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The DC power systems of power stations and substations provide the power supply for the key consumers of the auxiliaries, such as are the protection and automation systems that provide faults localization in primary circuits of the electrical installation. Nowadays the protection devices replacement process keeps going. Traditional electromechanical relays are replaced by the modern multifunctional...
The penetration of distributed generation (DG) in distribution power system would affect the traditional fault current level and characteristics. Consequently, the traditional protection arrangements developed in distribution utilities are difficult in coordination. Also, the operation and planning of distribution scheme would be affected. Moreover, the higher demands of power supply make the system...
The paper analyzes the critical technology of condition based maintenance in relay protection, and especially pays more attention to the on-line state maintenance of secondary circuits, including AC analog circuit, switch input circuit and breaker operating circuit. Firstly, the paper uses a comparative method to effectively monitor the AC analog circuit. No matter how relay protection devices are...
The protection of motors used in industrial and commercial power systems is covered. It is likely to be of greatest value to the power-oriented engineer with limited experience in the area of protection and control. It can also be an aid to all engineers responsible for the electrical design of industrial and commercial power systems.
Remote backup protection is installed at the ends of the power line of 35–220 kV and provides detection of short-circuit on the low-voltage side of branch transformers. To support remote protection on 110 kV lines and above with two or multi-way power feed, it is mandatory to implement a three-stage remote protection from interphase short-circuit (phase-to-phase fault). To implement line protection...
The arc column mathematical model taking into account the thermodynamic processes in the damaged equipment is described in the article. The functioning of the model is based on the use of the first law of thermodynamics and the 2nd Kirchhoff's rule. Nonlinear dependencies of the electrical and thermodynamic parameters on temperature and pressure of the arc column plasma play an important role in the...
The research results of the supercapacitors influence on the voltage dip magnitude and duration in DC auxiliary power systems of substations were presented. The several variants of the supercapacitors' placement in DC network were discussed. The estimation of the fulfillment of the electromagnetic compatibility requirements with the consideration of voltage dips in DC network of substations during...
With the development of smart distribution network, the distribution system is introduced with a large number of distributed generations (DGs). It becomes an active network that both the load and fault currents flow two-way, which leads to serious impacts on the protection's selectivity and sensitivity. In this paper, by analyzing current characteristics of a typical distribution network with DGs,...
The intelligent substation uses the communication network instead of conventional secondary circuit, therefore virtual digital signal in the network replaces the physical electrical signal. Thus there is not a one-to-one correspondence between function information signal and the communication network wiring. In intelligent substation, IED is used as common operational platform, and the functional...
Inverter based electric power source constructed of semi-conductor switches is the most important part of DG, and its output characteristics is quite different from that of traditional generator power source during outward short circuit. Therefore, the operation and control of distribution grid will become very difficult if the proportion of inverter source is higher enough. A series of factors which...
As a large number of distributed generations (DG) are connected to the distribution network, the fault current of the distribution network has been changed, and the reliable operation of relay protection in the distribution network has been influenced. In the background whether the negative-sequence current protection can be used in the distribution network containing inverter interfaced DG (IIDG),...
As a large number of distributed generations (DG) are connected to the distribution network, the fault current of the distribution network has been changed, and the reliable operation of relay protection in the distribution network has been influenced. In the background whether the negative-sequence current protection can be used in the distribution network containing inverter interfaced DG (HDG),...
Compared with traditional AC distribution network, DC distribution network, which stands for future distribution network is suitable for distribution generation (DG) to multiple access. DG access changes the structure of low-voltage DC (LVDC) distribution network, affecting the reliability of relay protection. To eliminate the influence, a protection strategy which is based on Hall DC transformer...
Fault characteristics of inverter interfaced distributed generator (IIGD) are determined by its grid-side converter. To deduce the fault current of IIDG is to analyze the current response under the action of grid voltage sags. To enhance the low voltage ride through (LVRT) ability of IIDG when asymmetric fault occurs, the dual current control strategy is widely used. In this paper, the positive and...
In this paper, by installing a filter link in the converter station of a multi terminal direct current (MTDC) system and analyzing its impedance characteristics output, it illustrates that the current measured by the shunt on the HVDC line would be different when fault occurs on the line or not. The filter is made of a smoothing reactor and HVDC filters. According to the current difference, new protection...
Modern electric power systems (EPSs) is a complex, dynamic, non-linear and stiff system. Adequate simulation of processes in EPSs is a non-trivial task. During its solution, in most cases, relay protection (RP) devices are modeled as the simple blocks which are compering input signal with a setting and sending a signal to the commutation equipment. The character and duration of the transients in real...
Modelling is an integral part of end-to-end computer-aided design. However, modelling real-time systems remains fragile and long-term. A method is proposed for the sustainable co-simulation of control objects and devices for relay protection and automation at rapid time of a single calculation. The relevance of objectives is the continual improvement of the hardware components, technological equipment...
This paper takes under considerations to set forth characteristics relating to performance, limited electrical and mechanical interchangeability, and to assist in the proper standard elaboration for Transformers Applied in Distributed Photovoltaic (DPV) Grid, and its relation with existing Standards. It was elaborated by the Task Force for DPV-Grid Transformers of the Power Transformers Subcommittee,...
This paper deals with short-circuit calculation, as one of the basic Distribution Management System (DMS) applications. It is common practice in short-circuit calculations to neglect loads, line and transformer shunt parameters as well as influence of the pre-fault state. This paper shows that some of these approximations could lead to incorrect results when calculating currents at relay locations...
In this paper a real-time short-circuit calculation method for large-scale distribution systems with a high penetration of distributed generators is proposed. Recent years have witnessed increasing penetration of distributed generators. Thus, distribution systems have become active, where the fault current flow is no more straightforward. Additionally, modern distributed generator's models differ...
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