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With decarburization of the electrical grid, the penetration of renewable energy generators (REGs) is increasing. Consequently, the operating environment of the electrical grid is greatly altered and the existing protection system for the electrical grid cannot adapt to the new environment. In order to solve the existing protection problems, the equivalent model for calculating short-circuit current of the REGs should be built. The calculation model depends on the fault current characteristics of REGs that are different from the conventional generators (synchronous generators). The short-circuit current characteristics of REGs are related with the corresponding inverter control strategies. However, the strategies are diverse from manufacturer to manufacturer and are unknown to the public. As a result, it becomes difficult to reveal the fault current characteristics and realize fault current calculation without knowing the control strategies. In this paper, the focus is on the fault current characteristics and their calculation models of inverter-interfaced REGs (IIREGs). To reveal the relationship between the inverter's control strategies and the IIREG's short-circuit current characteristics, a coordinated control strategy for gird-tie inverter and DC-link chopper is proposed. The main factors affecting the transient and steady-state shortcircuit currents are analyzed and revealed for IIREGs. Further, the calculation model of the steady-state short-circuit current from IIREGs is established, which is independent of the specific inverter's control strategies. Finally, based on the experimental test bench, both the fault ride through (FRT) capability and short-circuit current model of IIREG are verified. The results can be used for assessing and improving the relay protection strategies of the electrical grid with lots of IIREGs. [ABSTRACT FROM AUTHOR]

This study proposes a new fault impedance estimation algorithm of phase-ground fault for ground distance relaying based on the negative-, zero- and comprehensive negative–zero-sequence current component. The principle is based on the assumption that fault path is purely resistive, and the phase angle of fault point voltage and fault path current is equal to construct the fault impedance estimating equations for ground distance relay, which can eliminate the effect of fault path resistance, load current and power swing. PSCAD software simulations show the accuracy of proposed algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes a decentralized model for dc load flow based congestion management for the forward markets via Optimal Resource Allocation (ORA). The available thermal capacities of possible congested transmission lines are considered as commonly shared resources for all bilateral and multilateral transactions in the market. In our model, each transaction maximizes its profit under the limits of transmission line capacities allocated by the ISO. The ISO searches the optimal allocation of line capacities to each transaction. Finally, the same market efficiency (social welfare) as centralized optimization can be reached. The ORA-based decentralized approach is more suitable for power market environment, since it always keeps the intermediate solution feasible during the iterations and does not require each transaction to submit their private and sensitive information. The mathematical model, computation procedure and relevant proof are presented. The computer test results from the IEEE 30 bus system illustrate the effectiveness of proposed approach. [ABSTRACT FROM AUTHOR]

In order to accurately measure the impedance, the residual current for impedance measurement in ground distance relay is compensated in a fixed manner. It has been shown that the above compensation manner may have negative impact on the phase selection in mho elements in a single-pole trip scheme. A new residual current compensation method based on the magnitude of current of each phase for mho elements is presented in this paper. The performance of this new method is analyzed under all kinds of fault conditions. Simulation studies are carried out to investigate the new compensation method based fault component impedance relay in a typical transmission system. The relay has shown satisfactory performances under various fault conditions especially for the close-in ground fault and cross-country fault. This new compensation method can also be used in phase selector based on impedance measurement. [ABSTRACT FROM PUBLISHER]

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Objective: Detect the hearing deficiencies of the candi­da­tes of the gendarmerie’s competition., Material and Method: Pros­pec­tive study realized over 3 years (2008-2010), in the ENT service of the Gendarmerie to Agban (Abidjan). Examination included an otoscopy and a pure tone audiometry., Results: On 23121 candidates, 1245 had a plug of earwax (5.4%). They were aged from 18 to 25 years old (average age: 22.85 years). Eardrum was pathological in 0.5 % of the cases. Prevalence of hearing loss was 1.5%. Hearing loss included sensorineural hearing loss (56.7%), deafness of transmission (29.4%) and mixed deafness (13.9%). Deafness was unilateral in 79.8% and bilateral in 20.2%., Conclusion: Result of audio­gram will be useful for tracking or assessing cases of noise-induced hearing loss attributable to military service.

