Power System Protection And Switchgear By Badri Ram Dn Vishwakarma Pdf 44
a current protection relay is used to measure a current flowing in a circuit and shut the circuit off when the current exceeds a predetermined level. a voltage protection relay is used to measure a voltage and shut the circuit off when the voltage exceeds a predetermined level. a frequency protection relay is used to measure a frequency and shut the circuit off when the frequency exceeds a predetermined level. a sequencing relay is used to measure a current and to compare it with a predetermined setting and open the circuit if the current is below the predetermined setting. a protection relay may be a current, voltage, or frequency protection relay. each type of protection relay can be programmed to perform several different functions.  :ch 7, p 52. a protection relay is used to measure a voltage and to shut the circuit off when the voltage exceeds a predetermined level.
the current transformer consists of a wire, called a "ring", wrapped around a magnetic core. the ring is made from a number of layers of wire which are wound about the core. the length of the ring is related to the sensitivity of the current transformer. current transformers can therefore be made sensitive or insensitive by increasing or decreasing the number of layers in the ring. current transformers are typically used in power systems to measure and detect current, voltages, and power; and to measure and monitor load (the amount of power consumed by a load).
the opening and closing of the contacts is usually timed by a mechanical relay, which is termed a contactor. such relays employ powerful solenoids or electro-magnetism to control power contactor contacts. an electromechanical relay is a device that permits the operation of a load circuit by the application of power to a fixed contact in the power circuit. the current in the power circuit is measured, and the contactor is set to trip when the current exceeds a preset limit. the relay is mechanical in construction and employs a spring to tension the contacts and force them into engagement. the relay has a solenoid coil and armature, which are housed in a case or chamber and is energized by applying a current through the coil. a spring holds the contacts closed, but when the solenoid armature is energized, the contacts are released. a relay's contacts may be of the push-pull or pull-push type. a single pole single throw switch is a mechanical relay that incorporates a single contact, which is normally closed but may be opened by an external force. push-pull and pull-push single pole single throw switches are used with electric power in order to control the output of electrical apparatus. a single pole double throw switch is a mechanical relay that incorporates two contacts, one normally closed and the other normally open. when the switch is activated, either of the two contacts is open and both are closed. the single pole double throw switch is used to control the output of electrical equipment. two pole two throw relay is used to control more than one contact at a time, for example, to open and close different circuits on different days. the coil has multiple windings and contacts that are installed on the interior of the coil and energised by alternating current. 81555fee3f
clc workshop on power electronics 2013. pdf
power system protection and switchgear by badri ram dn vishwakarma pdf 44A preservative effect on the rabbit small intestinal mucosa following a single high dose of carrageenan.
Carrageenan, a sulphated polysaccharide from red seaweed, induces acute and chronic inflammation in the intestine and ascites in rats. This study was designed to evaluate the effects of a single high dose of carrageenan (100 mg/kg body weight) given to male Wistar rats and a single high dose (250 mg/kg body weight) given to male New Zealand rabbits on the intestinal mucosa. Five days after the high dose given to rats, the mucosal acid phosphatase (ACP) activity decreased significantly in the jejunum but not in the ileum. In rabbits, the intestinal total mucosal ACP activity decreased significantly in the jejunum at 1 day. The decreased mucosal ACP activities were recovered to control level at 7 days in both rats and rabbits. Histologically, in the rats, the submucosal and the lamina propria in the jejunum showed moderate to severe lymphocyte infiltration, but no degeneration of the villus-crypt unit. In the rabbits, the submucosal and the lamina propria in the jejunum showed mild infiltration of lymphocytes but no degeneration of the villus-crypt unit. The results suggest that following a single high dose of carrageenan, the mucosal ACP activity is decreased in the rat jejunum. It is not a dose-dependent response. The decreased mucosal ACP activity may be partly due to a direct cytotoxic effect and partly due to a decrease in the quantity of bile salts produced by a decrease in the rate of sodium taurocholate reabsorption. In the rabbit, a single high dose of carrageenan, given to young adult rabbits, had no effect on the intestinal mucosa.
It has been reported that the rate of post-traumatic stress disorder (PTSD) in combat zone veterans is six times higher than the rate in the general population (Cardinal et al. [@CR16]). In addition, in a sample of combat veterans and civilians, the ACE score was significantly higher in combat veterans (Bradley et al. [@CR11]). The higher ACE score in combat veterans could be explained by higher levels of