SUMMARYThis paper describes methods to monitor partial discharges (PDs) of important power plant components, such as generator stator windings, generator circuit-breaker, and step-up transformer. Two methods have been evaluated under practical conditions, using various sensors: (i) time-domain measurements followed by signal-processing to discriminate between PDs and interference, and (ii) a tunable narrow-bandwidth filter which can be tuned to a frequency where PDs are strong and interference is weak. For several generators, abnormal PD activity was observed. In all cases, the source of these PDs could be located, by means of the transit-time between various sensors. Examples of identified abnormal discharge activity are: (i) discharge activity between phase separations of a statorwinding, (ii) sparking inside a step-up transformer, and (iii) large PDs in a generator circuit-breaker.
This paper describes a method to calculate inductances of magnetic switches, toroidal coils wound on ring‐shaped cores of non‐linear magnetic material. To check the described theory, measurements have been carried out on the inductance of magnetic switches in the saturated state. Most text books give expressions for the inductance, but for the critical applications presented here a better approximation is required. Therefore to calculate the inductance of a toroid, the main and three additional types of flux have been taken into account. As a result of this study, a remarkable agreement between the measured and calculated values is found for a large range of turns. For a toroid with a large number of turns the main flux is large compared to the secondary fluxes. For small numbers of turns however, the main flux and the secondary flux contribute equally to the total flux.
I transm issioñ) *5 ~ F 0* ç T ' C.. 1 " .S 0. 'S .d .1. '. c 01W V •'d .d.'? ' , 5, Soc ' T h is ~~ hnt. i l repoi t deacribes Ilciar measurements and results using th~ U.9-~ Army At~oaph.t L.c R.4.pme.s I,aboratorv ' a 10.6-va l idar and the SRI Mark IX (0.7-u~~ lidar c v c t cc ~i ir lng th~ rlu q t v Infrared Test-I (DIRT-I). The test was conducted at the o'~' 1t e "anda "Issu e Range In October 1978. ç. ' rransmiaalon comparison s are made between the two i.uive l engths with artillery barrages. TNT explos ions , and oil/r ubber firegenerated dust and smoke clouds in a test vane midway (1 km) along the l idar path. A targe t .it the end of the I1d~sr pa th prov ided a reference back s ca tt er re turn for the tranainiqqi"n measurcmenta. Rackacatter properties of the dust and smoke clouds are alan dI ijg~~~d ,
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