Introduction: Dermoid cysts of the submandibular region are rare. We report an exceptional case with extension to the neck., Observation: The patient presented with a voluminous left submandibular cystic tumor with extension to the neck and to floor of the mouth. Ultrasonography and CT scan contributed to the diagnosis and to chose the best surgical approach in case of large cyst. In our case, the tumor was removed using a double cervical and intraoral approach. Histopathological examination confirmed a dermoid cyst., Discussion: We report an exceptional case of dermoid cyst originating from submandibular region. A double surgical approach was necessary for tumor resection. Tumor removal must be complete; the submandibular gland may be removed if necessary., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Objectives: To appreciate the value of a simple radiographic incidence and its effectiveness for the search and the measurement of elongated styloid apophysis (ESA) and to recommend it in the routine search of ESA in practice., Patients and Method: This prospective study was realized over a period of 3 years. It involved the study of ESA from conventional radiographic imaging; the face low incidence in comparison with an experimental incidence, the oblique profile chin lift (OPCL). 101 patients presenting with stylalgia were investigated., Results: Out of the 101 patients, the low face cliché found 49 ESA having an average length of 5 cm. The OPCL allowed to identify 63 ESA, 54 of which were bilateral and 9 unilateral. It also helped identify other associated abnormalities: otitis media (5 cases), dental pathologies (4 cases), dental condensing osteitis (2 cases). The comparative analysis demonstrated a better efficiency of the OPCL in comparison to the standard incidence: the LOW FACE (Roc curve). The OPCL allowed the exposure in one incidence the styloid process and to better appreciate the lower and superior borders of the styloid process giving a better estimate of its measurements., Conclusion: It appears from this study that the experimental incidence, the OPCL presents a real interest in the investigation of the ESA but also in the study of the soft tissues of the pharynx, the cervical spine, and the temporo-mastoid region. It also allows the detection of other.

Introduction: Nasal NK/T cell lymphoma is an aggressive, locally destructive and necrotizing lesions. It is exceptional rare in Africa., Case Report: We report a 73 year-old patient's case presenting a nasal obstruction with a chronic purulent nasal discharge. The physical examination showed a chronic nasal lesion involving the nose and infiltrating the pyramid. The histopathological examination performed in a french laboratory diagnosed a nasal T cell lymphoma. Chemotherapy was initiated; radiotherapy being unavailable., Conclusion: The difficulties in management of nasal NK/T lymphoma cases are due to diagnostic difficulties and therapeutic problems related to the absence of radiotherapy in our work environment.

Purpose of Study: To report the epidemiological, clinical, therapeutic and evolutionary aspects of rhinoscleroma in ENT departments of university hospitals (Côte d'Ivoire)., Material and Method: Retrospective study of rhinoscleroma conducted in the ENT and head and neck surgery departments in Côte d'Ivoire from January 1980 to December 2008 including the cases of confirmed rhinoscleroma and the treated cases., Results: Fourteen cases of rhinoscleroma were found in 28 years. The early manifestations were not specific enough so the patients were seen with clinical status with obvious disorders or physical discomfort. Treatment was medical and surgical. Medical therapy was based on streptomycin, thiopenicol or ciprofloxacin administration. Surgery consisted in removing the fibrous adhesions to correct the functional and aesthetic disorders., Conclusion: Rhinoscleroma has become a more and more rare disease because of the sensitivity to the new molecules. Diagnosis can be difficult and delayed because of its clinical polymorphism., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Objective: To present our experience of the extraction of the esophageal foreign bodies by cervicotomy route., Patients and Method: Descriptive retrospective study from 2006 to 2010 realized in the ENT Departments of Yopougon and Treichville's Teaching Hospital., Results: 9 (3.3%) of 270 patients underwent surgery to remove esophageal foreign bodies. The average age of the patients was of 14.6 years (extremes: 8 months and 49 years). The foreign bodies were fish bone, hook of clothes peg, medallion, denture and weld. Cervicotomy was performed at once in 4 cases and after failure of esophagoscopy in 5 cases. There were 2 complications (pharyngostoma and suppuration of the operating site)., Conclusion: The cervicotomy must be quickly performed in case of perforation with or without neck abscess, sharp or voluminous bodies.

Ectopic thyroid is the presence of thyroid tissue outside its normal cervical seat. It results from abnormal embryological development. We report the case of an ectopic lingual thyroid found during maneuvers of intubation in a patient of 56 years old. The examination found a rhonchopathy with sleep apnea syndrome and sleep in a sitting position. Endoscopy showed a posterior lingual tumour. The cervical echography showed an absent thyroid in the normal place. Scintigraphy, computed tomography and magnetic resonance imaging confirmed the diagnosis of ectopic lingual thyroid position. The treatment consisted of surgical excision by cervical route after a safety tracheotomy.