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Dołączył: 21 Lut 2011
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 Wysłany: Pią 8:25, 22 Kwi 2011 Temat postu: mbt chaussures paris dpo mma gkqb gwd |
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600MW power plant after the stone part of the protection setting unit
Abstract: After the stone for power plant project (6 * 600MW), mathematical analysis and physical modeling using a combination of methods, 600MW transformer protection using discriminant-side configuration of current amplitude reactive power theory machine loss protection, the use of unit and system power angle discrimination principle of step protection,[link widoczny dla zalogowanych], the use of discriminant third harmonic generator neutral side 100% of secondary value of the principle of stator ground protection are analyzed in detail in order in the configuration and tuning values to meet the large unit for the protection selectivity, sensitivity and reliability requirements, the on-site proof of actual operation, the tuning scheme is feasible. Keywords: transformer unit protection setting calculation configuration stone after the six 600MW power plant design and installation of supercritical coal-fired generating units, as Fujian Province is the largest thermal power plant, relay protection device set to introduce a random group of Japan's Toshiba and Mitsubishi equipment (some purchased ABB, GE Equipment). Now rare in the factory configuration of the domestic protection device and setting the program in principle on a more detailed discussion, criticism for peer correction. 40G1, 40G2 [Model RAGPK]: generator loss of field protection (two sets). Action in the full stop. the smaller capacity of Fujian power grid, active and reactive power reserves are small, then Stone's stand-alone power plant capacity and large, if the unit without loss of field isolated from the system will make system voltage collapse, if the clearing time is too long, not only the generator will vary AB: excitation current limit; BC: the stator current limit; CD: the leakage caused by magnetic heating limit of stator end EF: AVR function in the absence of generators in case of static stability boundary; Xe: infinite bus system equivalent impedance Figure I: Typical capacity curve generator further damage to the generator is running, but will also cause the system generator adjacent to step, cause great harm to the system. China's traditional low-excitation loss protection is a measure of park-side impedance, the operating criteria are asynchronous boundary resistance, static stability of the boundary resistance, static stability limit of excitation voltage and other operating criteria. The factory with the loss of excitation protection criterion for distinguishing reactive power absorbed by unit size and supported by the system voltage criterion. A typical turbine capacity curve as shown in Figure: Stone Power Plant after the loss of field protection unit generator terminal by monitoring the direction of reactive power-based criterion to reactive current and power generation Low-voltage-side as an additional criterion, constitute export conditions, the actual reactive current static stability at the boundary by generating reactive power absorption setting. Generator occurs in the following cases loss of field: ① field winding fails open or short circuit. ② excitation Switchgear. ③ AVR system failure resulting in the excitation current to zero. plant configuration after the two sets of stone produced by the ABB RAGPK type loss protection, installed in the generator terminal, which consists of RXPDK21H and RXEDK2H composed of two relays. RXPDK21H paragraph two movements, a section of the non-directional overcurrent protection (I>>), the current exit; the other direction for some time delay for the over-current protection, the movement equation of ICOS (Φ-α) ≥ Iα (α characteristic angle at -120 degrees to 120 degrees setting, Φ to access the angle between the voltage and current in the secondary voltage is lower than 5 volts, using the angle between current and voltage of memory,[link widoczny dla zalogowanych], the project received A phase current and voltage into the relay.) The relay operation is shown in Fig: RXPDK21H relay operating characteristics of current selection to the following issues into account: ① and low generator Reed and generator capacity curve fit ② static stability boundary curve fit ③ full account of the magnetic generator in case of loss of absorption of reactive current amplitude. For ease of calculation, the establishment of the generator and the system equivalent model as shown in Fig: Xd direct axis reactance of the generator, Xt is the transformer impedance, Xs is system equivalent impedance, Us for the system voltage (assumed to be constant), Uf for the generator terminal voltage (23KV),[link widoczny dla zalogowanych], Ed is the potential direct axis generator, turbine generator to the large system for the transmission,[link widoczny dla zalogowanych], the following formula holds: Ps = Ed * Us * Sinδ / XdΣ (1) Qs = Ed * Us * Cosδ/XdΣ-Us2 / XdΣ (2) where XdΣ = Xd + Xt + Xs, δ for the generator system of direct axis between electric potential and electric potential angle. generator static stability boundary corresponds to δ = 900, the absorption of reactive power Qs =- Us2 / XdΣ constant in the system voltage to a constant value, ie Qs = -Us2 / XdΣ = constant ≈-Uf * ISinΦ == Uf * Icos 〔Φ-(-90)〕 (3) Φ to-side angle between current and voltage (assuming no consider the system and transformer reactive power loss) from the formula (2) shows that the critical step in the generator that is δ = 1800,[link widoczny dla zalogowanych], the generator reactive power absorption of the biggest, according to the formula (3) This point corresponds to Φ = 900, then we can see static stability boundary corresponds to the generator δ = 900 corresponds to the point when the Φ ≈ 750, a single machine case, calculated by the system is stable at this time generator terminal voltage is about 80% rated voltage. according to the formula (3) the establishment of the following equation: Us2 / XdΣ ≈ Uf * ISinΦ obtained in static stability boundary of the generator, the generator absorbs reactive current I = Us2 / (Xd Σ * Uf * SinΦ). take standard per unit: Us = 1.0, Uf = 0.8, XdΣ = Xd + Xt + Xs, where Xd = 2.0 (based on manufacturer data generator), Xt = 0.132 (220KV Grade II under the corresponding time is 9.875 Euro), Xs = 0.169 (220KV level corresponding to the second value is 12.7065 under the EU), the generator absorbs reactive current, in per unit value I *= 1 / (XdΣ * Uf * SinΦ) = 1 / 〔(2 +0.132 +0.169) * 0.8 * Sin750〕 = 0.562. 220KV level in the standards under the generator rated current is I = 706000 / √ 3 * 23000 = 17722 Security, the corresponding secondary standard value I = 17722 / (23000 / 5) = 3.85 Safety . the above calculation, in the static stability boundary in the generator, the generator absorbs reactive current I = 3.85 * 0.562 = 2.165 an, taking characteristics of angle α =- 90 degrees. After taking into account a certain margin, the safety and protection take Iα = 1.89, characteristic angle α =- 900. RXEDK2H low-voltage relay, according to a machine in the generator in case of static stability boundary, the terminal voltage of about 80% of the nominal voltage setting. Is calculated by the end of 1999 the province grid connection mode, in the post-rock power plant under a generator loss of field occurs when the terminal voltage dropped to 80% of the rated voltage, the unit is about 280MVAR absorb reactive power, the delay 0.4 seconds trip. 64G2 [Model RAGEK]: 100% generator stator ground protection. Action in the letter.
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