling water system under different conditions are obtained. The concept of cycles of temperature is proposed to evaluate the temperature relationship of various parts of the open circulating cooling water system. A mathematical relationship is established to analyze the influence of the water temperature on the makeup water rate of the system under the condition of insufficient cooling capacity of the cooling tower. In addition, the co-influences of quality and temperature parameters on the system are analyzed.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xu Ping ◽  
Wang Jing ◽  
Zhang Yajun ◽  
Wang Jie ◽  
Si Shuai

Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water.


2015 ◽  
Vol 93 ◽  
pp. 293-300 ◽  
Author(s):  
Fang Liu ◽  
Li Zhang ◽  
Xi Yan ◽  
Xianhui Lu ◽  
Ya Gao ◽  
...  

2014 ◽  
Vol 24 (2) ◽  
pp. 848-858 ◽  
Author(s):  
Nihal Doğruöz Güngör ◽  
Ayşın Çotuk ◽  
Esra Ilhan-Sungur ◽  
Nurhan Cansever

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